G C Leong - Geography Clean.pdf

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Acknowledgements

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Contents

Metric Conversion T
PART I PHYSICAL GEOGRAPHY

1. The Earth and the Uni
Exploring th.
he shape of the Kar lence of th
Spherity 2: The Earths Movements 4; Di
Night, 4; The Earth Revolution, 5; Dawn

6 Math Location of Place
the Globe, 7; Latitude, 7; Longitude, 8; Longitude
and Time, $; Standard Time and Time Zones 9:
The International Date Line, 10; Questo
Exercises, 10; Selected Cambridge Questions, 11
2. The Earth's Crust
‘The Structure of the Earth, 12; The Classification
of Rod Tgneous Rocks, 12_ Sedimentary
Rocks, 13 Metamorphic Rocks, 13: The Influence
fof Rock Types on Landscape, 14; Earth Move
ments and the Major Landforms, 14: Types of
Mountains, 14; Types of Plateaux, 17; Types of
Plain, 18
3. Volcanism and Earthquakes 20
Landforms Associated. with Vulcanie Act
20; Landforms of Igneous Intrusions, 20; The Ori
gin of Voleanoes, 21; ‘Types of Volcanoes
Extrusive Landforms, 22: Some Voleanic Erup-
tions, 23; The Distribution of Volcanoes in the
World, 24; Geysers and Hot Springs, 25; Ear
thquakes, 26; Some Major Earthquakes, 26; The
Distribution of Earthquakes, 26; Questions and
Exercises, 26.
4, Weathering, Mass Movement and Groundwater

28
‘Weathering, 28: Mass Movement, 31; Groundva-
er, 33; The Water-Table, 34; Springs and Wels,
; Questions and Exercises, 37.

(one and Chalk Landforms
stone and Chalk, 62; Characteristic
y Karst Region, 6
ns of the World, 64; I
Regions, 64; Question and Exercises, 65.
akes
ral, 66; The Formation and Orig
à Man, 69; Questions and Exercis

Tides and Currents, 72: The
72; Coastal Fea
tutes of Erosion, 73: sures of Deposi-
tion, 75; Types of Co Coastlines of
Emergence, 77; Questions and Exercises, 78.
11. Islands and Coral Reefs 7
sal, 79: Coral Reefs, 80; Types of Coral
Reefs 81: The Probable Origin of Coral Reels, 82
Questions and Exercises 83.
12. The Oceans 4
ssploring the Oceans, 84: The Relief of the
‘Ocean, 85; The Deposits of the Osean Floor, 86;
Salinity of the Ocean, 86; The Temperature of
‘Ocean Water, 86; The Movements of Ocean Cur-

Indian Ocean Circulation, 90; Questions and
Exercises, 90; Selected Cambridge Questions, 91.
En

ene Aci 12:
ga Wesen. 113; Moró Cae pes

“and Exercises, 115; Selected Cam

Wet Equatorial Climate 116

116; Climat, 116; Vestation, 18,
the Development of Equatorial
ons and Exerc 120.

122: Seasons of the Tropical Mon-
The Rereaing Monsoon, 124

tion, 144; Economic Development of the Mediter.
Fanean Regions, 145; Questions and Exercises,
17
20, The Temperate Continental (Steppe) Climate
148

Distribution, 148; Climate, 148; Natural Vegeta.
tion, 150; Economic Development, 151; Questions
and Exerise 153.
21, The Warm Temperate Eastern Margin (China
Type) Climate ES
Distribution, 155; Climate, 155; Natural Vegeta:
tion, 138; Economie Development, 158; Question
and Exercises, 161
22, The Cool Temperate Western Margin (British
Type) Climate 163
Distribution, 163; Climate, 163; Natural Veget
tion, 165; Economic Development, 165; Questions
and Exercises. 169.
23, The Cool Temperate Continental (Siberian)
Climate 170
Distribution, 170; Climate, 170; Natural Vegeta
tion, 172) Economie Development, 173; Ques
tions and Exercises, 175.
24, The Cool Temperate Eastern Margin (Lauren
an) Climate 16
Distribution, 176; Climate, 166; Economic
Development, 178; Fishing, 179; Questions and
Exercises, 181.
25. The Arti or Polar Climate 183

‘bution, 183; Climate, 183; Tundra Vegeta-
tion, 184; The Importance and Recent Develop-
‘ment of the Arctic Region, 185, Questions and
u) e cn

Conversion Scales for Temperature and Rainfall

Other Conversion Factors

Part 1: Physical Geography

Chapter 1 The Earth and the Universe

Exploring the Universe

(On a fine bright night when you look up at he sty

ft seems to be studded with stars Lite do

Ae that each of the sari ar bigger an ae

‘arth on which we live. Some of the larger ones
fave been estimated to be many millions of times the
size of the earth. These stats are not scattered
regularly in space; they occur in clusters, better
described as galaxies or nebulas. Each galaxy may
contain as many as 100 milion stars. Its believed
thatthe earth's own galaxy (the Milky Way) alone
contains as many as 100,000 million stars
"The stars appear small to us even through a
telescope because they are so far away. The light
from the nearest star travelling atthe speed of light
(ie. 186,000 miles per second) takes something like
years to reach us. A ray of light from the sun
about eight minutes to reach the earth. Light
takes only a second to reach us from the moon,

The Solar System

The solar system comprises the Sun and its nine
planets (Fig. 1.) which are believed 10 have been
“developed from the condensation of gases and other
lesser bodies. All the planets revolve round the Sun
in eliptial orbits. Like the earth, they shine only
by the reflected light of the sun. The Sun has a
surface temperature of 6,000°C, (10,800°F) and
increases to 20 milion"C_ (36 milion*E) in the
interior. All over its surface are fiery gases that

leap up in whitls of glowing flames like a volcan
in eruption. In size, the Sun is almost unimagina
tis about 300,000 times as big as the earth!

“Amongst the nine planets, Mercury is the smallest
and closest 10 the sun, only 36 million miles away
thus completes its orbit in a much shorter space
of time than does Barth. A year in Mercury is
only 88 days. Venus, twie the distance away from
the sun, isthe next closet planet. It is often con-
sidered as “Earth's twin’ because of their close
proximity in size, mass (weight) and density. But no
Other planet able to Earth which
has life and all the livin ‘we see around us.
Tike many other plane à natural
satelite, the Moon, 238,900 miles away, that revolves
‘tstvard around the Earth once in every 27 days.

The fourth planet from the sun is Mars which
has dark patches on its surface and is believed by
‘most profesional astronomers to be the next planet
after Earth to have the possibilty of some plant
Tif Much attention has been focused on Mars to
explore the possibilities of extending mans influence
fo it Next comes Jupiter, the largest planet in the
solar system. Its surface is made up of many gases
Tike hydrogen, helium, and methane. Tt is dis-
tinguished from other planets by its circular light
“and dark bands, and the twelve satelites that circle
round it. As it is more than 485 million miles from
the Sun, its surface is very cold, probably about
20°F. (130°C),

Fo. 1 The Solar System—the Sun andthe ine Panels

oct is Sarum which has hrs

“ps
nn
ne sen
en
run
a
e
=r ee gig gens
“ols Eig beled
RCE
D eee
D nie
D ur
co ES
e ee
a ie
pee

The Shape of the Earth
Inte olden day sors feared to venture far into

round In Se, it
tis 0 far o
1 complete is ori

There are min
spheric Th

the earth i spherical, N

or by land or sea has ever encountered an aby
fudge, over which he would fall. Modern air rou,
And occan navigation are based on the assumptiga
thatthe earth is round (Fig. 2) |

horizon. The distant horizon

fo e io ipa or fom a
de everywhere circular in shape

This calar horizon widens with increasing ltd

Over the curved surface is equal

Fig. 4 (b) A Mat earth, the entire ship is seen at once
aa surface

Fig. 2 (a) Increasing altitude widens the circular hor
zon. Viewed trom Y the horizon wosia te
AB but from a higher viewpoint D wider
horizon (6, DJ would be seen

1. Sunrise and sunsel. The sun rises and sets at
diferent times in different places. As the earth
"lates from west 10 east places in the cast see the
sun cari than those in ıhe west. If the earth were
fat, the whole world would have sun and sunset

But we Know this is not so.

at the same time
Fig. 5 strates this

(D) Visible horizon remains the same regardless

of alitude. i the ‘earth were Mat the j
horizon soon from either Y or X would be 4
the same

gradual. IF the earth were fat, the entire ship would Fig 5 (a) Sun risos and sun sets st diferent times
be seen or obscured all at once. This is apparent for diferent places

from Fig. 4,

tog

ne con

(0) The whole world will have sun rise or sun

ip is soon before the hull
sotatthe same time

Fo. 4 (6) The most of
‘on curved horizon

The lanar cele. The shadow

the moon during the lun

»

On a sphere can est so

6. Phantary bodies are spherical. All observations
fiom telescopes reveal that the planetary bodies,

stars have circular
oui om whichever ange you see them. They
ane sy spheres Earth, by analogy, cannot be

the Sun, Moon, satelites a

he onb exception.

7. Driving pokes on kel ground on a curved earth.
Engineers when driving poles of equal length at

regalar intemals on the ground have found tha th

do aot gie a perlct horizontal level. The centre
pole normally projets slighty above the poles at
iter end baue of the curvature of he earth, as
israel in Fig. 6. Surveyors and field engineers
therfore have to make certain corrections for this

inestable curiatur Le. S inches to the mile

Fo. 0) Te cone pol projects well above the
Pie arr cre ne wit’

ast by the
eclipse is ahays
are of a ende

The Earth's Movement

Man is lays conscious of the apparent movement
of the sun’ and little realizes that the earth on which
he stands is constant in motion, When the sun
¿isapcars he sys thatthe sun st and when i
mete, he says that the sun rises He ds not the
Jest aware tht the sun, infact, dos not rs ot
itis WeWho rie and we who set! The earth moves
is Space into dint ways i rates on ls own
a from West toast once never) 24 hours causing
day and night: aso revolves round the sun in an

ori ona
rs oe in ey 368 day ang ds

Day and Night
When the earth rotates on its own

tes on axis, only one
‚Portion of the earths surface comes into the rays of

‘The earth vowed
rom the moon.

the sun and experiences daylight. The other portion
which i away from the sun rays will be in darkness.
As the earth rotates from west 10 east, evry part of
the earths surface will be brought under the sun
at some time or other, A part of the earth’ surface
that emerges from darkness ino the sun's rays
experiences sunrise. Later, when it is gradually
obscured from the sun's beams it experiences sunset.
The sun is in fat, stationary and tis the earth which
rotates. The illusion is exactly the same as when we
travel in a fastemoving train, The trees and houses
around us appear to move and we feel that the
‘rain is stationary. Fig. 7 explains the earth’
‘lation and the causes of day and night

The Earth's Revolution
When the earth resolves round the sun, it spins on
‘nelliptical orbit ata speed of 18.5 miles per second

Fig. 7 (a) Kuole Lumpur emerges from darkness
Inte daylight st sun rise when the ort
rotate tothe sua aye
Lumpur er my = y

(6) Kuala Lumpur passes from daylight into
arkness al sunset when the earh rotates

(@) Kuala Lumpur is directy away from the
Sun ami night

or 66600 mph. One complete revchuion takes
654 days or a year, As itis not possible to show
a quarter of a day in the calendar, a normal year is
taken to be 265 days and an extra day is added
every four years asa Leap Ye

1. Varying Lengths of Day and Night
‘The axis of the earth is nlined to the plane of the

celipic (he plane in which the earth orbits round

the sun) at an angle of 66", giving rise to diferent

seasons and varying lengths of day and night (Fig 8).

Ifthe axis were perpendicular to this plane, al parts

‘of the globe would have equal days and nights at

all times of the year, but we know this is not so.

In the northern hemisphere in winter (December)
as we go northwards the hours of darkness steadily

increase. At the Arctic Circle (66i°N), the sun
never ‘rises’ and thee is darkness for the whole day
in mid-winter on 22 December. Beyond the Arctic
Circle the number of days with complete darkness
increases, until we reach the North Pole (90°N)
‘when half the year will have darkness In the summer
(une) conditions are exactly reversed. Daylight
increases as we go polewards At the Aretic Circle
the sun never ‘Sets! at mid-summer (21 June) and
there is a complete 24-hour period of continuous
daylight. In summer the region north of the Arctic
“Ciel is popularly referred to as ‘Land of the Mid-
night Sun. At the North Pole, there will be six
months of continuous daylight. Fig. &a) illustrates
the revolution of the earth and its inclination to the
plane of the ecliptic which cause the variation in
the length of day and night at different times of
the year

Fg 8 a) The revolution of th ert and its facts on
sone andthe vara ons of lngths of day
nai

zu on mais ee
se two days all parts othe
eo and mat ANE ea
no the sun appears 10 move north and i yg
eau rica at Ihe Tropic of Cancer (23°)
Steen one
the northem hemisphere will
eas
Ae ape sun wil be overhead at he 7
Deeb, ie the ier sae
hen the southem hemisphere will hve its Loge
Uy and shortest night, The Tropics thus mark ty
figs ofthe orerbead sun, for beyond these, the ug
is never at any time of the year. Sut
sons are marked by distinct seasonal changes
Spring, summer, autumn and winter. Beyond the
Arse Circe (SSPN) and the Antarctic. Cig
(688) where darkness lasts for 6 months ang
dayigh is continuous forthe remaining hal of the
eat it i always col; for even during the sho
Summer the sun is never high in the sky. Within te
tropics, as he miéday sun Varies very litle from i
vertical position at noon daly, the four seasons ae
almost inisiguisable. Days and nights are ab
mos equal al he year round Fig. 8().
3. Seasonal Changes and hir cts on Temperature
Summer is usually associated with much heat and
brightness and winter with cold and darkness. Wiy
ould this be so? In summer, the sun is higher in
the sky than in winter, When the sun is overhead
is rays fall almost vertically on the earth, con
String is heat on a small area; temperatur
therefore des and summers are always warm.
In winter the oblique raÿ of the sun, come through
the atmosphere less directly and have much of thei
eat absorbed by atmospheric impurities and water
Nee Hs fall faintly and spread over
mt an ‘is thus little heat, and tem
ion, days are longer than nights in summer
nd more heat recived over the longer daft
rai. Nigh are shorter and less eat i ot.
835 gin in toa Heat recived and te
oo Summer. Shorter days and longer
account fr he reverse effect.

days ar te
because on th

its longest day

nights.

the sun wit tel tow the horizon, Since the
the es and exe in a vera pa atthe equator
fa eo drag whit raid Ui is eco
the tore But in tempera Ittude the sun es
Evian oblique path andthe period of reacted
as longer Ce much longer il tthe poles
Mat he winter darkness i relly only wight
Bator the ine (Fi: 9)

Fig. 9 Dawn and Twilight
Aa) atthe equator
(6) in tomporate latitude

m de

‘Ate equator the sun rises and sets almost vertical
0 the timo it takes to passthrough the twilight zone”
(A, 8 willbe shorter than for temperate latitudes were
the sun rises and sets obliquely Here the time taken

o passthrough the tight zone (CD) s longer

Mathematical Location of Places

on the Globe

‘The earth's surface is so vast that unless a mathe-
‘matical method can be used, it is impossible to
locate any place on it, For this reason, imaginary

tines have been drawn on the globe. One set running.
fast and west, parallel 10 the equator, are calle lines

SF laiude The other set runs north and south
passing through the poles and are called lines of
Tongitude (Fig. 10). The intersection of latitude

a. N

Fi 10 (a) Paral otto

1 Martins oflongiude
and longitu pin-poins any place on the eats
Surface (Fig. MO), For example Debi is 28%57
Nan TRIO Es London & 51930 N. and
SW. and Sydney is 3958 S, and 151°12 E We
shal examine more closely how tue and longitud
Are determined andthe oe they playin mathematical
oran

Latitude

Latitude is the angular distance of a point on the
arts surface, measured in degrees from the centre
ofthe earth as shown in Fig. 10e) It is parallel to a
line, the equator, which lies midway. between the
poles These lines are therefore called parallels of
latitude, and on a globe are actually circles, becoming
smaller polewards. The equator represents 0° and
the North and South Poles are IN. and 90°S.
Between these points lines of latitude are drawn at
intervals of 1°. For precise location on a map,
each degree is sub-divided into 60 minutes and each
minute into 60 seconds The most important lines
fof latitude are the equator, the Tropic of Cancer
ND), the Tropic of Capricorn (234%), the Arctic
ile (SN) and the Antarctic Circle (661°S).
As the earth is slightly Mattened at the poles, the
linear distance of a degree of latitude at the pole is
‘lite longer than that at the equator. For example
fat the equator (0*) it is 68.704 miles, at 45° it is
69.054 miles and at the poles it is 69.407 miles
‘The average is taken as 69 miles This is a useful
figure and can be used for caleulating distances to
any place. Bombay is 18:55*N; it is therefore 18:55 x
69 o 1280 miles from the equator, With the aid of
‘your atlas find the approximate distance of the follow

7

ing places from the equator: Singapore, Caleuts,

Paris New York Buenos Aires and Auckland

Fg. 11 (0) The étude of SBN. is the anguler
stance 0 à point on the sois surace north of the
ene of haere

wy

lp) The ong 135% isthe angular
stance west ofthe Prime Meridien Y

through the Royal Astronomical Observatory y

* Gremwich, near London. This is the Prime Merian

ma al oe melas ras cua
nn opto 189. Sms the cath span
acens cased 25000 ral
Res ec of te 360 dates of longi
fst deat cc 6 mike Av De pal
Hii bone toner ro ze Be mene
Sie wich comer tthe poles, is
ir race The deg of longe tenis
ec I eg, Whee longest -
te mas 62172 mies At 26 iis gna
D a 4 49 mi u 75 1 mie anh
the pola 0 mie The so mach din
helen ges of lng ote the tp
ta day au zei oe celos eae
In he a of tte But thy ne one ve
inporant sion, ley deine al Un Y
rason 1 GMT. br Crema Hon Tono via
romaines re oa: Word Time

Longitude and Time

Local Tine. Sine the earth makes one comple
revolution of 360° in one day of 26 hours, it pass
through 15° in one how or 1* in 4 minutes The
carth rotates rom west fo eas, so every 15° we go
exstvards local time is advanced by 1 hour Con
Yeneby i we go westwards local time is retardo
by 1 hour. We may thus conclude that paces eat
of Greenwich see the sun carie and gain tine,
whereas places west of Greenwich se th sun lite
and lose time. If we know GM.T, to find local
tng mer me ad or suit the ie
in the number of hours from the given longitude
as lated below. À sinple memory aid for ts
will be East Gai-Adi (EGA) and West Late
‘Subtract (WLS). You could coin your own rhymes
for the abbreviations. Hence when it is noon, in
London (Longitude 0°SW), the local time for
Madras (80°E.) will be 5 hours 20 ites ahead
ef London or 520 pm. But the local tine
for New York (74°W) will be 4 hours 56 minutes
‘behind London or 7.04 a.m. ‘We can put it in another
3; when Londoners are having lunch, Indians vil
Do non will have breakfast.
i ds dificult o believe, but it is tru
{Pelton o he eat round the sun means ia
gay Point in time different places will experience
a different time of day. ie

J ‘are many ways of determining the longitude

ete way is to compare the
local time with GMT. by listening to BBC radio |
|

es son 1 sf
m Ge]

5 ‘when ts noon in London.
AIS 520 pam. ln Madras

1 (20°) and 7.04 um. in New

i York ra Wi

For example the captain of a ship in the midst of
the ocean wants to find out in which longitude his
ship les If GMT: is 800 am. and itis noon in
the local region, it means that he is four hours
ahead of Greenwich, and must be east of Greenwich
His longitude is 4 x 15° or 60°E,

Standard Time and Time Zones
Teach town were to keep the time ofits own meridian,
there would be much difference in local time between
‘one town and the other. 10 am. in Georgetown,
Penang would be 10.10 in Kota Bharu (a diffrence of
24° in longitude). In larger countries such as Canada,
USA, China, India and USSR. the confusion

sing from the differences alone would drive the
people mad. Travellers going from one end of the
country o the other would have to keep changing
their watches if they wanted to keep their appoint
ments This is impracticable and very inconvenient

‘To avoid all these diiculties, a system of standard
time is observed by all countries. Most countries

opt their standard time from the central meridian
oftheir countries, The Indian Government has accep-
ted the meridian of $25" eat for the standard time
Which is Shrs 30 mins ahead of Greenwich Mean Time.
‘The whole world has in fact been divided into 24
Standard Time Zones, each of which differs from
the next by 15° in longitude or one hour in time,
Most countries adhere to this division but due 10.
the peculiar shapes and locations of some countries,
‘easonable deviations from the Standard Time Zones
Sannot be avoided (Fig. 13).

Larger countries like USA, Canada and

>

USSR. which have a great east-west stretch have
to adopt several time zones for practical purposes.

USSR, the largest county, which extends through

almost 165° of longitude is divided into eleven time

zones. When it is 10.00 pum. on a Monday night

in Leningrad, it will be almost 7.00 am. the following
‘Tuesday morning in Viadivostock. Travellers along.
the Trans-Siberian Railway have to adjust their
watches almost a dozen times before they reach
their destination. Both Canada and USA. have
five time zones—the Atlantic, Eastern, Central,
Mountain and Pacific Time Zones. The diffrence
between the local time of the Atlantic and Pacific
coasts is nearly five hours (Fig. 13).

Fig, 13 The five time zones of North America

Strait, Fi, Tonga and other islands to Pre Q, Work out the following (a) Sydney long. IE) q

oes oe = = ee be | i, What is the approximate distance in a (0) Chicago, long. 8730),
groups that are cut through by the mesias. Sa straight ine between Caio at 300 (©) Bombay (long. 7PE)
ee ray tn OER Aste os Non Zen! ago Te Tong. 31°S amd Durban dat. 29°57 ‘The captain of a ship observed that it
ua obs fob te Amer de re TI long. ST EN Vas loc moon. He turned on th radio
D ns Teatral Date Line is shown Fi i, When its 200 pm. in Greenwich, what and listened to the 7.00 am. BBC
isthe local ime of news, What was his longitude? |

QUESTIONS AND EXERCISES
eden ent ost Wahi lomas ten LECTED QUESTIONS FROM CAMBRIDGE OVERSEAS SCHOOL CERTIFICATE PAPERS
aie si in as a rove that he cath rt Ge =) |) pun he mening te ers Equinos and Sala
AN (sso ag ev ed elo moon ec)
“it is midnight, Friday on the >. Explain with the aid of fairly accurate dia- ci SEHR
a ae an ce cy a (a) Describe any three experiments or observations which support the belief that the earth is roughly a

grams, how the tilt of the earth’: axis on its AR
Fi D RES (b) Explain why mean temperatures for London are lowest in winter,
= = (9. Explain why the local clock time in the Samoa Islands (171°W) was noon on Ist November when ia
IC), ans ne gt of dy and the Fi Islands (178°E), it was 1,00 am. on 2nd November (1966) Ñ
sigh 3. Explain the following
(©. thealtitde of he midday sun to hang D toate ioe ay eae
at diferent times ofthe year. (8) When itis noon at Cairo (AU te local time in New York SW) is $00 am.
(9) On 2lst March at noon it was observed thatthe shadow cast by a val 8 ins: high poa
BR ale ens toca met Ward and vas i lo. The observer was able fo alulate is atte o be about N!
the following: 4. Select wol (a), 0). () and draw diagrams to strate your answers:
(6) perihelion and apheion {@) i Calcule the longitude of he positon of a ship whose navigation fier observes ht G
(0) para of latitude and meridians of Mean Times 14.16hours when the focal mei noon
Tongitude E i, Explain the geographical fact which enable you to make the calculation.
© the ears rotation and the earths re (6) Explain uly why 25th December in New Zealand may be one ofthe hotest ays of the year
olution {©) Why must a trace, when crossing North America from New York o the west

(@) solstice and equinos. Watch at special places. (1964)
(©) Standard Time and Greenwich Mean | 5. With the aid of annotate diagrams explain the following: ‘
Time (2) The apparent daily movement of the sun and is changes during the year as observed MM

i. atthe Equator. 38

4. Explain any sree of the following tems À. ata place SUN.
‘connected with the earth and its planetary (b) The relationship between latitude and the angle of elevation of the noonday sun.
relations: | 6. Explain the effect of
i. galaxy ©), Latitude on temperature, og
fi, Pime Meridian (®) Latitude onthe length of day and night
iii, elliptical orbit. (©) Either: Altitude on temperature,
iv International Date Line Or Longitude on tine (1961)

Give an explanatory account of the

w exacly how the earth was
lin years ago, but from the

Fig 16 À section showing how ho continental)
fats onthe denser SIMA Ee

her is estimated to be as high as 3,50, and the
ore is subject 10 extremely high pressure. Unde
such conditions, the core could be expected to be na
Higuid stat. But recent studies through earihgusle
Yves have suggested thatthe innermost part othe
or is probably a erysaline or solid mass

Pans of the art's crust are immersed by ocean
and seas These form the hyürosphere Extending
skyward for over fe miles the ert is emeloped
y a mass of gases which make up the aimosp

The Classification of Rocks
‘The earth's crust is made up of various types of rocks,
diering from one another in texture, sıru
colour, permeability. mode of occurrence and degree
Of resistance to denudation. A knowledge of these
rocks is of paramount importance to geologists
io sd e compostion aná ik Boy of
‘geographer, 100, needs a basic
Knowledge of the most common fos and the
With landforms. Rocks also form the

= for soil, and determine to some extent the type

of natural vegetation and land use, so we must ave
with the rocks around us

y speaking, all rocks may be class

major groups—jgncous, sedimentary and

‘coring to thie orga and ap-

in

These cont reatel el
some depth inthe cars crust. They have cooled
and solid slowly so that are, easiy-resopnized

enysals ha
rocks

ble to form. These intrusive

such as granite, diorite and. gabbro,
the surface by the processes of denuda
and erosion.

2. Volcanie rocks. These are mi
out of voleanoes as lavas. They

en rocks poured
soldi rapid
re smal

Basalt is a common volcanic or rock
and forms lava flows, lava sheets and lava plateaux,
8. those of Antrim in Northern Irland, the Deccan
Plateau in India and the Columbia-Snake Plateau in

SA. Some kinds of basalt solidify in a very
peculiar manner 10 form long polygonal columns.
‘A well-known example is the columnar basalt of the
Giants Causeway in Antrim. Some of the molten
Jasa may push its way to the surface through clefts
and passages, solidifying as vertical dykes or hort.

ontal sills Their origin and occurrence will be
discussed in greater deal in Chapter 3.

Most igneous rocks are extremely hard and
resistant. For this reason, they are quarried for
road-making and polished as monuments and grave

‘Sedimentary Rocks

Sedimentary rocks ae formed from Sdiment se.
ulated overlong periods, wualy under vale
‘hey aro distinguished Tom the oer rock ps
in tbe carece ner formation and are
termed. sled ross. The sum muy sary in
thickness fom a ow incest many et The rocks
muy be cose or finegrained, sat or hard. The
malle that form sedimentary rocks may be
brought by steams later winds or even animals
‘They are nonenpsiaine and often contain ie
of animale plans and other mcro-organiams Sede
mentary rots ae th the mow sad in er
formation of al racks. Sedimentary rocks are
laa according to ir ae and diferent kinds
rocks formed during the same period ar grouped
‘cee or a hon ess

ee

1. Mechanically formed sedimentary rock. Ti

xs from the accumula
materials derived from other rocks whi

de mot Bale en) AN
made from sand grains, often quartz fragments
derived from granites Their texture, composition
and colour vary tremendously. Many types of

Sandstones have been quarried for building purposes
or for making grindstones. A coarser type of sand:
Stone is known as grit. When larger pebbles are

firmly cemented 10 form a rock iti called
( when the pebbles are rounded, when
the fragments are angular. The finer sedimentary
materials form clay, widely used for brick-making
und grwvel may occur in

uncemented form.
2. Organically formed sedimentary rocks. These
rocks ae formed from the remains of living organisns
such as corals or shells, whose Resby parts have
been decomposed, leaving behind the hard shells
The most common rocks formed in this way are of
the caleareous type. They include limestones and
chalk

The carbonaceous rocks are also organically
formed but from vegetativo matter—svamps and
forests The pressure of overlying sediments has.
compressed the plant remains into compact masses
‘of carbon which eventually become peat, lignite oF
oa al of which beat great economie value.

‘potash and nitrates may be formed,
Metamorphic Rocks

AU rocks whether igneous or sedimentary may
‘become metamorphic or changed rocks under great
heat and pressure. Their original character and
appearance may be greatly altered by such forces,

5
E

> A be En
En
ee Eso Cor ec
nl lo Beis sale nto Sit and
re Fe

a

$

Mi hillnear Kuala Lumpur. Compare
th helimestonafeatures shown in Chapter?

peaks rise 10 over 2,000 feet,

of

smooth slopes and rounded

present landforms are very varied and diene, ot
these agents only modify the pattem of meus
pees mieux

Sine the dawn of gcologcal time, no ls thy
have taken place, folding and fracturing the can
crust Some of them occured. in Pro Cambios
fines between” 600-2500 milion peurs que ad
three more récent orogenis are the Cole,

Hereynian and Alpine. The Caledonia about 32
million years ago raised the mountains of Scandinavia
“and Scotland, and is represented in North America

These ancient mountains have been worn down
no longer exhibit the striking forms that they n
‘once have had. In a later period, during the les
€ynian earth movements about 240 milion years ag,
were formed such ranges as the Ural Mountains
the Pennines and Welsh Highlands in Britain, the
Harz Mountains in Germany, the Appalachi
‘America as well as the high plateaux of Siberia
‘China. These mountains have also been reduced in
Size by the various sculpturing forces

We are now living in an era very close to the last
of the major orogenic movements of the earth,
the Alpine, about 30 million years ago. Young fold

main ranges were buckled up and overthrust on a
igantic scale. Being the most recently forme,
these ranges, such as the Alps, Himalayas, Andes
“and Rockies (shown in Fig. 17) are the loftiest and
‘the most imposing. Their peaks are sometin
several miles high. But the time will come when
these lofty ranges will be lowered like those that
‘existed before them, From the eroded materials,
ew rocks wil be formed, later to be uplifted to form
the next generation of mountains,

Types of Mountains

Mountains make up a large proportion of the
‘arth’ surface. Based on their mode of formation,
our main types of mountains can be distinguished.
1. Fold mountains. These mountains are by far the
‘ost widespread and also the most important
‘They are caused by largescalo cist movements
when stresses are set up in the earth's crust, Such
Stresses may be due to the increased load of the
‘overlying rocks, flow movements in the mantle
‘magmatic intrusions into the crust, or the expat

Or contraction of some part of the earth. When
such stresses are initiated, the rocks are subjected
10 compressive forces that produce wrinkling. or

[Arceo anne rots

| e:

Fig, 17 Structural divisions ofthe warth

folding along the lines of weakness As iastrated
in Fig. 1S() and (b) folding ffcetively shortens the
creating from the original leve surface
a series of ‘waves’, The upfolded waves are called
anticlins and the troughs or downfolds are synclines
The formation of up- and downfolds elosely resembles
that of the wrinkles of a table-loth when its pushed
from ether one or both sides of the table.
Tn the great fold mountains of the world such as

earth ers

18 (9) The horizontal stata of the earth's crust
before flag,
(6) Compression shortons the crust forming
fold mountains

the Himalayas, Rockies, Andes and Alps, due
do the complet of the compressional fre, the
folds developed much more compl ems,
‘When the rest of folds pushed 100 fa, an rod

is formed (Fig. 19). If it is pushed stil further,
becomes a recumbent Fold (Fig. 19). Im extreme
cases, fractures may occur in the crust, so that the
upper part of the recumbent fold slides forward
‘over the lower part along a thrust plane, forming an
Dverthnist fold. The overriding. portion of the
thrust fold is termed a nappe (Fig. 19), Since the
rock strata have been clvated to great heights
sometimes measurable in miles, fod mountains may

Fig. 19 Types of folding

be called mountains of elevation. The fold moun-
ae also closely associated with vokanic activity.
‘They contain many ative volcanoes, especialy in the
Circum-Pacife fold mountain system. They also
‘contain rich mineral resources such as tin, copper,
‘gold and petroleum.

15

Fig. 20 Normal, reverse and transcurent faults

2. Block mountains, When the earths crust bends
folding occurs, but when it cracks, faulting takes

place (Fig, 20). Faulting may be caused by tension
‘ compression, frees which lengthen or shorten
the earths crust, causing a section of it to subside

or to

above the surrounding level. Figs. 21(a)

and () plain how faulting cases horse or block

and their counterparts. graben or

in

forces that tend to pull the crust ap
developed, If the block enclosed by the
remains as itis or riss, and the land
subsides, the upstanding block x
fo block mountain. The faulted cd
Steep, with scarp slopes and the summ
level, eg. the Mi

Black Forest of 1

sruck Mountains, the Vos
Rhineland

Fig 21 (a) Block mountain (art formed by tonsion
when faults develop 4 E

a
Bf fred y compres non

scale block

3. Volcanic mountain. These are, infact, volcanoes

fall around the vent in sue
esse layers building up a characteristic volcan
one (Fig. 2). Voleanie mountains are often called

mountains of accumulation. They are common in
the Circum-Pacific belt and include such voleanie
peaks as Mt. Fuji Japan) Mt, Mayon (Philippines),
Mt. Merapi (Sumatra), Mt. Agung (Bali) and Mt
Catopaxi (Ecuador), Further details are given in
Chapter

Fig 22 A volcano or ‘mountain of accumulation’ with
‘successive layers of lava

4. Residual mountains. These are mountains evo
fed by denudation, Where the general level of the
land has been lowered by the agents of denudation
some very resistant arcas may remain and these
form residual mountains, eg, Mt. Manodnock in
USA. Residual mountains may also evolve from
plateaux which have been disected by rivers into
Fills and valle like the ones illustrated in Fig. 23.
Here the ridges and peaks are all very similar in
height. Examples of dissected plateaux, where the

Fig. 23 Residual mountains or mountains of

have eroded the uplands into
are the Highlands of
nd the Deccan Plateau,

Types of Plateaux
Plateaux are elevated uplands with extensive level
and usually descend steeply to the surround

ing lowland. T
tablelands Like all highlands, plateaux are subjected
to erosional processes. As & result, their original
‘haraeteristies may be greatly altered. According 10
their mode of formation and their physical appear:
ance, plateaux may be grouped into the following
‘ype
1. Tectonie plateaux, These are formed by ca
miovements which cause uplift, and are normally of
à considerable size, and fuir uniform altitude
They include continental blocks like the Deccan
Plateau in India. Some of the Lectonie plateaux may
be led ike the Meseta of central Iberia, or faulted
like the Harz of Germany

‘When plateaux are enclosed by fold mountains,
they are known as intermont plateaus. Examples
fare the Tibetan Plateau between the Himalayas and
the Kunlun, and the Bolivian Plateau between two
ranges of the Andes. Intermont plateaux are some
‘of the highest and the most extensive plateaux in the
word.
2 Voleanie plateaux. Molten lava may issue from
the earth’ cust and spread over is surface to form
success sheets of Basltie lava. These soli 10
form a lava plateau. Some of the better known
volcan plateaux are the Antrim Plateau of Northern
Trland and the northwestern part of the Descan
Plateau, The most remarkable plateau built by lava
is the Columbia-Snake Plateau which covers an area
“almost twice as big as Malaysia. Each layer of the
lava flow is over 100 feet thick and the entre depth.
fof successive lava layers is estimated to be almost
mile

xy are sometimes referred 10 as

mn

. Dissected plateaux. Through the continual pro-
ering and erosion by running water, ice

high and extensive plateaux are gradually
their suis made regular. I
“highlands, stream action and sometimes

cut deep, narrow valleys in the plateaux,
described as dissected plateaux. An

rivers and abrasion by winds
the plateau into steepsided tabular masses
sas and utes intersected by deep canyons

4 common feature of arid and semi-arid arcas,

rem USA.

al and iron and the plateau
¡gold and iron.

‘Some of the largest depositional plains are due
deposition by large in u
upper course results in large quantities of alluviug
being brought down 10 the lower co
10 form extensive
They form the most productive ap,
cultural plains of the world, intensively tilled ang
very densely populated. The Nile delta of Egypt i
noted for rice and cotton cultivation, the Gangs
delta for rice and jute growing, while the plain of
1 where the Hwang Ho has spread out à
tle of alluvium, supports a wide range of

Active erosior

tse and depositg

Glaciers and ice-sheet may deposit a widespread

le ol unsorted fivio-lacial sands and grave
D digan pein or may drop Boulder Sy a
mature of various sizes of boulders and clay, 1
form a til pain or drift pain. Outwash plain are
‘sally bare lands eg, some pars of Holland and
northern Germany, but boulder clay may be very
valuable farming land eg. the Mid-West ofthe USA.
and Eas Anglia in England

Tn coastal regions, waves and winds often dive

teach materials mud, sand or shingle landwards
and deposit them onthe coastal paint form marine
Svamps mudflats, tidal and estuarine lowlands: An
Aappresiable portion of the coastal lowlands of
Belgium, the Netherlands and the Gulf Coast of
USA. were formed in this way. UHR may raise
the coastal lowlands slighty and they then form an
emergent coastal plain eg. the coastal margins from
Florida to Texas.

inds may blow acolln deposis—very fine
parties known as loss —from interior deserts or
baren surfaces and deposit tem upon hie alles
or plains forming a Jess plaeay, as in nor west
“China, oF a oes la, asin the Pampas of Argentina.
“The loss helps to level an undulating plan by filing
up grooves and depressions. Many of the los
covered plans in the world are frie agricultural
“regions.

3. Frosional_ pains, Th

plains are carved by
ion. Rain, rivers, ie and wind
he iregularitis of the earths
f milions of years, even high

the agents
hep to
surface, and in terms

mountains can be reduced to low und
Such plains of
ing almost plain

ine plains.

à word me
Rivers, in their course from source to sa, deepen
their valleys and widen their banks. The projecting
spurs are cut back so that the level ground bordering
the river is constantly widened, At
the higher land between
lowered (Fig. 24
Tn glacated regions glaciers and ice-sheets scoured
and levelled the land. forming
Hollows scooped out by the ice are now filed by
takes There are extensive icescoured plains in
northern Europe and northern Canada. Finland is
estimated 10 have 35,000 lakes, occupying 10% of the
total land surface ofthe county
In arid and semi-arid regions, wind
much of the eroded desert materials,
Towering the level of land and forming extensive
plains, eg, the gravelly or stony desert plains called
in Africa. Mechanical weathering in arid and
sembarid areas wears back the mountain slopes 10
leave a gently sloping Fie,
29.

ually

Fg, 25 Pein >
a formation of a podilan in ad or
ici condone the His are worn back
Form a soy sloping la but some soap
remain These are called Insebergs

QUESTIONS AND EXERCISES

1. Either: Attempt a classification of mountains
according to their mode of formation,
Explain why a knowledge of rocks and
he structures is essential in the inter
pretation of landforms

or

With the aid of diagrams, explain the difference
in appearance and formation of any thee of the
following

(folds and faults

{b) dissected plateau and intermont platea

(9) allavial plain and peneplain

(4) Sima and sil

(©) lithosphere and mantle

3. What is a sedimentary rock? In what way is it
different from igneous rocks? Describe the
Various sources from which sedimentary rocks
may be derived. (Quote actual examples of
‘Sedimentary rocks to support your answer)

4. For each of he following:
‘young fold mountain

ari valley

‘loess plain

Draw a simple diagram to show its charac-

teristic rei,

Explain its origin

Name and locate a region where such a

feature may be found.

@

0)
©]

5, Either: Describe and explain the following selec
‘landforms

(a) Antrim Plateau

(0) Rosin Platform,

(©) Scottish Highlands

Explain the meaning of any four of the
following terms connected with the study

‘of landforms and the earth’ crust

basalt, orogeness recumbent fold, fssilierous rocks,
horst, syncine.

Or:

SH

Chapter 3 Vulcanism and Earthquakes

Landforms Associated
with Vulcanic Activities
Vulcano ati fase «profound influence onthe
earths lanos Sol, iid or gasous materials
‘ay find thir way to the surface rom some dey
‘tied resent beneath. Molin magna is mobile
rock that foes is vay into the plans of woes
Of the est to escape quietly or explose 10 the
Surface The resultant landforms depend on the
Strength and ld of themes, th typ of ecke
faults and joints that entras and the manner in
‚sich it escapes 10 the surface Magma lie
hrsg its way up o the surface may cool and
soif within the era as plutonic rocks resulting
landfooms Magmas tht reach the su
‘face and sbi form exis ndiorm Rocks
formed by ciber plutonic or van activity are
called enous rock

Landforms of Igneous Intrusions
ste commonest intrusive landforms are ils
When an intrasion of molten magma is
along the bedding planes of
rocks the resultant intrusion called a
ofthe orig sedimentary strata
ntrusion which will esemble a Jara
ke the Great Win

85 narrow walls of igneous rocks
layers are termed as dyes.

Because of th

the landscape. When exposed
may appear as upstanding walls or shallow trench,
‘depending on whether they ar tant
than the rocks in which they are emplaced. Example
‘of dykes are the Cleveland Dyke of Yorkshire
England and hundreds of others in the Isles of Mull
and Arran in Scotland. A large, very resistant dyke
‘of quartzite forms a long ridge to the north of Kuala
Lumpur.

Igneous intrusions on a larger scale are the various
types of ith’ laccolths,lopoiths, phacolihs and
baiholiths (Fig. 26). The names may sound dieu,
they are in fact, all variations of igneous intrusi
placed differently in the earth's crust, and soldifying
Within the upper layers of the crust, A laccolith is a
large blister or igneous mound with a dome-siaped
upper surface and a level base fed by a pipe-like
conduit fom below. It arches up the overlying
Strata of sedimentary rocks, eg. the laccoliths of the
Henry Mountains in Utah USA,

A Topolth is another variety of igneous intrusion
With @ saucer shape A shallow basin is formed
in the midst of the country rocks. The Bushveld
Topos of Transvaal, South Africa are good
examples.

A phacolith is lens-shaped mass of igneous
rocks occupying the crest of an anticline or the

ath, Ai hacolith is Corndon Hi

in Shropshire, E
A bath huge mass of ign
usualy granite, whic A

w Mountains of Ireland

un Fra

West Malaysia. Their precise. mod

still a matter of controversy. It is

that lange masse of magma rising upwards mean:
try rocks with which the nto

etamorphosed rocks together with
the solidified magma give rise to holt,

the most spectacular ofthe intrusive landforms

of Volcanoes

The Oris

The ancient Greeks be

sane eruptions

Mt. Mayon, Philippines, in eruption

where there are zones of weakness due 1

‘oF mountain folding. As temperature increases
with increasing depth below the earths crust, at an
average rate of about I°F for every 65 feet of descent
he interior of the earth can be expected to be i
Semi-molten state, comprising solid, liquid and
ous materials collectively termed mag
The magma is heavily charged with gases sue

carbon dioxide, sulphurated hydrogen, and small
of nitrogen, chlorine and other volatile
and vapour increase the
mobility and explosiveness of the lavas which are
<mitted through the orifice or vent of a voleano
dur There are wo main
types of lanas

1 Basie lavas. These are the hottest lavas about
1,000°C. (1,830°E) and are highly fluid. They are
ark coloured ike basalt rich in ron and magnesium
ut poor in silica, As they are poured out of the
volcano, they flow quietly and are not very explosive
Due to their high fuiity, they flw readi with a
speed of 1010 30 miles per hour. They affect extensive
areas spreading out as thin sheers over great distances
before they solidify. The resultant voleano is gently
sloping with a wide diameter and forms a fatened
Shield or dome (Fig. 27)

voleanie eruption.

Fig. 28 Acid lava cone

a

These lavas are with
ing point. They are ligh-colowed, of
and have a high percentage of ila
stp and seldom travel far before
‘The resultant cone is therefore
rapid congealing of lava in the vent
‘obstrets the flow of the out-pouring lve, resulting
in loud explosions. throwing out many volcanic
bows or porclests (Fig. 2). Sometimes the lavas
fare so viscous that they form a spe oF pls at the
rte like that of ML Pele in Martinique (Fig. 29)
Some spines are very resistant and while most of the
‘material of very old voleanoes i removed by erosion
the spine may remain, eg. Puy de Dome, France.

lava, flowing for long distances produces extensa
rias of Ue Saale Bas, USA. The Co
[eet Dias ad
A |
EEE ne! tos The volearces of |
peti carne tem mes Tho arco
HL alba oie sa da |
fie teal co cad Kins bm a cad
Stcep-walled <a into which the active vent pours
D hola firming the love of Mala na
Towns of lnm fonts cc and fall na
desing

Te Ie Tula nas that explode more vile
[at and code onen ae coal Soa
And see ops They are pi of sal eae
Securing i groups and clio using 189]
fet nigh, sc as Me. Nuovo, nt Noles al
Mt. Paricutin in Mexico. The lava flows are so}
Viscous tha they soy ater a show dane]
Wien thy ae conne in valleys, they form, Dal
nd Idd ls sr à
ir valley. Other minor feature that ne
ascii la obtrctions clude is Me
er ae

À ln non may be stewn with sl
maté ut ere ued ffm he cat of the
sean Te ey fe pris ae ihe lo
Conc ound the word seer tines bere hl
tal cones to et The das oh roe aù

Fig. 30 A composite cone

slow have earned for it the name ‘Lighthouse of the
Mediterranean Other well known composite vol-
canes include Mi. Vesuvius, Mt. Fui, Mt, Popacata-
petland Mt, Chimborazo.

During an eruption material from the top of the
‘cone is blown off or collapses into the vent widening
the orifice into a large crater. Some voleanoes may
have greatly enlarged depressions called calderas
Which may be several miles across. These are the
result of violent eruptions accompanied by the
subsidence of much of the voleano into the magma
beneath (Fig, 31), Water may collect in the erater
or the caldera forming crater or caldera likes eg.
Lake Toba in Sumatra,

‘Some Volcanic Eruptions
In he history of mankind perhaps the most disastrous
eruptions were those of Mt. Vesuvius, Mt. Krakatats
and Mt, Pele.

Mt. Vesuvius
Mi. ‘Vesuvius, standing 4,000 feet above the Bay of
Naples erupted violently on 24 August AD. 79
taking the people who lived around it by complete
Surprise. White-hot lava flowed from parasitie cones,
In the midst of a thundering explosion, the highly
gaseous magma escaped as gigantic luminous clouds
in caulilower form and shot up 10 great heights
before i fell to earth as pyroelasts and ashes. The
city. of Pompeii, located 10 the south-west, was
buried beneath twenty feet of volcanic ashes whieh
were later cemented by the torrential downpours of
heavy rain that accompanied the violent eruption
In a similar way, the city of Herculaneum on the
west vas completely overwhelmed by a mudilow of
ashes and cinders almost SO feet thiek, washed down
bby torrential rain from the slopes of Vesuvius
‘Almost the entire population of the two cities was.
buried alive.

‘Alter this, minor eruptions occurred from time to
time but the fertility of the solidified Voleanic ashes.
tempted many farmers to begin anew on the slopes |
of Vesuvius. Then came the catastrophic eruption
‘of December 1631 when an avalanche comprising
red hot volcanic debris, pasty lava and highly
energized gases ruined fifteen towns and Killed
4000 inhabitants. The ashes that descended on
Naples were estimated to be a foot thick.

Mt. Krakatau
me
a
a
eee
ere
‘were brought down as mud
=

=

‘thirds of the island «

High which drowned 36,000 people in the coustal
dstrcts of Indonesia,

Aller remaining dormant for almost hall à
century an eruption in 1927 pushed up a cinder
cone from the submarine for, culminating in à
Summit of 220 fet above sex level by 1952, This
‘new volcanic island was named Anak Krakstau.
‘meaning the child of Mi. Krakau

Mt. Pelee
‘The eruption of Me. Pelce of the West Inds in
May 1902 was the most catastrophe of modern
times The volcano erupted white-hot lava and
Supecheated scam which swept down the slope
“al an amazing speed as a mice andete (lowing
alanche) St Pire, the capital of Martinique
‘ving on the path ofthe la, vas completely destroyed
within minutes. Is entre population of 30.00,
except two of them, was Killed almost instantly.
Even the sea was boiling and all the ships in the
Harbour were wrecked.

The ejection of oicanic materials continued for
several months uni vertical spine rose from the
‘att almost a thousand feet high by the mide of
1903. The spine was formed by the pasty lava,
partial solid in the nck of the voleano. Part
of the spine, however, crumbled under comtinual
‘weathering aswel as intema ores.

‘Mi: Mayon sean from the town of Legespi, southern Luzon. Philpine Tourist and Travel Association

The Distribution of Volcanoes
the World

Volcanoes are located in a fairly clearly
patter around the world, closely related to n
that have been intensely folded or faulted

are well over 500 active volcanoes and thousands of
dormant and extinet ones. They occur along coast
mountain ranges, as offshore islands and in th
midst of oceans but there are few in the interiors of

atration is probably
popularly te

ey dormant el

Fig. 82 World distribution of voleanoes, lava plateaux and earthquakes

y Islands, but those of ecland
‚tive. Voleanoes of the
region are mainly associated with the Alpi

folds, ez. Vesuvius, Etna, Stromboli, Vulcano and
those of the Aegean islands. A few continue into
‘Asia Minor (Mt. Ararat, Mt, Elbruz), The Hima
layas have, surprisingly, no active voleano at al

In Africa some volcanoes are found along the
Fast African Rift Valley, eg. Mt. Kilimanjaro and
Mt. Kenya, both probably extinct. The only active
volcano of West Africa is Mt, Cameroon. There
are some volcanic cones in Madagascar, but active
ruption has not been known so far. The West
Indian islands Wave experienced some violent ex-
plosions in recent times, eg. Mt Pele in Martinique
And in St. Vincent further south. The Lesser Antilles
fre made up mainly of voleanic islands and some of
them sil bear sign of volcan liveliness. Elsewhere
in the interiors of continents—Asia, North America,
Europe and Australia, active voleanoes are rare

Geysers and Hot Springs
(Goes are Fountains of hot water and superheated
steam that may spout up to a height of 150 fect
from the earth beneath, The phenomena are ass0-
ciated with a thermal or vokanic region in which

the water below is being

(100°C. or 212°F). The jet of water is
emitted with an explosion, and is often triggered off
by gases seeping out of the heated rocks (Fig. 33).

Almost ll the world’s geysers are confined to three
major areas: Iceland, the Rotorua district of North
Island, New Zealand and Yellowstone Park of

Fig, 33 Hot springs and geysers

‘that 60,000 inhabitants died, The effects of the
Mrthquake were felt within a 400 miles radius of
Tishon, in North Africa and Europe.

The earthquake on 1 September 1923 that shook
Tokyo and Yokohama was equally shocking. A
fracture that occurred in the earth’s crust off the
Coast of Japan caused the earthquake. The fragile
buildings of the densely populated twin cities were
mostly ruined; more than half a million houses
ollapsed. Widespread fires from factories, gas
‘mains, oil installations and kitchens killed a quarter
‘of amilion people and many more were injure.

‘Other disastrous earthquakes include that of Sam
Francisco in 1906 wbich ruined the greater part of
the heart of San Francisco, In the loess region of
Kansi in China, the 1920 earthquake claimed
200,000 lives, and again in 1927 when 100,000 cave-
‘dwellers were buried alive. In 1960, the earthquake
‘at Agadır, Morocco sealed the fate of 10,000 in-
habitants, besides causing untold damage, and in
1968 there was a disastrous earthquake in eastern
Iran, with its epicentre at Kaki.

The Distribution of Earthquakes
‘The world’s distribution of earthquakes coincides
very closely with that of volcanoes Regions of
“greatest sismicity are Cireum-Pacific areas, with
‘the centres and the most frequent occurences
along the ‘Pacific Ring of Fire, It is said that as
À many as 70 per cent of earthquakes occur in the
| Gircam-Paciic belt. Another 20 per cent of earth
al > place in the Medterranean-Himalayan

18 Asia Minor, the Himalayas and parts

China, Elsewhere, the earths crust

stable and is less prone to earthquakes,

can be said to be immune to earth

3. Describe. with appropriate sketches, the
major types of landforms originating from acid
and base lavas

4, On a map of the world, locate the chief
voleanie and earthquake areas. Write a des
riplive account of any one major volcan
erupiion or earthquake that has occurred in
historical times. You should include the causes
effets and consequences of such a named

5. The following terms are in one way or
another connected with volcanoes and earth
quakes, Choose one term from each of the
Sections A, Band C and write what you know

About the

Section A Section B Section €
magma basltplateau Volcano
taa Java pla Tsunami
pyreclasts _ parasitiecones “Old Faithful

Chapter 4 Weathering, Mass Movement
and Groundwater

‘The earth crust is constantly undergoing gcologcal
‘changes caused by intemal force, which create new
ese fer, Orns el non mountain
rangos uplift or depression of particular aras is
caused by folding or faulting, and volcanic distur
‘ances also modify the landscape. Meanwhile exter
Pal forces are working vigorously to wear away the
“surface and the interaction of these consructive and
forces gives rise tothe great diversity of
‘present-day landforms. The proces of wearing anay
the earth causes a general lowering and leveling out
of the surface. I is known as denudation and is car
‘ted out in four phases
i. Weathering: the gradual dintgration of
rocks by atmospheric or weather forces;

À Bos the ate enn my of cats

face by moving agents ike running water,

Wind, ce and waves: E

fi. Transportation: the removal of the eroded

__ debris to new postions,

iv. Deposition: the dumping of the debris in
certain parts of the rh, where ü may
accumulate to form new rocks

I for phases ofthe denudation process are tak-
‘Simultaneously in diferent parts of the

Same may weak
seis of the wel

ie ae erysals and weakening ve
Boletines Recon la Malays
grant which his been expose tothe weston
found be and rough This is because the or
aie mad of thee main minas quarts eo
Andi The alzar mor quickly venera ae
the qui and this the (eur eis ave wa
A y nd form couse sandy residue

When the sue of a rock is weathered some of
the material whichis loosened is romonad y cee
Fish surface to weathering, but much of the wea
rel material on regol (emai of the soe) ey
Stayin positon forming the basis of so, Remb
Simply the mineral remains ot decompord eas ut
Sol comas organic materi, suchas the soko
plans, fan les, small animas sch as mora
Bacteria and o on Its the organic content of
Which makes i ele and allovseropsto be porn

When a sol cover exis chemical weathering ol
theunderying rocks does not ease on Le conr À
is usual enhanced, This because the sol aborts
rain and keeps the undoing rock in conan
With dis moisture The ruin-vater absorbs organ
acid from the sol and this becomes à songes
Weathering agen than pure rain-water ating on Dre
rok

There ar thee major chemical weathering proces

(a) Solo. Many minerals are dis by
water specially when, a a te it contains
enough carbon dowd Lo mate La wea ac, Sols
tion he mos poten weathering possi lines
tone regions because the an vater attacks and i
‘ol thecalsum carbonate of which te rook 5
hey fome, The disais calcium carbonates
‘carried away by the water, joints and cracks in the
rock are quickly widened and whole systems of caves

“and passages are worn out ) Limes-
Be (see Chapter 8). Li

it

Maa
| 65
4 i
AMA VE

density of joints rack nt rocks als ruca o
the speed of weathering. This actor is very leary
slaysia inthe weathering of gran In top.
here the hey rainfall and war ch
mate both promote raid chemical reactions we
ring often proceeds very rapidly. This produces the
Very deep regolith or ol overying the solid rocks
‘Often these repos contain corestones These are
pieces of solid rock which have resisted weathering
While all the surrounding rock has been weathered
‘They are more resistant because they hive fener
joints or cracks to harbour moisture and are thus
more slowly weathered by solution processes (Fig.
and Plate A)

Rates of weathering are also affected by climate
Warm wet climate promote rapid chemical weather
ing, while dry late inhibit chemical weathering
Dy climate, however, provide good conditions for
physical or mechanical weathering.

0) Oxidation. Osdation isthe reaction of owen

aor water with minerals the rock. For example,
most rocks contain a certain amount of iron, which

nt comes in contact with air is changed to

Be a

(0 Decomposition by organi als Within he sol
shi covers most rocks are bacteria whch thrive on
decaying plant or animal material. These bacteria
produce acids which, when disolsed in water, Rep to
Speed up the weathering of the underlying rocks In
Some cases micro-organisms and plants hike mosses or
Tichens ean ive on bare rock, so long as the surface s
damp. These absorb chemical elements from the
rocks as food and also produce organic acids. They
fre thus agents of both chemical and mechanical
weathering

2, Physical or Mechanical weather

Mechanical weathering is the physical disintegration
‘ofa rock by the actual prising part of separate parte
‘ex This can happen even with completely fest rock
but the processes of physical weathering are able 10
‘work much more easily when the surface of the rock
has already been weakened by the action of chemical
‘weathering, Mechanical weathering takes place in
several ways,

(a) Repeated. temperature changes. In deserts,
rocks are exposed tothe Blazing sun during the day
And are intensely ated. The outer layers expand
‘much faster than the cooker interior of the rocks and
tend to pull away rom the rest At gal be temp-
erature drops rapidly and the outer Layer contract
{more rapidly than the interior, setting up internal
Streses Such stresses. repeated everyday for months

»

448. nen corestones ro oxposd to topical weather cond
tote they are sabe! ré weg and ving which
‘seth er yarato pa ot Tharsis bade shows
Several lopor hat pi lin some ses. GC Morgan

and year, cause the rocks to crack and split. Well

‘edd and jointed rocks ted to split long the joints
‘oreracks breaking up into rectangular blocks. Shales
and slates may spit up ito plat fragments because
oftheir platy structure In crystalline rocks such as
rate the erysals of the various minerals (quart,
mica, fear) will expand and contract at diferent
tates enhancing the stresses and accelerating the di
integration of the rocks Fragments broken from
large rock outcrops fall by gravity tothe foot of the
slope. They may form sres or may form a iter of
“angular chips and small boulders on the fatter
round,

¡Stress and pressures will naturally be greatest

near the surface and where there are sharp a
the rocks, Rectangular blocks
founded by the spliting away of sharp

the surface layers of rounded boulders gradually sp

led onion peeling, beca

olf the proces is
"asis layers look like the layers of an onion
Df one after another. The technical term
ess exfoliation (Plate 4D),

D) Repeated wetting and drying. Exfoliation is no
confined to desert arcas Similar stresses may be set
‘pin rocks by repeated weiting and drying ofthe sur

tuyere This takes place especially in tropical rey.
ions, like Malaysia, where short downpours saturate
the rocks and then the hot sun quickly dries them
again Repeated wetting and drying also occurs at th
coast, where rocks may be rapidly died by sun and
Wind between tides. When rocks are wetted the outer
layers absorb a certain amount of moisture
expand. When they dry this moisture evapo
they quickly shrink, When this happens repeatedly
the outer layers split off It should also be stressed
that the weting and drying of the rocks in des
probably just as important as temperature char
‘mechanical weathering. The rocks dry very quickly
indeed afer being wetted by brief desert rain-storms.

(©) Frost action. In temperate latitudes frost is a
potent rock breaker. All rocks contain cracks and
joints, or pore spaces, and after a shower water or
snow collects in such places. When the temperature
‘drops at night or during the winter, his water freezes
When water freezes it expands by one-tenth its vol
ume and exerts a bursting pressure of almost 140 kg
Per square em (2000 Ib. to the square inch)
Repeated freezing of this Kind will deepen and widen
the orginal cracks and erevioes and break the rock
into angular fragments (Fig. 42), On mountain peaks
this process ereates sharp pinnacles and angular out-
lines Such peaks are described as fros-shattered

Fig. 42 Frost acon as an gen of mechanical weshering

ter colecta in rock coco.

Water rozes and
‘expands in volume
prising rocks apart

peaks Angular fragments of rock are prised from
mountain-ides or ei faces and fal tothe fot of the
slope where they accumulat to form sre

{@) Biotic factors. Small fragments of rock
loorened by either chemical or mechanical weather
ing lodge in racks and creviss in the rock and plants
may sprout in such creviss As they grow their roots
penetrate the rocks below, usually along joints and
biker lines of weakness prising them apart. You have
often come across large trees growing near roads or
the courtyards of houses that finally prise open the
«concrete or paving stones above their roots. The pro-
‘ess is just the same on a smaller scale in a natural set
ting (Fig. 43)

Men, in the course of mining, road construction
“and farming also contribute to mechanical weh
ing by excavating the rocks and rendering them more
vulnerable 0 the agents of denudation

Mass Movement

Mass movement is the movement of weathered mate-
rials down a slope due to gravitational forces The
movement may be gradual or sudden, depending on
the gradient of the slope, the weight of the weathered
débris and whether there is any lubricating moisture
‘supplied by rain-water, Several kinds of mass move-
ment are distinguished.

1, Soil Crp

This is a slow, gradual but more or less continuous
movement of soil down hilslopes. The movement is
mot very noticeable, especially when the slope i fairly
Rente or when the soils well-covered with grass or
‘ther vegetation, Soil ere is most common in damp

pots un

soi ccumuates
ine walls

‘AC Andi fer food has damaged the rood bata
Penerngan Maya

sol where th water cis as a lubricant so that
val soi parties move or each other and over
the undeying rock. is lo found where continuous
trampling by animals grazing on the slopes ses up
ibrations which losen the sol and cause 10 move
‘Though the movement is show and cannot realy be
seen in action, the gradual movement tts tes,
fentes, posts and so on which ae rooted inthe si
The sls also seen 1 ascumulat tthe (ot of slope
or behing obstacles suchas wal, which may event
Ally be urs by the weight of sil above (Fig. 44).

2. Soi low (Solucion)

When te soli completely saturated with water the
individual parts are almost suspended inthe water
and move easily over one another and over the under
Tying rock. The sol acts ike a guid and a soi fr or

‘mué-flow occurs. In arid regions a mantle of weath
Gred debris may become saturated with

fer a storm and flow downslope as a
mass In temperate and tundra regions soi 1
occur when the surface layers of frozen

in spring. Soil and rock debris lubricated b
water ow easily over the underlying Frozen subse,
In arcas of pea à
ture However if saturation point i reached the peay
foil may flow downslope. In Ireland such

known as ‘bog-bursts

Soils, the peat absorbs much my

3. Landslides (Slumping or Sliding)

These are very rapid kinds of movement
‘shen a large mass of soil oF rock falls sudden!
usually occur on such as in moun
tinous areas, on els or where man has artificial
sleepened slopes, for example, in road or rail cuttings
(Plate 4.C). Landslides may be caused because a
steep slope is "y a river or the sea so that it
falls by gravity ic
may loosen rocks and start of landslide. Man-made
stespening both undercuts the slope and sets up vib
rations which may loosen rocks or soil. But often
landslides re cause by the jon of rain
water. Water may collect in joints or bedding planes
in rocks so that one layer slides over another, espe
cially in areas of tilted strata. Slumping is particulary
common where permeable debris or rock layers
‘overlie impermeable strata such as ey. Water sine
ing through the permeable material is halted by the
Clay. The damp clay provides a smooth slippery sur
face over which the upper layers easily slide (Fig
45).
Water may collect at the base of the regolith
because it sinks readily into the weathered material

Fa 45 Landes

40 Anatomy fpreventin
be Tan oh Cheng Leong

bo mos slowly no the sold rock beneath Te
tearing ie

Manon >
EEE an cover als mor water 10
em the ai and rocks In arcas such a te
Ron Highlands whee sep dope NE hen.
SE er much evidence of minor slumps a
AI ld ers showing u ley nth tur
as ve lndsden ehr natural or man-
iad can ne dus comme Bin.
Ms aay es or people. Spears
M he Alen place many ps ofthe word,
cas South Wales ah Columbia, Hone
ipl Je Cameron Highland where te slo
Mage way par, buried in 1361 and swe
owes wee un,

Groundwater

hehe proms econ of war beten
a ape nova se I

wlan Much of it flows diretly o slopes to fo
Pas and rivers, evennally reaching the seas and
° This known as À considerable
Pe pecoltes downwards into the soil and
Dock. Aline up joins and pore-spaces and forming
hat is known as ‘Groundwater plays an

un ah important asa means of natural ver

TE reenter the hydrological cycle

rigs.
te depends some extent
Sc pation may be quickly evaoraed into
The dy mosphere and ite mature may po
oud avery humid eons where he
SE ound may aredy be mois, much
e oy be moved as ura In moderately Du
e ee path runs off and sinks tothe ground
th opr of the afl absorbed as ground
Tera depend on th seson of he a
Rat Tones de nature of te

available to form round
In dry climates

LE A over o in Kula Kanaan Malays) in 1967
soto tas under 28m (1 2010) of wate

(og. grnte)

99.46. Porosity and penalty of ek

rocks and how casly they absorb and retain water.
Various rocks and sis dile greatly in ther porosity
and permeabiliy: the amount of groundwater pro
Sent and the depth at which it lies are governed by
thee characters Poo rocks are those, lke
Sandstone. which have many pore-spces between
‘the grains. Water is easily absorbed by such rocks and
may be stored in he pore-saces Perse or po
‘ous rocks are those which allow water to pass through
them easily (Fig. 46. Thus most porous rocks are
ho permeable However some rocks are porous but
inpeimesble Clay, for example i highly poros
since its made up of innumerable very tine paris
ones

water. However, Ihe porespaces are so
Sal that the water dos no move casi trough he
ok, impermeable. On the other hand,

numerous joints or cracks through which the wate
an pass rendering it pervious or permeable. Son
rates ae, however, far more pervious than others

The Water-Table

‘Water which seeps through the ground moves down.
ward under the force of gravity until it reaches
impermeable layer of rock through which it cannot
pass If there is no ready outlet forthe grounds
the form of a spring, the water accumulates abo
impermeable layer and saturates the rock The
permeable rock in which the water is stored is knows
as the aquifer (Fig. 47). The surface ofthe saturated
area is alle the water-able The depth of the mater
table varies greatly according toric’ and to the
rocks The water-tale is far below the surface of
hilltops but i close to the surface in valleys and fla

Swampy conditions The depth of the water.
‘aries greatly withthe seasons. When plenty of rain
valable to augment groundwater supplies the wate.
table may rise butin dry periods no new supplies are
available, and the water-table is lowered as ground
waters ost through seepages and springs (Fi. 47)
e.491)Spingseepstromadgeofpeniousrockvingabove
Bine pong tt

Fo Ald) Sep ot sting and pope spring

Springs and Wells
1. Springs

“The groundwater stored nthe oc ssl on
theses at pont where the atea reaches
the ara A oping 6 app an ott fr sch
Mice Te water may ep gradual ut ofthe rock
Srey gah out as Suman. Spies are of seer
tad tote mure of the ook and the poston
Sr tbe watertale The main res are described
Beton:

{@) In areas of led mr, where permeable and
impermeable rocks sete water enges atthe
A a the permed yes (Fis. 48).

Go In Mobil rks water may percolate
dons uni teaches a Jin which meros a
the anno The water may come 10 the suce

through te join (Fig. 4.86)

(©) Where a dyke or sil of impermeable rock is
intruded through permeable rocks it causes the
twatertable (o reach the surface and the water sus

a spin ie 480)
(a) In Imesione or chalk escapen, where the
mate rock les betwech Impermeable stata,

Teter is a the fot ofthe sap a à sari

Spring, or nar te fot ofthe dipslope as a ape

spring sustos in Fig 480
19 In karst regions riers often disappear under-

ground. They then fw trough passage worn in the

‘Eat by salto, and may remercions

‘es place 1 me impermeable esk This Hid of

pein 1 sometimes called vac spring Bat is

Ver refered to a a renonce (Fi. 46; se abo

Chap)

Some oler types of springs eg. hot spring min-

cra springs and pose are described in Chapter 3

S

rn

Fig, 49. Dept of wes nd water table mark

2. Was

Springs are the natural emergence points of ground
Water, but Man can make use of stored water below
ground by sinking wells A hole is bored through the
earth until the water-tabl is reached. The well must
be sunk 10 the depth of the permanent water-table
(Fig. 49) if a constant supply of water
obtained, Ifthe well is only sunk to the wet-scason
depth of the water-table, water will be unobtainable
when the level drops in the dry season, When a well is
bored, the water usually has to be raised by hand or
by mechanical pumping. Wells are particularly
important in arid areas where there is litle surface
water but where the underlying rocks contain ground-

"A particularly important type of wel isthe artesian

Pf fats Wes rok yor bre box Son
Na
en
impermeable layers such a5 day, The porn
BE anime oe at he

sn, du wae aig on them yl gradual
dovnwands by the fore of gravity unt reiches he
Joves part of the asin (ie 4.10, The inpermeaho
ier bel prevents the nie om pasing deve
ands wile the impermeble yer ontop prevents
any pos of te water exaping upvards The
le tus iros to thr of ts bis

"ue water hus app inte quier under get
pre and whens wel is borde pese of
Mae downs fom all around the bain Sul
Sen to Tre the water up the borehole so that
hs ono the sue ike af

P ces to pump up

The depth of artesian wel v
y ates from place to
place, Mom afew Tetto thousands of fet The water
may be used to supply the needs of an entire village as

in the Great Plain of USA, or for sheep farming as
in Queensland and other parts of Australia. F

shows the distribution of artesian wells in Australi
But the water is sometimes unsuitable for agricultural
‘oF ration purposes at may be hot or contain an

QUESTIONS AND EXERCISES

1. (a) Whatdoyou understand by the term weather

natural forces that playa olen weh“

E
=
cie how ginal fos and ir
Jal materias om opos
(©) Disinguh so enep om andes and
Joes pcs whee sch ences fae
taker pic
3. (a) What sein by the lowing
i byes eee
ii suite
Forany mu fabor discusion
pl pandas
(ni here und conse
anges 16 creas no ie, exer eso
uur ae working vigorous feel dom.
Dect
5 Bla on any deo the lowing
sion rod empeturechanges
inde
(Sees came ooo steep moun-
thins intemperate ands
(6) ‘Thar ae min wan which springs canbe
E

‘weathering and give examples of

©

ma
ET
e

Artesian wel are mos valuable to Man when they
un be used in desert areas eg in part ofthe Sahara
and in Australia. The aquifers recive water in areas
of higher rainfall bat the water accumulates in basins
Underlying aid regions.

AU wells bored by Man tend 10 deplete grande
ter resources because the water is extracted faster
than under natural conditions and also much faster
than ican be replenished by rainfall In many areas
groundvater supplies have been greatly reduced or
fren exhausted by Man asa result of eareessess and
‘overexpoitation,

rent from mechanical weathering?
(6) Deseribeany tree major prosesesof chemical
weathering
(0 In what type of physical landform is chemical
‘weathering by solution most dominant?
(a) Name a few wellknown physical festures
‘used by solution in chemical Weathering.
7. (2) Why is mechanical weathering also known as
physical weathering?
(6) Site our ways by which mechanical weather
ing takes place
(6) Inwhatctimatiregionssmechanical weather
ing by fost ation most potent?
8. With reference to examples carefully distinguish
between
(“weather and erosion"
{6) ‘porous rocks and "pervious rocks!
(9 sigan et
(@) ere
9. Describe and explain the manner in which a land
surface may be changed by
wind. e
site your answer with annotated diagrams
and speci examples =
10. (a) Explain what happens to precipitation when
ie als onthe land surface. :
(0 Via on eerie ant of St
tering the ground ina parti
(©) Why isthe "underground senen better del
‘open in karst regions?

nun

Chapter 5 Landforms Made by Running Water

‚The Development of a River System

When rain falls par of it sinks into the ground,
some is eraporated back into the atmosphere and

the rest runs off as rivulets brooks, steams and
tributarios of rivers that fw down to the sea

the earth surface. Denudation isthe general loering
ofthe earth’ surface. This takes place because such
“agents of erosion as rivers ie, wind and waves wear
‘avay the rocks and transport the eroded debris 10
lower land or right down to the sea, But erosion
‘eannot take place unless the rocks ar ist weakened
for shattered by exposure to the elements. Rain,
frost and wind weather the rocks so that they can be
eroded more easily. Unlike glaciers and snow, which
are confined to the cold and temperate latitudes
ses which act only on coastlines; winds, which are
Only ‘fin in deserts; the effect of running water
is fl all over the globe wherever water is presen
Running waters thus the most important single agent

‘The source of a river may be a spring, a lake or
a marsh, but it i generally in an upland region,
Where precipitation is heaviest and where there is a
slope down which the run-off can flow, The up-
lands therefore form the catchment areas of rivers
‘The crest of the mountains isthe divide or watershed
from which streams flow down the slopes on both

sides 10 begin their journey 10 the ooeans. The
initial stream that exists as a consequence of the
slope is called the consequent stream. As the con
Sequent stream wears down the surface by deepening

iy chanel ownvans ond by sort
her obliquely or at right angles depend
nthe alignment an the dare of run of he

This running waterformsa potent agent fordenuding ip, ss

Fig. 94 Dendrite or

ocio
developed on homogeneous rock or beds of
‘equal resistance

drainage pattern

Fi 95 Telsed or rectangular drainage _ pattern
developed on amalng ouzrons of harder
‚and softer rocks. de A

‘The drainage pattern so developed will be rectangular
shape and is called irellised drainage (Fig. 35).

The Mechanism of Humid Erosion
Humid erosion covers the entre scope of seupturing
ti of rang ss fm acon of aa
10 that ofthe rivers. Mass movements of earth and
weathered materials on hillslopes down o alles
are mainly due to the Ibricsting ation of Water
hich allows a mass of materials to move under
ri. This is paru acute where the slopes
are seep. The sow movement of soil down a il
slope is call silerep. A more sudden movement
lc othe lbrcating effet or water may cause

widespread landslides In mountainous discs
here the roads and railway tracks are

ns and even bury

The Processes of River Action
Wen a river lows it caris with it eroded material.

nprise the rivers load, and may be divided

Materials in sollen. These are mineral which
ed in thew

2. Materials in suspension, Sand, silt and mud are

carried along suspended in the water asthe stream

flows

3. The traction load, This includes coarser materials
5 pebbles, stones, rocks and boulders, which

Ihe river bed,

Tt has been estimated that for every square mile
of the earth surface, more than 200 tons of solid
materials in suspension and more than $0 tons of
materials in solution ae being carie off by running
water every year. The Missisippi River which
Urains an area almost hall th size ofthe United States,
itself, removes more than two milion tons of eroded
‘material into the Gulf of Mexico daly. Consequent
ly the river basins ae being lowered, and in he case
of swiflowing rivers like the Irrawaddy, its drainage

3 lowered by about a foot in every 400
y ‘of rock debris
Swept off by rivers is very much greater, We can
See this from the mud that colour the ner

1. Uppar couse a Mss couse

toring sas

such
are rolled alo

ain, The ability of a river 10 move
pends greatly
of the Dow

the various
upon the
and lastly the size, shape
Tes sid that by doubling the i
: 5 by more than 10
transporting power is increase
times! It is therefore not surprising to find huge
boulders that are ‘stranded’ in normal times, But
may be moved during seasonal foods: The move-
ment of river thus intermittent, acting vigorously
in certain parts of the year and remaining les atve

River Erosion and Transportation.
In rivers erosion and transportation go on smül-

tancoush, comprising the following. interacting
processes
1. Corrasion or abrasion, This is the mechanical

singing of the rivers traction load against the
Hanks and bed of the river. The rock fragments a
hurled against the sides of the river and also roll
along the bottom ofthe river. Corrasion takes place,
in two disinet ways

(a) Lateral corasion. This isthe sideways erosion
which widens the V-shaped valley

(0) Vertical comsion. This. the
action which deepens the fiver channel.
2. Corrosion or solution. This is the chemical or
Solvent action of water on soluble or party-soluble
rs with whieh the river comes into contact. For
example calcium carbonate in limestones is easily
{issolved and removed in solution.

3 Lowercouse

food pins
‘owas
om

dounvard

|
|
|
|

O VMS wen genie al) very ey pn, il
Fig. 38 Tho graded long protean typical cross sation of river (ram source to mouth

3. Hydraulic action. This isthe loosen-
ing and sweeping away of materials by the mer water
itll Some of the water splashes against the rer
banks and surges into cracks and crevices. This
helps to disintegrate the rocks The water also
the softer rocks with which it comes
into contact. I picks up the loose fragments from
its banks and bed and transports them away
44 Attriion, This is the wear and tear of the
transported materials themselves when they roll and
collide into one another. The coarser boulders are
broken down into smaller stones the angular edges
fare smoothed and rounded to form pebbles. The
finer materials are carried further downstream 10
be deposited.

‘The Course of a River
‘The course ofa river may be divided ito hr distinct
parts (Fig. 36). 1. The upper or mountain course
(inthe stage of youth), 2. The middle or valley course
{nthe stage of maturity), 3.The loner or plain course
(Gate stage of old ao).

1. The Upper or Mountain Course
This begins at the source of the river near the water-

shed, which is probably the ces of a mountain
range The river i very swift as it descends the
Step slopes, and the predominant action of the ver
is vertical coran. The valley developed is ths
deep, narow and disincvely Vahaped. Down
ating takes place so rapid tat lateral comen
cannot Keep pace In some eases where the rocks
are ery reta, the vay so marrow and the
Sides ae so sep that goes are formed eg. the
Indus Gorge in Kashmir. In arid regions where
there ite rainfall to widen the valley sides and
Abe river cuts dep into the valor, presptous
valleys called camons are formed, eg. the Bryer
Canyon, a, USA.

=. or ousandin tur hat are

en best developed inthe upper course of a river

folowing.

A deep gorge inthe Cuzco Department of Paru Paul Popper

the pirsey occured is termed as the elbow of capture
The beheaded stream (Z) is called the misht. The
valley below the elbow is the wind ap, and may
be valuable as a road and rail route, Examples of
river capture abound. In Burma, the Upper Sitang
hasbeencapiuredbythelrravaddysinNorthumberland,
England, the Blyth and the Wansbeck are beheaded
by the North Tyne.

(0) Rapids, cataracts and waterfalls, 1

Fig. 38 Ropids,catara

greater dimensions are also referred to as cataracts, of

Which there are five along the Nile that interrupt

smooth navigation. When rivers plunge down in a

sudden all of some height, they are called

(ig. 39). Their great force usually wears out a
beneath, Waterfalls are formed in

several ways

Fig. 39 A waterfall ith plunge pool

4. Wen a bar of resistant sock es transversely
across a rer yale, eg. the Niagara Falls USA,
‘which is 167 fst high and the Kaieteur alls ia
Guyana, $25 fet high.

‘When a fauctine scarp caused by faulting
tis across ver. Victoria Falls on the River Zam

Ne uns down the gs of a

feet through a series of more than 30 rapids as
Livin

iy. Glaciation produces where
tributary streams reach the main Usshaped valley

the Yosemite Falls of

se the River Congo which kaps for 900 |

California with a total descent of 2,560 feet.

2. The Middle or Valley Course

In the middle course tends 10
Active erosion of the

place vertical corrasion
the V-shaped valley. The volume of
‘of many tributarios

banks widens

Fig. 4 Intrlocking spurs

and this increases the rivers load. The work of
the river is predominantly transportation with some
‘deposition, Downstream, the interlocking spurs
‘ig. 40) that project from both sides of the valley
are cut back into a line of bluffs Rain-wash, soil
‘reep, landslides and gullying gradually widen the
salle, cutting back the sides The rivers treble task
of valley-cuting, bed-smoothing and debrisremoval
fare being carried out in a more tranquil manner
than in the mountain course though the velocity
does not decrease. Some of the load is dropped or
‘deposited, Again this depends on the volume of
‘How, for in the event of flood, the rivers erosive
power and its capability for load-carrying is greatly
Increased. The more outstanding features associated
‘with the valley course are these i
(0) Meanders. As water flowing under gravity
‘seldom flows straight for any long distane, a winding
course soon develops. The iregularites of the
‘round force the river to swing
meanders, term derived from

Meanderez in Asia Minor. The mechanism
‘meander formation isilstratd in Fe 41.

(0) River lif and sipoff slopes. When the
flow of water PQ (in Fig. Al) enters the bend of the
river, it dashes stright into Q, eroding the outer
‚bank into a step river at Q. The water piles
up on the outside ofthe bend because of the centr
fuga force A bottom current RS is set up in a cork
crew motion and is hurled back into midstream
and the inner bank. Shingle is thus deposited here

at S, where the sip ut
Tank ie ie the bank of continous cro
td the inner bank is the bank of continual He
{© Interlocking spurs. As the stream flows or
the meanders migrate progressively outwards win

an pi
Ati stage that meanders in the middle co
sm one E
bends are restricted by the interlocking spurs In
the lower course, the loops are e a

pian and meanders rfl develope

la
3. TeLoer or Plain Cause
The eier moving downstream across a brad, Ina
pli à hey wih debris brought down (rom the
Upper course. Vertical comson has almost ected
though ners corason sll goes on to

banks further. The work of the river is ma
Sepostion bling up is bed and forming ete
food pans The volume of water is real svg
ty the doa bancs that join the main steam,
oars materials are dropped andthe finer sit
Cat don vars he mou ofthe rer. Lar
sheets of mates are deposited on the level plain
and may split the Ever no sever complicated
ac» hat in be ded as rs
we Sm jor lin course features are

“The Sg. Maar In Negi Sembilan
The iverswings oy sete
lng meander Rothen
ga ios

19. 42 Section of a flood plain (with levee and
minime the risk of foods, arica! embankments
are erected on the natural levees, but this allows the
river to rise Further. When they can no longer with

od water, the banks

1 the pressure of the
aging pro
Disastrous floods of this nat
the Yang-tze Kiang, Mississipi
plains. But the best known river for Moods is the
Fivang-Ho, "China Sorrow’, where milions have
perished, For example, in 1852 the Hwang-Ho
breached ils bank, kiling a milion people and did
untold damage 10 farms and properties The rivers
course was diverted over 300 miles avay, dining
into the Gulf of Pohai instead of the Yellow Sea,
Nowadays huge dredgers help to deepen the channels
10 avoid excessive sedimentation.

(0) Oxbow lakes. These are also known as
utsolfs or baÿous in the Mississippi basin. In the
lower course of à river a meander becomes very much
more pronounced, The outside bend or concave
bank is so rapidly eroded that the river becomes
almost a complete circle. There will come a time
‘when the river cts though the narrow neck of the
loop. abandoning. an ox-bow lake or mortlake
(meaning dead lake), The river then flows straight.
“The ox-bow lake will ater degenerate into a swamp
through subsequent Moods that may silt up the lake.
Te becomes marshy, and eventually dries up Fi. 43).

(©) Delta, When a river reaches the sa, the fine
materials it has not yet dropped are deposited at its
mouth, forming a fan-shaped alluvial area called a

1 drowning thousands
frequently occur in
Po and Ganges

DK es a
Y)

3. 43 The formation of an ox bo lake

ta, a word which originated from the Greek let

A which closely resembled the triangular deta of 1

Nile (Fig. 44), This lluvia tract isn fac, a seaward
extension of the Nlood-plain. Due to the obstruction
fused by the deposited alluvium, the river may
ischarge its water through several channels called
distrbutaris Some deltas are extremely large. For

ance the Ganges deta is almost as big s the whole
West Malaysia, Deltas extend sideways and sca-
rs at an amazing rate. The River Po extends its
dela by over forty feet a year. The town of Adria
located nearly fifteen miles inland was a seaport in
the time of Christ!

Deltas difer much in their size, shape, growth
and importance. À number of factors such as the
fate of sedimentation, the depth of the river and the
Seabed, and the character of the tides, eurents and
ly influence the eventual formation of

Fig. 44 The formation of delas
{a} Stages in ho formation of a deta

ee

1) Section tough the lower course ofa
Fiver showing flood plain and delta

delas For this reason, several types of delta are »)
sible The Minis has a Dino dla

main branches like the Lt of a Bird

the Gall of Mexia. The Nie. Ganges

shifted upwards to the middle course, The upper
course is itl affected when thee is a rise in sea evel
the sea has risen this was

se of water loc

Ne In many areas where
probably caused by the r
Fa ee masses during the Qu

The Human Aspects of Rivers
commerce and transport. The Yangize Kiang is
havigable up to a thousand miles fom is mouth
The Amazon, the worlds greatest river is navigable
2300 miles upstream Lo the foot of the Andes
though itis les extensively used, Even the Nile
wit is catarats is navigable fo is fist 960 miles
Up to the Fist Cataract at Aswan, Other major
rivers such as he Mississippi, St Lawrence, Rhine,
Danube, Congo, Mura. Dating, Mekong and Tr
waddy all serve as important waterways for their
Tespective countries. Some of them are useful for
transporting les tothe saw mills others are used 10
export bulky goods and import foodstulls and raw
material.

But al rives undertake three closely interelated
activites coso, transportation ad deposition. Their
‘work has therefore both advantages and disdvant-
‘ges from a human point of view. Rapids and water
falls interrupt the naviabi of aster By depo
ing large quantities of sediments in the lower course
the river sits up ports presenting large steamers
from anchoring close to the shoes, elias are thus
les satisfactory sites than estuaries forthe siting of
large ports Though this can be overcome by the
construction of artificial harbows or by dreding
this is expensive and, in some instances, imprac
‘able Some rivers change their cours from time
to time, others are made difficult for navigation by
their seasonal variations in the amount of water
scharged, and others may sur fom l-drined
‘marshes and stagnant waters leading tol health
And water-bome disease. Many rivers food, busting
levees and casing untold damage 10 crops The
floods may adda layer of fertile sto the Mood pain,
but excenite Moding as in the Orinoco may di“
courage people from culating cops tall,

‘On the other hand, the advantages of vers
often outweigh the destruction that they cause

In the upper cours,
2 gadis

ed up
may Lee Ages

downstream unchecked may cause widespread dis
astrous floods in the lower course, eg in the
Indus and Ganges plains. In regions of insufcient
rainfall such as Egypt and the Chao Phraya basin
in Thailand irrigation canals fed by the main stream

able many crops to be succesfully cultivated
The upper streams develop river captures and the
resultant wind gaps may facilitate construction of
‘upland roads and railways. The river valleys provide

The
‘mantles of fine silt are some of Ihe richest rica
“reas of the world. They may support very dense
populations and a chain of large cities may be strung
long their banks. Many delas are equally fertile,
ez. the Ganges delta accounts for almost all the
jute grown for world consumption; the Nile delta
produces superior quality cotton and several crops.
of rice a year. The productive hinterlands are able
to support ports such as New Orleans for the Missis-
sippi basin, Rotterdam for the Rhineland and
Calcuta forthe Indo-Gangetic Plain,

‘Fresh-water fishing i important along many rivers
and lakes. The organic matter brought down by
the river waters provides valuable food for fish and
for spawning purposes. Rivers supply water for
domestic consumption, sewerage and other industrial
purposes In Lancashire, the soft-water from the
Milstone Grit is used for washing, dyeing and
bleaching textiles Rivers form the political Daun“
aries between many countries The Mekong se
parates Laos from Thailand; and the Yalu forms a
‘well defined border between North Korea and the
eastern USSR.

QUESTIONS AND EXERCISES

1. What are the characteristic features you
would expect to find in a river valley at the
stage of youth, maturity and old age? Iustrate
some of the more ng features with

following pairs of atures of a iver:
1) dendritic and relie drainage patera
(6) rapids and waterfalls
(©) cstuary and deta
(6) tributaries and distibataries
(©) river capture and rer ci

4, Explain any tre ofthe following statements
“riety:

(@ Mass movement of earth is mainly due
19 the lubriating action of rain water
and gravtiona ores

0) Vertikal corasion is dominant in the

upper course of a river.

(©, The work of the river in the lower course
is mainly depositor

(8) Ports are better sited on estua
on delas

(©) Incised meanders are 1
rejuvenation

ures of river

5. Either: Describe and explain with relevant
sketches the various types of river
delas

Or: Explain the ways in which river erosion

Chapter 6 Landforms of glaciation

The Ice Age and Types of Ice Masses
During the Plistocene period or the
30,000 years ago, great continental
much of the temperate latitudes. It is estimated
that more than 12 million square miles of the northern
hemisphere were buried by ice, half of which was in
North America and the rest in Europe, Greenland
and the high mountains of Eurasia (Fig. 46). The
warmer climate that followed caused the ice sets
16 retreat, Today only two major ice caps are still
present, in Greenland and Antarctica, The former
covers an area of 720.000 square miles while the
Tater is more than $ million square miles They are
made up of compact sheets of ice, hardened and
enysalised to a depth of over a mile In Marie Byrd
Land, Antartica, the ice cap was measured and found
to be more than 14,000 fect thick! Under such a
collosal weight, the land sinks gradually

From the central dome of the ce cap the os creeps
‘out in all directions to escape as glaciers The peaks
of the lofier mountains project above the surface
as nunataks. When the ice sheets reach right down
to the sea they often extend outwards into the polar
‘waters and float as ice shelves. They terminate in
precipitous elif& When hey break into individual
blocks, these are called iceberes While afloat in
the sea, icebergs assume a tabular or irregular shape
“and only one-ninth of the mass is visible above the

Ages about

Fig. 48 The extent of continental co sheets inthe lee Ages

surface. They diminish in size when approaching
warmer waters and are eventually melted, dropping
the rock debris that was frozen inside them om the
sea bed

Apart from Greenland and Antarctica, glaciation
is sl evident on the highlands of many parts of the
‘world, which lie above the snowine This varies from
sa exe in the polar regions to 9,000 feet in the Alps
and 17,000 feet at the equator, as on Mi. Kilimanjaro
Permanent snowfcids are sustained by heavy winter
‘ofall and ineffective summer melting and evapora
tion, Where the slopes are gentle and the hollows
fre sheltered from both direct sunlight and strong
‘winds, any snow that falls rapidly accumulated
Part ofthe surface snow may melt during the day, but
by nightfall itis refrozen, This process is repeated
‘until it forms a hard, granular substance known as.
névé (in French) or fim (in German). Owing. to
gravtational forces, the neve of the upland snowed
is drawn towards the valley below: This is the be
sinning of the flow of the glacier—river of ie.
It normally assumes a tongueshape, broadest at the
source but becoming narrower downhill. Though
the glaciers not liquid, under the continual pressure
from the accumulated snow above, it moves. The
rate of movement is greatest in the middle where there
is lite obstruction. The sides and the bottom are

le of glacial movement. A

er ster in the centre than the

cir moves
6

el bck by tion withthe alley id spurs and
the valley foo, I ow of sakes i planted across
air a stright i, they wil eventually tke a
ured she down th al, showing thatthe lacet
Moves Janer at the centre than the Ses
(Fig 47. In the Alps the wege rate of Bow is
ou thee fet a day in Greenland i may be more
than ity et but in Antartica, wbere thee ite
eat to mel thei place move only a few inches
a day! The Ali Glacier in the Bernese Oberland
of Switzerland is 10 mies long, alor some setae
‘cular sights to Alpine tourists Though it is the
Tongst glace in Europe short compared wi
those of Aaa and the Himalayas which mesure
moe han five ines that ent

‘A the fot of mountain range, several glaces
ma omer 1 rm ete mas all à
pisimon! gis. The best Known pedmont let
Ste Malan Gtr ot Aa a le
long and 25 mies wide, covering an area of more than
1,600 square miles Combined glaciers of such
menso are now rare and in most continents
on alley or Aline glacier are en.

Landforms of Highland Glaciation

Tunes moon wat
=
Begehung

Fg. 48 Development of core

2. ‚Arts and pyramidal peaks. When two corries
ut back on opposite sides of a mountain, knife-cdged
des are formed called aretes (a French word). A
{fel known British example of an arte is the String
> a, ici in Westmorland, Where three or

ques cut back together, their ultimate
‘feesssion will form an angular hom or pyramidal

k. The Matterhorn of Switzerland is a classic
example (Fig 49).

D

Seen

en
en

slope, more revs

Fig. 49 Cirque, arét and pyramidal peak

4 Ushaped glacial trough. The ler on its
D Ba mme eo à
like tributaries that join a river, begins to wear
vay the ides and Sor ofthe val down which
ft moves It scratches and grinds the Bodied
femoving any rock debris and surface soil. I tends
lo Straighten any protruding spurs on its course.
The ineroking. spurs are thus blunted tne
truncated spars and the or ofthe val i deepened
(Fig, 50. A vay which has ten placid ates
a U-shape, with a wide, fat floor
Seep sides Aer the diappearance of the

im ap. sion ofthe
Le

AUshaped valley in Switzerland,
The valle sides are steep but the
floor is fat. There's a ribbon lke
inthe vale bottom

‘Swiss National Tourist Office

in Britain, They are sometimes referred 10 as
‘rough lakes ox finger lakes.

5. Hanging valles. Th ley is

gg valleys. The main valley is eroded much
‘more rapidly than the tributary valleys as it contains
& much larger glacier. After the ice has melted a
ias alley there “ang. above the main
Valley so that its stream plunges down as a waterfall
(Fg 5) Sch ma vals ar med Janis
valleys and may form a natural head of water for
‘enerating hydro-lectrie power.

en oc
sree Tres

PA
Desi Tar ed y ls inthe vall ou,

Where a ru
additional weight

rock step. A series of such ro
der
glacial erosion of the bedrocks

Moraines. Morain
of rock that are shattered by frost action, imbedded
in the glaciers and brought down the val
that fall on the sides of the

m lateral moraines. When two glaciers converge
their inside lateral moraines unite to form

moraine. The rock fragments which are dr
long beneath the frozen ice are dropped when the
cier melts and spread across the foo ofthe valley

are made up of the pices

ay, Those

Fig, 51 The glacial moraines

drops
IF sections break

nic material will only be dropped
y 52. Where the lower end of the
his drowned bythe ca it forms a deep, seep

Fig. 52 A glacier ending att

Landforms of Glaciated Lowlands

Tandforms of glcited lowlands are mainly
depositional in nature, brought about by both walle
aciers and continental ice sheets. The former leaves
behind the eroded materials in only restricted areas.
“The imprint of ce sheets onthe landscape is far more
widespread because they advanced through lange
areas during the Ice Ages, scouring and. removing
any surface soil and rock debris on their way. AS a.
resul, it has been estimated that almost a third of
the total land surface of Europe and North America
is litered with glacial and Muvio-glacial materials
of all descriptions—moraines, boulder clay, ils,
ris rock-flour, gravels and sands. Many of them
fare being re-eroded, resorted and redeposited else
Where by present-day rivers

Most of the glaciated lowlands have depositional
features, but where rock masses projet above the
level surface, thy result in striking features of erosion,
such as the roche moutonnee and erag and tail:
1. Roche Moutonnee. This is a resistant residual
rock hummock. The surface is striated by ice
movement. lis upstream side is smoothed by abrasion
and its downstream side is roughened by plucking,

si

“and is much steeper The term roche moutonnce
i used to describe sch a feature because it resembles
2 shepskin-wig once worn in France (Fig. 55
Roches moutonnees ae found in both highland an
Jontand glaciated regions
2. Ciag and Tal The crag isa mass of hard rock
with a preciptous slope on the upstream side,
thick protest the softer leonard slope from being
‘completely worn down by the on-coming ice It
therefore has a gentle lll, srewn wih the eroded
rock debr The classic example isthe Castle Rock
of Edinburgh, Scotland, Edinburgh Cast is located
fn he cag and the High Stet on the ail. (Fig 4)
The remaining pacated lowland features are of
4 depositions! nature (Fig. 55). The following are
the typical ones
3. Booker cay or glacial ti. Ths is an unsorted
{hacia deposit comprising a range of eroded materials
boulders angular stones sticky cay and fine rock
our. I is spread out in Sheets, not mounds, and
forms genly undulating tl or drift plaine The
landform is rather monotonous and featureless The

deere fe of sh paca pin dope

mach onthe composion of the deposna ma.

ae ae vas such as
1 a the onen Mi

form rich arable lands. o

ae ral That boas of ying sat

ser

Aramsported by ice. They came with the

Fig, 54 Crag and tal
5. Drum. These are 5 Y oval, clongated
= vbaledack:hummocks composed wholly of boulde

day with ther elongation in the direction of the
fee fon: that is on the downstream side. They are
low ills var a few yards to 400 feet in

night and may be

le or two long. They appear
à lie steeper at the onset side and taper of

the Ieewand end. They are arranged diagonally
and so are commonly described as having a basket

ey tap vain toca
Bustin CAE Dorn m Nora cand and ie
Bee Get are ts Nore
ne

& Eier Ths ae long, non, sous rides
lpm inl and el wich ark met
Sis of sega mére sams They ary
from a few feet to 200 feet in height and may be several
mi on. Ine par of Main, USA, te
Sutanding cken frm a conimoos ide 0
100 mile They ae very numerous in Sandia
8 te Panal Esler of Finland, As eles
Ar made wp of highly porous and and rl, oer
i aly dried of fom ther erst and hy
may not suppor many tec, though In Foland
they ain form sete ides Bee kes

7. Termial moras. Thos sr made up a tie

Adrumlin eld in northern England IK. St. Joseph

€.

€ Torm hummocky and hilly country such as the
Bali He Ihe North European Plain (Fig. 55),
$. Outmash plains, These are made up of Musi.
siacial deposits washed out from the terminal
foranes by the streams and channels ofthe stagnant
Ke mass The meltsvaters sort and re-deposi the
material in a variety of forms from the low hilly
peatlands, such asthe Luneburg Heath ofthe North

to undulating plains, where terraces,
1d deltaic deposits of the mel-water
up small
s of sand and gravel may cover part of

European Pla
Streams make
rounded bil

he landscape. Kumes,

pai sition takes the form of
alternating essions, the latter may
contain keule ve rise to chara

tle” topography
The Human Aspects of Glaciated Landforms.

Though the Ice Ages were at their height over
30,000 years ago. the effects of
iandforms and human activities have profound
influence in many parts of the world tod:
most striking impact is felt in the temperate
of Europe and North America which were once under
Continental ice sheets. Further south and on the
high mountains all over the world, slow-moving
glaciers are sill shaping the landscape in the Alps
‘Andes, Rockies and Himalayas. Glacial influences
fon Mans economie activities are both favourable
“and unfavourable, depending on the intensity of
Slacition, the relief of the region and whether the
effets are of an erosional or depositional natur.

In ily regions such as the mountain slopes of
Scandinavia, ie sheets and glaciers have removed

vex
incapable of supporting effective agriculture. Glacial
dis in the valleys and benches or alps which were
not affected by glaciers have good pastures during
Summer. Cattle are driven up to graze on the grass
‘and return to the valley bottom in winter. This form
‘of animalmigration type of farming is called
iranshumance. Extensive boulder clay plains such as
those of East Anglia and the Mid-West of USA.
re some of the mos fertile agricultural plains known,
Ths os pin of Europe and em USA, wi

ith proportion of humus are good farming land to.
‘On the other hand, the sandy or gravelly outwash
pins eg, the heath-covered geese of northern Ger.
‘many, the marshy boulder clay deposits of central
Ireland, the barren icescoured surfaces of the
Canadian and Baltic Shields are infertile The

Fig. 55 Glacial depositional festures in the outwash

presence of numerous eratis and perched blocks in
parts of Britain and in Alberta, Canada, many of
them of giganti size obstruct farming and the use of
machines. Morainie deposits may dam, or glaciers
may hollow out, lakes which greatly inconvenience
farming or land development. But when
re eliminated, the old glacial lake beds
‘vith their rich alluvium support heavy cropping.
Large lakes formed by former glaciation, e. the
Great Lakes of North America, make excellent

Waterways They may also cut deep overflow chan-
nels while draining off, making natural 1outewa's
across a mountainous terrain eg. the Hudson-

Moh Gap tha inks the interior with the Atlantic
aboard of USA, On the otber hand in regions
‘where drumlins are dominant, the drainage is ether
oor or much confused,

Terminal and recesional_ moraines comprise
coarse materials of ite us o man but Auvo-glacal
deposits ar not without their esonomie signieance-
In Ihe outvash pains, eıkrs and Lames have Been
cxeavated to provide sands and gravels or hi
Sind. building. construction. The. purest sands are
rated to make moulds for metal castings The
fake basins of glcated mountains provide natural
fesenois In countries Ike Scandinavia, Switzer-
Hand and Canada where tere ile available coal,
Streams and waterfalls that plunge down from hanging
Salley or othe cite uplands are being harnessed
to provide Iydro-esenie power. This has helped to
el many of the chemical and metalurgkal
indunris With the magnlient scenery provided
by the glated mountains eg. the French, Malian
and Swiss Alps large numbers ol tourists are tracto
to them anna Sin, mountain climbing and
Sightseeing ar al poplar with Alpine tours

PERTE

QUESTIONS AND EXERCISES

1. Choose any thee of he following glacial
features cori, arte, erat, hanging vall
et ak, nunatak. Foreach of them:

(a) Describe is piystal appearance

(0) Account fr its mode of formation

(©) Locate and name an ares where an

example ould be sen.

2. (a) Distinguish hetneen valley glacier and
continental ice sheets.

() Explain why glaciation inthe uplands
produced erosional features while that of the
lowlands produced mainly depositional features

3, De ining loan ei fc ae
nc, amade bat are qui dierent a
{bir roots of formation:

(a) Site wich of tem are of enninal or
depostional ar.

(0) Pick ou their distinctive diles in
oh apprarane and formation.
roc moutons drum, ss
and kame de

4. Briefly explain any thee ofthe following
(a), Glaciatd valleysassumea characteristic
U-shaped.
(6) The middle of a glacier moves faster
than the sides.
(e), Inglacited lowlands, ekers kames and
‘other moranie deposits are extensively quarried,
(0) Glacial sols vary greatly in their fer
(e) Erratics and perched blocks are he best
indicators of the source and direction of ice

5. With the a of diagrams attempt to ©
the difernce between any re ofthe following
pairs of terms connected with
(a), Valley glacier and piedmon
(6) Bereschrund and crevasses
(©, Corrie lake and ribbon lake
() Interlocking spurs and truncated spurs
(©) Terminal moraine and recessional mo-

Chapter 7 A

‘Types of Deserts
About fifth ofthe world’s land is made up of eset,
Some rocky, others stony and the rest sandy. Desert
that are absolutely bare

all are rare and they are better known as “rue

deserts

IF you look at the wo
find that there sa certain
tion of the world’s deserts You will realise that
almost al ie deserts are confined within the 15°10 30°
parallels of latitude north and south of the equator.
They lien the trade wind belt onthe western parts of
s where Trade Winds ae ofEshore They
«3 y cold currens which produce a ‘desi

1d map carefully, you will

or Desert Landforms

into precipitation, Dryness or acidity isthe key note
Such deserts are tropical hot deserts or Trade Wind
deserts, They include the great Sahara Desert
‘Arabian, Iranian and Thar Deserts; Kalahari, Namib,
and Atacama Desens: the Great Australian Desert
and the deserts of southwest USA, and northem
Mexico. In the continental interiors of the mid
Tatts, the deserts such asthe Gobi and Turkestan
are characterised by extremes of temperatures
The work of winds and water in eroding elevated
uplands, transporting the worn-oI materials and
deposit them elsewhere, has given rise 10 five
distinct kind of desert landscape
1. Hamada or rocky desert. This consists of lange

MARS of bare rocks, sept clear of sand and dust
by the wind. The exposed rocks are through
‘smoothed and polished. The region is bare a

“Serle The best known rocky deserts are those of
‘the Sahara Desert eg. the Hamada el Hom, in
hich covers an area of almost 20,00 square

H

or any desert. Tis is composed of ex
ff angular pebbles and ganc which
po ale 10 low off Such stony
"more ases than the sandy
ers of same are kept there In
the term sir ual: eer in.
deers ar cal re
or sandy desert. Tiss ea of sand which
the popular is of dese seen. Winds
‘epost vs reiches of undulating sand dunes in the
hear ofthe deserts The intrite pates of ipl
nthe dune surfacing edition ofthe winds
‘The Cala Sand Ses in Libya is characters of
a sandy dese In Turkestan, sandy deserts ae aso
non as hou.
42 Badlands. The term hadlands was is given to
an aid aa in South Dota, USA, where the ils
‘were badly eroded by occasional rain-storms into
falls and ravines The extent of water ation on
‘ill slopes and rock surfaces was so great that the
‘entire region was abandoned by the inhabitants,
Ds wh i ers to fred ws
za ‘eg. the Painted Desert of Arizona, which.
‘ies southeast ofthe Grand Canyon ofthe Colorado

11M
Hi
a

He

dr Eo nul
on. set up reses in the already weakened
ee SS
one

Fe ee ae mc ives te
ee
eS de

Wind eran i cared out inthe flowing ways
1. Delon. This insoles the Ming and loving
diy of lose mateals fiom the ground. Such
Snconsalted sands and pebbles may be cried in.
the ror rolled along the round depending on the
fn size The fcr dust and sands may be removed
ils ay om thei plas of orn, and be deposed
Sen ous the desert margins Deatlon ress
in the fering ofthe land surface to form lar
prion wid stn Jl The Quien
Depron ofthe Sahara Der sl

Drs of he Sahara Des es lon 150 fet

2, „Amen. The sand
winds when they hurl sand particles against them
14 particles against the

fof rock surfaces

o - The impact of such bis
‘oan rc big rc, ash and
a Ata cox eto the

ee

3. Attrition, When wind-borne particles roll against
One another in colision hey wear each other ay’
that their sizes are greatly reduced and grains are
rounded into millet seed sand, This process is called

Landforms of Wind Erosion in Deserts
abrasion, deflation

Im the combined processes of

and attrition, a wealth of characteristic ds

1. Rock pedestals or mushroom rocks: The sind:
blasting effect of winds against any projecting rock
masses wears back the softer layers so that an regular
«3 on the alternate bands of hard

Soft rocks. inthe rock
Surfaces, carving them into fantastic and grotesque
looking pillars called rock pedestals (Fig. 56). Such
rock pillars will be further eroded near their bases
where the friction is greatest. This process of under
cutting produces rocks of mushroom shape called
mushroom rocks or gour in the Sahara

edge is fora
es an oll EA

Fig, 56 Rock pedestals or gour
2. Zeugen. These are tabular masses which have à
layer of soft rocks Jing beneath a surface layer of
more resistant rocks, The sculpting lets of wind
fbrasion wear them into a werd-lookine ‘ridge and
furrow" landscape. Mechanical weathering iiites
thei formation by opening up joints of the surface
rocks, Wind abrasion Further as into the under-
sim softer aye so that deep furows are developed
“The hard rocks then stand above the furows as rides
or zeugen (Fig. $7) and many even overhang, Such
tabular blocks of zeugen may stand 10 to 100 fet

‘te sunken furrows. Continous abrasion by
gradually Toners the zeugen and widens the

Fig. 57 Zeugen (with horizontal strata of herd and
Sat rock)

Fig. 58 Yardangs (with venical bands of hard end
re)

Yardangs. Quite similar t the ridge and furrow”
landscape of zeugen are the steepsided yardangs
Instead of lying in horizontal strata upon one another,
the hard and soft rocks of yardangs are vertical bands
and are aligned in the direction of the prevailing
‘winds Wind abrasion excavates the bands of sofler
rocks ino long, narrow corridors. separating. the
‘eepesided over-hanging ridges of hard rocks called
yardıngs (Fig. 58). They are commonly found in
the Atacama Desert, Chile, but the more spectacular
ones with yardangs rising 10 25-50 feet are best
eeloped in the interior deserts of Central Asia
‘where the name originated
À Mesas and buttes, Mest is a Spanish word
meaning table’ I is at, tabe-ike land mass with
3 very resistant horizontal top layer, and very steep
des The hard stratum on the surface resists
denudation by both wind and water, and thus protects
the underlying layers of rocks from being eroded
away. Mesas may be formed in canyon regions eg.
‘Arizona, or on fault blocks eg. the Table Mountain
of Cape Town, South Africa. Continued denudation
through the ages may reduce mesas in area so that
they become isolated fla-topped hills called Buttes
Many of them in arid countries are separated by
deep gorges or canyons (Fig. $9).

El

Fi. 69 Mesa and bute

5, Imelberg. This is a German word meaning
“and mountain. They are isolated residual hills
‘xing abruptly from the level ground, They are
éharsteried by ther very seep slopes and rather
sounded tops They are often composed of granite
or is, and are probably the relics of an original
Plateau which has been almost entirely eroded sv
Inslbergs ae typical of many desert and semi-arid
landscapes in od age eg, those of northern Nigeria,
Western Australia and the Kalahari Desert (Fig, 60),

6, Vemilacs or drekanter. These are pebbles

faceted by sand-bstng They are shaped and

‘Ayers Rock, an inselberg inthe Australian Desert Australian Tourist Commission

Fig. 60 Roundtopped, steop-sided inselborge

thorohly plished by wind abrasion 10 shape
‘eng Bu ms Rk ens mean
Weuhered from momias and upstanding weh
fre mo by wind and smoothed on the windand
$i If vind dition changes another Th x
developed, Sich rocks have characterise A fc
With sharp edges Aisa be vecs tose vi
tice vindacid sus ane called kann
Thos ind act pebbles orm the dst ps,
a smooth, moi region, closely covered y the
mers rock fragments and ee

7. Delon bls, Winds lower the ground by

action of on-coming winds will wear off the weaker
rocks until the water table is reached, Water then
seeps out forming oases or stamps, in the deflation
hollows or depressions. The Faiyum Depression in
Egypt lies 130 feet below the sea level, Large areas
in the western USA. stripped of their natura
vegeation for farming, were completely déflted
‘when strong winds, moved material as dust-storms,
laying waste crops and creating what is now known
as the Great Dust Boul. In a duststorm, winds

may lift dust hundreds of fo
thousand

Landforms of Wind Deposition in Deserts
Materials eroded and transported. by winds: must
come to rest somewhere, The finest dust travels
fenormous distances in the air, and may be moved
ut of the desert. It has been estimated
that some dust grains travel as far as 2,300 miles
before they are finally deposited on land or sea. The
dust from the Sahara Desert is sometimes blown
across the Mediterranean to fall as “Hood rains’ in
Italy or on the glaciers of Switzerland. Dust that
settles in the Hwang-Ho basin from the Gobi Desert
has accumulated over past centuries 10 a depth of
several hundred feet! As wind-bore materials are
Sifted according to their coarseness ican be expected
that the coarser sands wil be 100 heavy to be blown
out of the desert limits. They remain as unes or
ther depositional landforms within the deserts
themselves. Since they are rarely static their mit
ration pattern depends on a number of factors: the
size of the particles they cary, the direction and
‘elocity of the winds, the location and nature of the
Surface over which the particles are transported and
the presence or absence of water and natural vege-
tation

“The following are some of the major features of
wind deposition.
1. Dunes, Dunes are, in fac, ls of sand formed
by the accumulation of sand and shaped by the
movement of winds. They may be active or Ive
‘June, constantly on the move, or inactive final dunes
rooted with vegetation. Dunes are most well repr
Sented in the ent desert where a sea of sand is being
Continuously moved, reshaped and redeposited into a
variety of features. Because of their great contrast
in shape, size and alignment, they have been given à
Jong list of fanciful names, such as atached dune or

‘completly o

head dune, tail dune, advanced dune, lat
bolic blow-out dune, hairpin dune, smoking dune
the following. two

will be

dune.

wake dune
par

types of common dunes
described in more detail
(@) Barchan. These are
shaped dunes which occur individually or in
They are live dunes which advance steadily before
winds that come from a particular prevailing direction
They are most prevalent in the deserts of Turkestan
and in the Sahara. Barchans are iniisted probably
by a chance accumulation of sand at an obstacle, such
15 a patch of grass or a heap of rocks. They oocur
transwersly tothe wind, so that their hors thin out
and become lower in the direction ofthe wind due to
the reduced. fitional retardation of the winds
around the edges. The windward side is comes and
entsloping while the leeward side, being sheltered,
IS concave and steep (the slip-face) (Fig. 61). The
Crest of the sand dune moves forward as more sand is
accumulated by the prevailing wind. The sand is
“riven up the windward side and, on reaching the
‘rest slips down the leeward side so that the dune
‘advances. The rate of advancement varies from.
25 feet a year for the high dunes measuring up to

future position of the barchan
Fig. 61 Crescent sand duno—barchan

100 fet high, 10 50 fet year, forthe Tower dunes
whch maybe only. dozen fet high,

"The migration of the barchans may be a ANA 10
desert fe for they may encroach on an oasis burying
palm trees or houses Long-moted sand-holding
Tree and praises are therefore planted to halt the
advance of the dunes thus preventing areas of fer
Hund from being devasated. Under the action of
Winds, barchans take a chaotic changing pattern.
‘Several barchans may coalesce int ine of regular

s

Hide everchanging wih the direction of the winds
Er or sandy deserts are thus most difieult 0 cross

o) Sails or Initial dames. Si is an Arabic
‘word meaning ‘sword’. They are long, narrow rides
‘Of sand, often vera hundred mies long ying pls!
to the direction of the pri winds The high,
‘erated ridges may attain a height of over 200 feet.
The eresline of the si ses and falls in alternate
“peaks and saddles in regular sucesion like the
teeth of amonstrous sa The dominant winds blow
ait along the corridor between the ines of dunes
o that they are opt clear of sand and remain
smooth The ees that are set up blow towards the
‘sides of the corridor, and, having less power, drop
the sand to form the dunes In this manner, the
_prenling winds increase the length ofthe dunes into
tapering linear ridges while the occasional cross
winds tend to increase their height and width,
Extensive si dunes are found inthe Sahara Desert,
south ofthe Qatar Depresion; the Thar Desert and
the West Australia Desert (Fig. 62).

wind-borne dust from the Gobi Desert is caligy
sang — the yellow earth! But the original ter
ess actually comes from a village in Alsace, Franz
fearing that name, where such deposits occurres
‘Similar deposits also occur in some parts of Germany
France and Belgium, and are locally called inion

They are also wind-borne but were blown from
‘material deposited atthe edge of ice-shcets during the
Tce Ages In parts of the Mid-West, US.A. loess vag
derived from the ice sheets which covered northery
North America and is termed adobe

Landforms due to Water Action in Deserts
Few deserts inthe world are entirely without rain op
water, The annual precipitation may be small, $
10 10 inches, and comes in irregular showers But
thunderstorms do oecur and the rain als in trrentil
donmpours, producing devastating effets. singe
rainstorm may bring several inches of rain within a
few hours, drowning people who camp in dr
streams and flooding mud-baked houses inthe oases
‘As deserts have lle egettion to protect the surface
soi, large quantities of rock wastes are transported
in the sudden raging torrents, or flash-floods. Loose
armel, sand and fie dust are swept down the hill
Sides. They eut deep ules and ravines forming
hadland topograply, Subsequent downpours. widen
and deepen the gullies when they wash down more
soft rocks from the surface. There is so much
Material in the lash floods that the flow becomes
Liquid mu. When the masses of debris are deposited
the foot ofthe hill or the mouth of the valley. an
Hal con or for “dy del’ i formed, over
wl lemporary stream discharges through
ene al an ei
paty alluvial deposit are subjected to rapid evapora
don yh hot sin and dowawar proton of
Merino the porous ground and soon dy up ein
Apart from gullies there are many larger di
anni or valleys These ar depen by vera
Gorrason by raging torrents during the occasional
Ioulbursts Thee ae the adi ad are dy for most
Of the time, Some desert streams are fed by the
ling snow of the distant mountains outside the
Asserts and rivers flow as Soll seams The water
ars out steep wall, which rise abruptly from the
SE Tn Algeria such gorges are termed

internal. Sometimes
‘water collected in a depression or a desert basin docs
‘ot completely disappear by evaporation or seepage,

And a temporary lake is formed. Such lakes contain
à high percentage of salts, because of high evaporar
tion, and are glistening white when they dry up. The
Takes and the alluvial plains formed by them are
called playas, salinas or salas in the United States
and Mexico, and shots in northern Africa (Fis. 63).

The floor ofthe depression is made up of two features,
the hafada and the pediment. The bajada is a de

positional feature made up of alluial material laid
down by the intermittent streams. The pediment is
an erosional plain formed atthe base of the surround
ing mountain scarps

QUESTIONS AND EXERCISES

1. Draw annotated diagrams and explain very
briefly any thre ofthe following desert features

(a) yardangs

(0) barchans

(© pediments

(4) inselbergs

(© wadis
2. Attempt a simple classification of deserts
Just your basis of classification by bringing
out their distinct diflerences in appearance,
formation and outstanding features

3. With the aid of diagrams, explain the major
iterences between any three of the following
pas of desert landforms.

(a) zeugen and yardanss

(6) mesas and insebengs

(©) crescenio barchans and longitudinal

si
(4) bajadas and pediments
(e). ventfacis and dreikanter

4. Explain concisely the processes of deflation,
abrasion and deposition by winds With the
aid of diagrams explain mo topographical
features formed by any two of the above pro

5. The following terms are closely related to
desert landforms, For any four of them, define
‘with reference to examples what the terms mean.

(a) erglandscape

(6) loess deposits

(©) badland topography’

(8) rock pedestals

(©) Great Dust Bowl

(0) flash floods

Chapter 8 Limestone and Chalk Landform Baier its re

Limestone and Chalk femeasuioace
imestone and chalk are sedimentary rocks of ore H the isolated, rect A
‘origin derived from the accumulation of corals and H The limestone pavements may have been formed
Shall in the sca. In ts pure tate, limestone is mad teneath the soil and are now exposed by the removal
tp of cale or calcium carbonate, but where magne ofthe soil cover (Fig 64),

On the surface of the limestone are mumerous

mite. Chalk

See pan ro ese, te ad rater 4 covers

rin dose from thea forms a weak acid. À ] :

fen wih a lage sch of Imeone there Gaping Ohyl in Yorkshire ia fine example

ses a ven disc pe of topography. I hse holes row In sie through continuous solve

then td a kant gum, à name deed fom action es:
} I
i

Slum is alo present it à termed

the Kart dic of Yogoshnia where such topo-
rap parier well developed may be as large as a hundred square miles but

Characteristic Features of a Karst Region
Generally speaking, karst regions have a bleak
landscape, oscsionally broken by precipitous slopes

caverns and passages along joint o
cto During the rainy

‘are partly d
parts of the floor which are at or near the water

round tunnel collapses, a

o 0 such as the Chedda

ed. Where a number of sallow holes
is called

precipitous
Gorge is fo I may become temporary lakes, but the drier

1 may support large villages
Ian streams descend. through

areas are fertile

doline (E

Where subi

here general senc of surface drainage as most
othe surface water has gone underground, Streams result of subsidence to form al swallow holes 10 underground passages the reg
an uvala. Some of them area mile across e "ay be honeycombed with cuves and carerns, some
tacular

containing ponds and lakes. The most
derground features that adorn the limestone eaves

tng on eros cn ow ve encor a
thor alan ad thn app undersea. Fr
th er pt he cou ty ct sy
al jos nus othe ken ota
Sse fener channel The sur al
oe ‚dry. When the water penetrates to the Fe ms
of the limestone and meets non-porous rocks it Bern
remeros sg or
Linens val Jo an o
th Jus an rc nner fds lua
into the underlying rock, Progressive widening by
Aino
on caren Note tah

much clayey soil from the limestones,
after their subsidence.

In Yugoslavia, some very

fare stalactites, stalagmites and. pillars Si

Fig. 65 Limestone sconery

Fig, 64 Limestone pavement

al cultivate but the limestone is bleak and roeless

are the sharp, slender, downward:-growing pinnacles
that hang from the evervofs The water carries
calcium in solution and when this lime<harged water
‘evaporates, it leaves behind the solidified crystalline
calcium carbonate As moisture drips from the roof
{trickles down the salctite and drops tothe for
where calcium is deposited to form stalagmites
‘They are shorter, fatter and more rounded. Over a
long period, the staactite hanging from the root is
‘eventually joined to the stalagmite growing from the
floor 10 form a pillar (Fig. 6). Such features are
‘commonly seen in any welldeveloped_ limestone
nes eg. Batu Caves, Koala Lumpur, Mammoth
‘Caves, Kentucky and Carlsbad Cave, New Mexico,
in USA. and Postojna Caves, Yugoslavia,

The Major Limestone Regions of the World
‘The most characteristic stretch of limestone occurs
in northwest Yugoslavia. Other regions include:
the Causes district of southern France, the Pennines
of Britain, Yorkshire and Derbyshire in particular
the Kentucky region of the United States, the Yucatan
Peninsula of Mexico, the Cockpit County of Jamacia,
and the limestone ill of Pets.

Human Activities of Karst Regions

Kant regions are often barren and at best carry
3 thin ayer of soil. The porosity of the rocks and the
absence of surface drainage make vegetative growth

Fi. 66 Limstone cave

dy vay

A dry valley inthe chalk region of southern England

dificult, so that limestone can usually support only
[poor grass and short turf; some sheep grazing is pos
ble. Limestone vegetation in tropical regions. how
ver is luxuriant because of the heavy rainfall all the
Year round. Settlements are scattered and the
Population is often sparse. The only mineral of
importance is ad which occurs in veins in association
with limestone. Besides this, good quality limestones
fare often used as building materials or quarried
for the cement industry. In West Malaysia, the

limestone outerops of the Kledang Range and the
Main Range are quid forthe Pa
Cement Works.

Malaysian and Task

ncepound mern formes
ren na one of weak

Chalk
The landforms of chalk are rather diferent from
those of other limestones. There is litle or no surface
drainage and valleys which once contained rivers are
now dry. These are often called coombes The

‘halk forms low rounded hills in southern and south

in northern France. The chalk is covered with short
turf, and in places with woodland, and is used for
pasture and sometimes for arable farming. Because
OF the friable nature of the rock, svallow-holes and
underground cae networks do not generally develop.

QUESTIONS AND EXERCISES

features oa karst
ams describo thei

1, Choose shee outst
m. With the aid of dia
“appearance and explain how they have been
formed

2. The following features are associated with
karst topography
(a) Clint and grikes

(0) Dolines and uvalas

(6) Stalactites and stalagmites

For any two of them, with the aid of

annotated diagrams, explain their origin and
in actual example ofeach

3. Explain why:
(a) Kant regions have very litle surface
rain
(6) Subtera
sent underground scene
(©) Limestone areas hive litle ag
ed

an srcams produce a magni

and are sparsely peop

4. With the aid of labelled diagrams, describe
and account for the development of physical
features which result from the action of water in

a) limestone regions

(b) arid deserts

(e) granite uplands

5, Draw a large diagram of a karst region and
indicate the following: swallow holes, limestone
gore. dry valleys, limestone pavement with
ciims and grikes Describe briefly how any
‘woof them have been formed,

Chapter 9 Lakes

je the
Take mor e el tr
o se

formation. The tiny ones are no bigger than ponds
Or pool but the age ones are so ees tai he)
pert the name of seas eg. th Caspian Sex which
7 ies long. as muchas 3215 et dep, witha til
tea of 143,550 square mies, and bigger than the
‘hoe of Mal

Lakes may exist temporary ling up the small
depressions of undulating ground afer a Boy
Shower But thse which are deep and carey more
water than could ever be evaporated remain per
Inanent, Most of the lakes in the word ae rs
tater aes fed by vers and without Aoaing streams
2 Lake Geneva, Lake Poyang and be Great Lakes
‘of North America, In regions of low preiitation
and intense evaporation where there are few ners
one enough to each tb sa, steams drain ino
4 lke forming a basin ol inland drainage. Because
Of the intense evaporation these lakes are saline
For example the Dead Sea has salinity ait conten)
of 250 pat pr thousand, andthe Great Sat Lake of
‘Utah, USA. has salinity of 220 parts pr thousand
But, the Black Sea, into which drain many large
fiers, has a salinity of les than 17 parts per thou
Sand! Playas or sal lakes, ae à common feature
older,

must be pointed out that es are oly temporary
features of the earths crust hey wi eventually be
eliminated by the double process of draining and
siting up In regions of unreliable rafa, lakes
‚dry up completely during the dry season. In the hot
‘deserts lakes disappear altogether by the combined
Process of evaporation, percolation and outfow,
hough e res of le lation my not e
completed within our span of life, it takes place
relsivey quickly in terms of geologeal ine, À

The Formation and Origin of Lakes.
The lowing ae, de ar van sh

med. Each of them is paced ing
though in afew ess the lakes could

rpresions occur. Such depresions give rise tg
unen snes and depths They Int
Take Titicaca, occupying a huge depression inthe
Hermon plateau of the Andes, 12.500 fet abene
Bee the highest lake in the word; and the
plas Sea, 143550 square miles, the largest lake
ios 5 times larger than its nearest rival, Lake
Superior

To), Rit valer lakes, Due to faulting, à sin
sale is formed By the sinking of land between two
Parallel faults dee, narrow and elongated in charac
{ex Water cols in these troughs and their Noor
tre often below sea lvl. The best known example i
ihe East African Rift Valley which runs through
Zambia, Malawi, Tanzania, Kenya and Ethiopia
and extends along the Red Sea to rue and Jordan
Ger a total distance of 3,00 miles Ir includes
Sich lakes as Lakes Tanganyika (4,700 fect dep
the world’s deepest lake), Malawi, Rudolf, Edvard
Alber, as well as the Dead Sea 1,286 fet below
mean ses level, the worlds lowest lake (Fig. 67).

Fig. 67 Earth movement

2 Lakes Formed by Glaciation
(a) Cirque takes or tarıs. A glacier on its Wa
‘down the valley leaves behind circular hollows inthe
heads of the valleys up in the mountains Such
Hollows are the arm-chair-shaped cirques or corries
Thr overdecpened foors may e filed wih Yale
to become cirque lakes e. Red Tar in the Engin
District (Fig. 68). Those that occupy glacl
{ous are long and deep and are termed ribbon ake
68 Lake Ullswater
(6) Kettle lakes. These are depressions in the

Blea Water in Westmorland, England, a typical cori a

IK St Joseph

Fig. 68 Glaciation

‘outwash plain left bythe melting of masses of stagnant
foe They are iregular because of the uneven
morainie surface and are never of any great size or
‘depth eg. the meres of Shropshire in England, and

the ketle-lakes of Orkney in Scotland
(0 Rockhollow lakes. These are formed by
ers or ie sheets scoop

‘out hollows on ıhe Si
‘isin are abundant in Finland, indeed the Finns
all their country Suomi — the Land of Takes It
À said that there are over 35,000 glacial lakes in
Finland!

(0 Lakes due to moraiic damming of valleys.
valley alacies often deposit morainie debris acros a
Nes so that lakes are formed when water accumu-
Les behind the barrier. Both lateral and terminal
Moines are capable of damming valleys eg. Lake
Windermere of the Lake District, England,

o

explosion the top of the cone may be blown off
Teving behind a natural hollow called a crater
“This may be enlarged by subsidence into caldera
‘These depressions are normally dry, bounded by
step ci and roughly circular in shape. In dormant
‘or extinet volcanoes, rin fll straight into le crater
fr caldera which has no superficial outlet and forms.
a rater or caldera lake The oustanding ones are the
(Grater Lake in Oregon, USA. which in fact occupies
a caldera; Lake Toba in northern Sumatra and Lake
“Avermus near Naples (Fig. 69).

eked lakes In volcanic regions a
ay ow a aval eh

riverforming a lake, lava

the Jordan valley forming the Sea of

Vis an Inland Tak, rather elongated

Fig. 70 A karst lake formed above the ground water
table in a limestone region.

a
Intex Exceso evaporation causes these to become
A sae
pe enc.
oe ote
oe won
EL es ered
cael Sell only by a marron spit of ln
deltas of large rivers such as the Nile and the Ganges.
ee eres:

coastal sand dunes landwards, and these may enclose
marshy lagoons. This type of lagoon is well deve
Hope in the Landes of south-west France

{Lass duc o landslides, seres and avalanches
Lakes formed by these processes are also known as
barrier lak ay block valleys
so that rivers are dammed. Such lakes are short
five, because the loose fragments that pile across
the valleys will soon give way under the pressure of
water. When they suddenly give way, the dammed
Water rushes down, causing foods. Examples of
Takes of this type are, Lake Gormire in Yorkshire,
locked by landslides; Ffynnon Frech on Snowdon
blocked by sers (Fig. 71).

Fig. 71 Deposition (a barrier lake formed by the
‘eposition of an obstacle)

a lake made by constructing
vor valley)

Fig. 72 Human activites
‘concrete dam across

6. Lakes Formed by Human and Biological Activities
(a), Man-made Takes, Besides the natural lakes
man has now created artificial lakes by erecting a
“concrete dam across a river valley so that the river
water can be kept back to form reservoirs Fig. 72)

Amongst such man-made lakes, the most imposing
is Lake Mead above the Hoover Dam on the Colorado
River, USA.

(6) Lakes made by animals. Animals like besser
are particularly interesting. They ive in communities
and construct dams across the rivers with timber,
Such beaver dams are quite permanent and are found
in North America, eg. Bewer Lake in Yellowstone
National Park, USA.

(© Other types of lakes. These include omamen-
tal lakes, especially made to attract tourists e. Lake
Gardens, Kuala Lumpur, Taiping Lakes Mans
mining activities, eg. tin mining in West Malaysia,
have created numerous lakes. Inland fish culture has
neoesitated the creation of many fishing-akes
Lake and Man
X careful examination of the lakes of the world Will

ther immense human significance, In countries
re they are found in abundance, such as Finland,
‘Canada, USA, Sweden and the East African states,
Takes together with other inland waterways, have
played a dominant role in the human, economic,
foci and cultural lie of the people. The pattern
of settlement, commerce and communication i very
Closely elated to the distribution ofthe water features

The following are the major uses of lakes and their
associated human activities
1. Means of communication. Large lakes like the
Great Lakes of North America provide a cheap and
comenien form of transport for heavy and bulky
foods such as coal, iron, machinery grains and
timber. The Great LakesSt. Lawrence waterways
penetrate more than 1,700 miles into the interior
They are thus used asthe chief arteries of commerce
Te is estimated that the annual tonnage passing
through the SaultSte Marie Canal, or the Soo Canal,
‘between Lake Huron and Lake Superior is greater
than the combined annual tonnage of the Suez and
Panama Canals.

2. Economie and industrial development, Early stile
ments and town sites were very much influenced by
the presence of lakes. Lakes are an cren more
cise factor when they are drained by large
fivers with outlets 10 the sea. The Great LakesSt
Lawrence waterways were responsible forthe develop
ment of the interior wheat farms and lakeside
Industries Raw materials, minerals and fuels ia |

conomically handled and assembled in the HOMES!
Sie Lakes Huron, Ontario, Michigan, Erie and
1), which has since become one ofthe greatest
dal districts of the world. Similar, Lakes

ind
Poyang, Tung Ting and other lakes of the central

4

‘Some ofthe aks of Finland scoured out y ice action
Camera Pros
Yang-tze basin have greatly assisted in the commercial
and industrial development of Wuhan (Wichang,
Hanyang and Hankow).
3. Water storage. Lakes of either natural or ar-
tificial origin are vital sources of domestic water
supply to surrounding towns and industrial cities.
‘For example in Britain Lake Thirimere supplies water
1 Manchester, Loch Katrine to Glasgow, Lake
my (in Wale) 10 Liverpool. The Okhla
“Reservoir supplies Delhi and the Vetaa, Var and
supply Bombay.
ele power genron. In mountainous
“kes or manmade reservoirs are uscd 10
"head of water 10 generate Mr.
Natural lakes are preferred to arti-

Gare vey ae thoughout the
the Niagara River flowing from
ke Ontario has a ey regula sor

‘water during the dry seasor
forced to close down during

Jakes will eventually be eliminated. and when they
‘ry up, their former beds are covered with thick
layers of fertile alluvium. They make excell
fgacultural land fk the fertile Vale of Pickering
in Yorkshire, or the rich Red River Valley of Canada
Which wasin ct the former site of Lake Agassiz

"Modern mulli-purpose dams, besides generating
Indro-elecric power also supply water for irrigation
‘eg. the Sennar Dam on the Blue Nile in Sudan, the

Burinjuck Dam on the Murrumbidgee in Australi,
and the Hirakud Dam (Madhya Pradesh) on the
Mahanadiin India,

6. Regulating river flows. A river with lange lakes in
iis basin seldom experiences serious floods or lack
fof water, By absorbing the excess water during
heavy rain, a lake reduces the effects of serious
flooding downstream. In the dry season, it releases
iiswaterso that steady low ofthe iver is maintained
Because lakes retain part of the sediment load,
rivers leaving lakes have clearer water. Lakes that
have such functions include the Poyang and Tung Ting
‘on the Yang-ize Kiang, Tonle Sap on a tributary of
tte Mekong, and Lake Constance on the upper Rhine
Where such lakes are not available, and flooding
serious problem, artificial reservoirs are constructed
‘eg. the Hoover Dam on the River Colorado and the
Bhakra and Nangal Dams on the Sue in India

7. Moderation of imate. Large and deep lakes
Which are heated more slowly than the land by day
and cooled more slowly than the land by night,
exercise) an appreciable effect in. moderating the
climate of a region in the same way as oceans affect
adjoining land masses. Water in the lakes cools the
‘air in summer by absorbing part of the heat and warms
it in winter by releasing the heat, For example the
faster shores of Lakes Erie, Ontario and Huron
Have a much milder winter than those of the west
because the on-coming breezes are warmed and early
frosts are minimised. This part of the Lake Peninsula
is therefore important for grapes and fruit farming.
Large lakes like Lake Michigan and the Caspian Sea.
also exert a slight influence on the cloudiness and
precipitation of the region, Their lange expanse of
Water acts almost like part of Ihe ocean, and helps 10
precipitate atmospheric. moisture into rain. The
Jeeward side of Lake Michigan records a litle more
precipitation than the windward side, though the
actual amount is often not easily noticeable. Small
lakes have practically no effect at all on either
temperature or rainfall

8. Source of food. Many large lakes have important
Supplies of protein food in the form of freshwater

fish, Sturgeon is commercially caught in the Caspi
Sea, Salmon and sea tout in the Great Lakes and
in Tonle Sap in Cambodia, fishing is a lading
occupation. Amateur fishermen have found fishin
in lakes and rivers a most rewarding pastime. I
‘many countries, artical lakes have been created for
land fish breeding. This is particularly important
in China and Jap
9. Source of minerals. Salt likes provide valuabl
rock salts Inthe Dead Sea, the highly saline wat
is being evaporated and produces common sal
almost indispensable for human well-being. Borax
ismined in the alt lakes ofthe Mojave Desert
‘Gypsum is mined in Cheshire, and Stassfurt, a
small distance from Berlin, isso rich in potash and
other chemical deposits, that they have given rise
to wide range of chemical industres In both these

air goologi

10. Tourist
the world’s best frequented. holiday
resorts are located on lakesdes for example, Lake
Geneva, Lake Lucerne, Lake Lugano, Lake Como,
Lake Placid (New York), Lake Vaner and Lake
Vatter, (Sweden), the English Lake District and
Taiping Lakes. The glacierformed lakes of the
Alps have made the 1
occupation of the Swiss

QUESTIONS AND EXERCISES

three of the following lakes
Great Salt Lake, Lake Toba
ke Victoria, Lake Seutari,

1. Locate an
Lake Tanganyik
Lake Como,
Lake Mead
(a) With the aid of sketch maps, explain
their mode of Formation
(6) State their specific value to the countries
they serve
(9 Name another lake outside that country
wich has Fury similar origins

() Kete lake

Y. deposiion

(8) Quote three actual examples ofeach

(e). State thee uses of man-made lakes
4. Rivers may be dammed for

) generating hydroclectriity

(b) controlling Hoods

(©) imigatingerops

(a) supplying drinking water
(e) assisting inland water anspor
For any four of them, locate a dam and a
river in which the damming has taken place
Explain b
has been successfully achieved,

how each ofthe above purposes

5. ach of the following terms arein one way or
another connected with lake formation and uses
For any fie of them give a concis explanation
of theiimplications and give a good example of
ach,

(a) basin of inland drat

() tectonic lakes

(© balls

(4) beaver dams

© playas

(D. barrier takes

(9) tms

10 Coastal Landforms

Action of Waves, Tides and Currents

coasting, under the constant action of, Ihe
ines tide and currents, is undergoing changes from

On dis wn in sie.
“do litle damage to the shoreline and may in-
hep to bil up baches and other depositional
entres ts in torts tha the ravages of the wanes

their greatest magnitude The average pressure
SE Atami wes un dasa costs aout 620 a
Sata he summer and treble than winter

storms, the pressure exerted is more than

Hh or 3 tons per square foot! Movements of
such intensity will wear dawn not only the li but
also sea walls and buildings. Tides and curents on
“contact withthe shores, make very ile direct attack
‘on the coastline, Tides affect marine erosion
“by extending a fine of erosion into a zone of erosion,
‘This zone corresponds to the area between the low
water Keel and the high water level, Currents help
40 move croded debris and deposit it as sit, sand
and grave along the coasts

he Mechanism of Marine Erosion
The most powerful agents of marine erosion are
Tikes Tir origin is due tothe sweeping of winds
tenace which seta series of undulating
ore caning forward. These become higher and
Dee A normal wave in an open ocean. may
Mae 20 fc high (the vertical heit between the
Bere and the troush) and 400 feet long (the vane
tena or the horizontal distance between one cres
find another), During storms this greatly increased
"spending on the speed and duration of the winds
Qeapproashing shallow water near the shoes, he
RI reused and the wives are cured or
cid agains the alignment of the coast Shallow
vater, when i es than the height of the waves,
heck their forward movement, the crests curl over
find break into the shores in à mass of foam as
Maker The water that finally rushes up the
Teach and hurs rock debris against he land is termed
Swish. The water is sucked back and retreats as
ca Another element in ofshore drift isthe
Undertow which lows near the bottom sway from the
Shore This current exerts a pulling effet which can
be dangerous to sea-bathers (Fig 7

Marine agents of erosion operate in the following
ays to transform the coastal landscape
1. Comsion. Waves armed with rock debris of all
sizes and shapes charge against the base of the ch,
and wear them back by corrasion, On-coming
unen and tides complete the work by swcepins
the ered material int the sea
2 Attrition. The constantly moving waves thst
transport beach materials such as boulders. pebbles
Shingle and fine sand also hurl these fragmen's
‘agaist one another, until they are broken downy
tion into very small pisces. The grinding and
Polishing of such fagmental materials against UN
faces and against cach other is larges responsible
forthe in sand which forms the beaches that re 8
typical ofthe seaside resorts
3. Hydraulic ation. In ther forward sure, 388
‘Splashing against the coast may enter joints
vies inthe rocks The air imprisoned inside ©
Hess ingre, When the wes u.
the compressed air expands with explosive violas
‘Such action repeted again and again soon colar
the cracks and rock fragments are prised apart
4 ‚action. On limestone coasts, the solve?!

‘ea water on calcium carbonate sts 10

changes in th rocks and disintegration 1

place. This process is limited to limestone coasts.

The rate of marine erosion depends on the nature
of the rocks, the amount of rock exposed to the
fea, the elects of tides and currents, and human
Interference in coast protection, Other effects such
fas vuleanicity, glaciation, earth movement and orga
ric accumulations have

Coastal Features of Erosion
‘Capes and bays. On exposed coasts, the continual
action of waves on rocks of varying resistance causes
the coastline to be eroded irregularly. This is
particularly pronounced where hard rocks, eg. gra
rites and limestones, occur in alternate bands with
clay, The softer rocks are

into inlets, coves or bays and the harder
(Fig. 74). Along the Dorset coast of souther
England, Swanage Bay and Durlston Head are
examples. Even where the coast is of one rock type
irregularities will be caused by variation within the

softer rocks e. sand at
worn b
ones persist as he

Fig: 74 Coastal features o diferetalercsion

rock, Thus Penang Island, made of granite, has many
‘bays and headlands Very large indentations such as
the Persian Gulf or the Bay of Bengal are due 10
other causes such as submergence or earth movement.
2. Clif and wave-cut platforms. Generally. any
‘ery steep rock face adjoining the coast forms a cit
‘The rate of recession Will depend on its geological
structure, that i the stratification and jointing of the
rocks and their resistance to wave attack. If the
beds dip seawards, large blocks of rock will be
slislodged and fall into the sea The cif wil sein a
Series of steps as shown in Fig, 75. On the contrary,
the beds dip landwards as illustrated in Fig. 76,
‘the cli will be more resistant 10 wave erosion, Some

Fig. 75 Cl beds dipping seawards

Fig. 76 Cif beds dipping landwards

of the best known cliffs are the chalk cliffs of the
English Channel and include Beachy Head which is
500 feet high, the Seven Sisters near the mouth of the
Cuckmere and the White CIS of Dover.

A the base of the eli the sea cuts a notch, which
gradually undermines the cliff so that it collapses

Fig. 77 The development of shore profile

at till

PAS a cil reoodes landward under the pounding of
‘aves an eroded base is et behind called war
platform. The platform, the upper part of which is
‘exposed at low ide, slopes gently semis and its
‘Surface i strewn with rock debris from the receding
Gif. Further abrason continues until the pebbles
are swept away into the sea. The eroded materials
fae deposited on the offshore trace (Fig. 7)
‘When the platform attains a greater width (eg. 30
miles in the ease ofthe wane-<ut platform of Sian
Mat off Western Norway), i is entire covered with
water and further erosion ofthe cls à neligible

3. Gave, arch, stack and stump. Prolonged vane
‘attack on th base of a cif excavates hole in regions
‘of local weakness called eves eg. at Flamborough
Head, England. When two caes approach one
another fom either ide of a headland and unie they
forman arch, eg the Neddie Eyencar Wick, Scotland.
Further erosion by waves will ultimately lead 10
‘the total collapse of the arch. The seaward por
‘ofthe headland will remain as apilar of rock known
as a sack. One of the finest examples of a stack is
the Old Man of Hoy in the Orkneys whichis of Old
‘Red Sandstone and is 450 feet high. Equally out-

A wave-cut platform on the Hong Kong coast ST Fok

78 Arch, stacks and stumps. Where two
F8 70 ve eroded on either side of à headland they
may eventually join to form a natural arch
he top of the arch collapses. stacks are
formed. These are gradusly worn down unt

they become stumps exposed only at low tide

standing are the Needles, Isle of Wight, which are a
group of stacks cut in chalk and diminishing in size
Seawards In the course of time, these

‘tacks will gradually be removed. The ve
pillars are eroded, leaving behind only 1
‘which are only just visible above the s
those of the St. Kia:

Scotland (Fig 78)

4 Geos and gloups. T
waves against the roof of a cave may enl

e occasional splashin

bints when ci
oi

natural sb
pierce 1
the cave may force w
this hole. Sue

noise made byt
(ig. 9). An ex

supe ino
RE
io trough whch ai

Fig. 79 Gloup ‘water are tree,

ness Scotland. The enlargement of blow-holes and
the continued action of waves weakens th

When the roof collapses a long, narrow in

develops Such deep clefts, whi

deep and equally long, are called geos eg. the Wife
Geo, near Duncansby Head, Scotland (Fi. 8

Fi. 80 Geo
Coastal Features of Deposition

1. Beaches, Sands and gravels loosened from the
land are moved by waves to be deposited along the
shore as beaches This is the most dominant form
of the constructive work of the sea. The croded
‘material is transported along the shore in several
distinct ways The longshore dr which comes

es the material along the
shore in the direction ofthe dominant wind (Fig, 81).
At the same time, the be removes part of the
‘material seawards along the bed of the sea, and
deposit it on the off-shore terrace and even beyond.
Finer materials such as silt and mud are deposited
in the shallow, waters of a sheltered cous.

The constant action of the waves automatically
sorts out the shoreline deposits in a graded manner.
‘The coarser materials (cobbles and boulders) are
dropped by the waves at the top of the beach. The
finer materials (pebbles and sand grains) which are
carried down the beach by the backwash are dropped
loser to the sea. On smooth lowlands, beaches may
continue for miles, like those of the east coast of
West Malaysia, bt in upland regions where the land
descends abruptly into the sea, such as the Chilean
coast long beaches are absent
2. Spits and bars. The debris croded by waves is
‘continually moved by longshore drift and where
there is an indentation in the coast, such as =|

mouth of a river or a bay, material may continue
19 be deposited across the inlet, As more materials

25
u

Fig. 62 Development of pit

“are added, they will pileup into ridge or embank-
‘ment of shingle forming a tongue or sl. with one
End attached to the land andthe other end projecting
“into the sca (Fig 82), eg. Cast Spit, Southampton
‘Water, England or those slong the coast of Kelantan.
‘Oblique waves may curve the spit into a hook or re-
‘curved spit, When the ridge of shingle is formed

‘euch coasts as ría coasts fiord coasts, estuarine coasts
‘ad Dalmatian of longitudinal coasts.

Fe Coastlines of emergence. These are due to the
pun ofthe and ora fal inthe sea level. They are
e common and are represented by the uplited
fowland coast and the emergent upland
Coastlines of Submergence

{Bia coasts. During the Ice Age
rater vas Tocked up in ice The warmer climate thay
Fotlowed melted much of the ice, Subsequent
there was an inerease in the waters of the o

fand the sca level rose appreciably. In some cases
Avis estimated that there vas rise of almost 300 fc!

OO)
OD

Fig. 85 À ri cost (discordan, Antic typo)
In uplod costal regions where he mountains run at
righ angles tothe sea, transverse or discon
to the coast (Fig. 83), à rise in the sea level sue
or dromns the lower parts ofthe valleys to form lone
arrow branching inlets separated by narrow head:
lands They diter from fords in two. important
respets ie they are not glaciated, and their depth
increase awards Aria. cous is typical of the
Allan typeof coast ike those of northwest Francs
‘nonth-west Spain, southnext Ireland, Devon and
Cornwall, As ras are generally backed by highland:
they support few large commercial ports though the?
“have deep water and offer sheltered anchorage. The)
Tune been extensively used for siting fishing por

| bases such as Plymouth and Brest.

2. Fiord coasts. Fiords are
acia troughs. T

plunged down from the bi
all often rising sra
branches joining the n
to the greater intensity o
for great distances inland but
atthe seaward end formed b
called the threshold (Fig. 8

‘OM the ford coast are

asc 6 Daman coast

Fig. 84 A ford coast (submergent and glaciated)

nerous islands or skeries which, with the shallow
thresholds, sometimes only 200 fet deep. complicate
coastal navigation, Fiord coasts are almost entirely
fonfined to the higher latitudes of the temperate
regions which were once glaciated eg. Norway
‘Alaska, British Columbia, southern Chile and the
South Island of New Zealand. Some of the large
Finds are extremely long and deep. For example the
Sogne Fiord of Norway is 110 miles long, 4 mies wide
and almost 4,000 feet deep in its mid-chamel
Despite their deep and sheltered water, few large
ports are located in fiords. Their mountainous
background with poor aessiblity inland attract few
seitlemenis. Agriculture is confined to the deltaic
Tans, built up where streams fow down to the fords
“The few towns that exist either as fisting or market
‘centres eg, Trondheim, are only of loca importance

3. Dalmatian coast. This is the longitudinal coast
Where mountains run parallel or concordant 10 the
‘coast, The name is taken from the cous of Dalmata,
Yugoslavia, along the Adriatic Sea, where the submer
‘ence of the coastline produces long, narow inlets
‘with a chain of islands parallel to the coast, The

Fig. 85 A Dalmatian const concordant, Pacific type)

clongated islands are the crests of former ranges
And the narrow sounds were the former longitudinal
valles (Fig. 85). The Dalmatian type of coast is also
Typical of the Pacific coast where the ranges are
parallel to the coast eg. western coasts of Nor
And South America but there the coastline is more
regular Like the ria and ford coasts, the moun-
{ainous nature of the Dalmatian coastline hinders
communication inland. It has deep, sheltered ha
bours but no distinguished ports On the Pacific
coast, however, there are some important ports such
fs San Francisco

‘A Estuarine coasts. In submerged lowlands, the
‘mouths of rivers are drowned so that funnel-shaped
Stuaries are formed. If their entrances are not silted
by moving sand-banks they make excellent sites for
ports eg. the estuaries of the Thames, Elbe and
Plate are the sites of such great seaports as London,
Hamburg and Buenos Aires Tidal effects further
enhance the value of the ports and even when there
isa little siting, modern dredges help to Keep the
ports open all the time.

a
po
continental shelf produces a smooth, gently sloping
a

—

‘Where the emergent deposits from the continental
shelves are sandy and gravel, beaches and marine
Gunes are formed. Ports that were once located on
the former coast become inland towns Examples
Of uplifted lowland coasts include the south-eastern
USA. western Finland, eastern Sweden and parts of
‘coastal Argentina south ofthe Rio de la Plata

2. Emergent upland coast, Faulting and earth move-
ay thet up esta lts so that he noe

i abe, wi consequent emergent feature,
ech the mont prominent The raed
here ofthe ws though it may

of weaknes or cared a wave eut
It has itl potential for good
{ unlnd coasts are

QUESTIONS AND EXERCISES

1, By reference to specific examples describe
Some of the major coastal features resultin
from the constructive and destructivo work
the sea

2, With the aid of annotated dia
Gibe the appearance and formation of any
three of the following pairs of features of coast
landforms

(a) lf and wave-ct platform

(6) geo and blowhole

(@) arch and stack

(8) spitsand bars

3. How can shorelines be classified? Describe
any one method of classification and explain
briefly some of the major shoreline features
that you have classified.

4, With the help of diagrams, explain 1
“istinet differences between the following coast
lines of submergence

(a) fia coast

(0) ford coast

(©) Dalmatian coast

(@) estuarine coast

5. Choose any tree of the following terms con
nested with marine landscape. Explain the
medningof eachand stateitsrolein transforming
Ale cousine,

(a) longshore drift

(®) undertow

(©) concordant coast

(A) raised beach

(©) tomboto

Chapter 11 Islands and Coral Reefs

An island isa piece of land surrounded on all sides
by water. I ma

in open oceans or seas. Smaller ones of only local
signifi

Generally speak

the following 1
1. Continental lands, These islands were formerly
part of the mainland and are now detached from th
continent. They may be separated by a shallow
lagoon or a deep channel. Their separation could x
due to subsidence of some part of the land or to a
rise in sea level so that the lowland links are sub-

merged by the sea. Thi
the neighbouring mainland can be tr
Similar physical structure, flora and
on both side

modification by

he channel. In the course of time,

en and other nat
gie rise to diferent surface Features. But even then,
the basic structural features will remain the same
Continental stands may appear

(@) Individual islands. These le just outside the
continent, very much associated with the charac
teristic features of the mainland of which they were
once part. Some of the oulstanding examples are
Newfoundland, separated from the mainland by the
Strait of Belle Isley Madagascar, by the Mozambique
Channel; Ceylon by the Pak Strait; Tasmania by the
Bass Strait and Formosa by the Formosa Strat

(0) Archipelagoes or ¡land groups. These com:
prise groups of islands of varying sizes and shapes,
eg. the British Isles, the Balearic Islands of the
Mediterranean and also those of the Aegean Sea.

(©. Festoons or island ares. The islands form an
archipelago in the shape of a loop around the ede
or the mainland, marking the continuation of
mountain ranges which ean be traced on the continent,
eg. the East Indies, the Aleutian Islands, Ryukyu
Islands, Kurile Islands and other island ares of the
Pacific coasts
2. Oceanic islands, These islands are normally small
and are located in the midst of oceans. They have
‘no connection with the mainland which may be
hundreds or thousands of miles away. They have
flora and fauna unrelated to those ofthe continents.
‘The Galapagos Islands have many unique species
Of animals, Due to their remoteness from the major
trading centres of the world, most of the oceanie

lands are very sparsely populated. Some of them
provide useful stops for aeroplanes and ocean

Rarotonge inthe Cook Islands, a rugged volcani island
Inthe Pacific NZ. High Commission Malaysia

steamers that ply between continents across vast
Stretches of water. Generally. speaking, oceanic
islands fll into one of the following groups
(a), Volcanic islands, Many of the islands in the
oceans are in fact the topmost parts of the eones of
volcanoes tht rise from the ocean bed. Most of them
are extinet, but there are also some active ones. The
best known volcanic peak of the Pacific Ocean is
Mauna Loa in Hawai, which is 13,680 feet above
sea level, Tracing downwards, Mauna Loa is
found to have been built up from the ocean floor
ata depth 18,000 feet below the water surface! Other
volcanic islands have emerged from the submarine
igs ofthe oceans
“The volcanic islands are scattered in most of the
scans In the Pacific Osean, they occur
»

‘tiny cup of coral and helps 10 fo

in several groups such as the Galapagos
ne and the South Sea islands In the Atlantic
tie the Azores, Ascension, St. Helena, Madeira and
the Canary Islands Those of the Indian O

Are Mauritius and Reunion. In the Antrct
re the South Sandwich Islands, Bouvet Island
and many others

(®) Coral dans Unlike the volanie islands
A2 coral islands are very much lower and emerge
fest abone the water surface These island, bul
AP by coral animal of various species, are found
ah eur the shores of the mainland and inthe mid
‘of oscans Coral islands include the Marshal Islands
Gilbert and Ellie Islands of the Pacific; Bermuda
{nthe Atlantic and the Laccadives and Maldives of
the Indian Ocean.

Coral Reefs

In topical seas many kinds of coral animals and
marine organisms such as coral polyps, calcareous
algae, shellforming ereatures and_fime-secreting
plants live in large colonies. Though they are very
Tiny creature, their ability to secrete calcium car
Bonate within their tiny cells has given rise to a
peculiar type of marine landform. They exist in
‘umerous species of many forms, colours and shapes.
Under favourable conditions, they grow in great
profision just below the water level. Taking coral
Animals as a whol the polyps are the most abundant
“and also the most important. Each polyp resides in

tatu atoll inthe Tokelau sland group MZ High Commission Malaysia

their limy skeletons are cemented

When they di

Mine Imestone. There are also non-reet
folding species such as the ‘precious corals’ of the
Half Dekan and the red coral of the Mediterranean
"ieh may survive inthe colder and even the deeper

vee Asa rule they thrive well only in thew
tropical seas.
Me rectbuilding corals survive best under the

following conditions

1. The must not fall

ESE (UC). This viral limits the arcal dis
tribution of corals to the

ss Again they will ot here are
Beir ewrents because of the upwelling of the col
ater from the depths that cools the warm surface
Water This explains why coral reefs are generally
sent on the western coasts of continents. On the
ther hand the warming effet of the

fe the Gulf Stream, means that corals are found
far to the north of the West Indies in the Adantic

Ocean. The Pacii and the Indi
ave the most numerous coral refs

2. The d should not exceed 30
fathoms or 180 feet, because beyond this depth
sunlight is too faint for photosynthesis to take

place This is essential for the survival of the
Fhicroscopic alga, on which the coral polyps depend.
Shallow water of less than 100 feet is ideal, But
there should always be plenty of water as polyps
cannot survive fortoo long out of water

Types of Coral Reefs

‘There are three main types of coral ret.

1. Fringing reefs. Af 4 is a coraline
plaform

From the mainland. It is sometimes separated fi
the shore by a shallow lagoon. I is widest when
Tinging a protruding headland but completely absent
‘when facing the mouth of a stream. The outer ede
rows rapidly because of the splashing wanes at
‘continuously renew the supply of fresh food. The
reefs may ing just above the

out a mile wid, Ii

Fa. 88 Fringing root

level of low water and sloping steeply dommwa
fon the seaward side 10 a depth of about 100 fet
(ie. 88).

2. Barrier refs A barrer rs is separated from the
‘roast by a much wider and deeper channel or lagoon
(Fig 89), The reef is partially submerged. Where
i cs above the water lvl and sand can secumulate
‘om ita tle vegetation is possible, The barrie reels
have arrow gaps at several places 1 allow the water
from the enlosed lagoon to retu tothe open scan.
‘Such gaps are very useful for shipping and provide
the only entranss for ships to enter or leave the
lagoon. The best known Darier reel is the Great
Baier Reef off the cost of Queensland, Australia.
Its 1200 miles long, separated from the enast by a
‘hanna 100 miles wide in places and over 200 fet

een

SE" toi. Atos are similar to barrie reefs except
that they are in shape enclosing a shallow
lagoon without any land in the centre. The end
Ye ing is usualy broken in a ew places 1 allow
fhe ree Row of water (Fig. 90). On the inside of
the rc sand and limestone debris collect and palm
Yes Ike coconuts may grow. Such palm tees

st

thrive well in the brackish water of the lagoon. The
puts fall into the water and are distributed widely
ty foating from one coral island to another. The
alm waters are useful for Sshing and canocing
Some ofthe large atolls e. Suvadiva inthe Maldives
west of Ceylon, have a lagoon over 40 miles across
‘A number of them provide essential air bases for

(0 A fringing reet

lagoon :

W upwards at the rate of a foot ina decade
10 keep pace with the rising water level (Fig 918).
Coral refs, where islands still project abone seh

med. Recent evidence
ange in sea level and con
inde. However the deepest

trans-Pacitic aircraft. reveal basaltic rocks. These correspond
10 the subsided islands envisaged by Darwin, Thus a
combination of the two theories accounts for all he

important features of coral reefs and atoll

La 4

{| Subsidence of the land leads toa barrier eet
veloping.

The Probable Origin of Coral Reefs

“The subject of the origin of coral refs has been
audi and debuted for over one and half centuries
Several theories have been suggested but none à
nivel accepted

The most widely accepted theory is that put
forward by the great scientist Charts Darwin,
alter his voyage to the Pacific islands in 1842.1 is
known as the subsidence theory. Darwin assumed
that al coral reefs began as fringing res around
anisland or the topmost portions of extinct volcanoes
that stood above the ocean bed. Due to a
dosmwarping of the
aly subsided, The corals continued to grow upuardı
to keep pue withthe subsidence. The growth was
more vigorous tthe outward edge than
âge because ofthe more favourable living conditions.
for corals o the encircling reef widened. Tt then
formed a barrier rec, wit lagoon between the island
and the rs. Eventually, when the land completely
Submerged, only the outer rims of the reefs were
seen, forming an atoll. The submerged island was
‘covered by a layer of sediment so thatthe character
isic circular lagoon is generally shallow. Thus
atols mark the position of the former islands (Fi
la), More recent researches by oceanosraphers
Jue revealed that the ocean floor has, infact, been
subjected to subsidence especially in the Pac
Darwin's explanation was therefore generally correc.

Amongst the other theories, perhaps the American
groeraper, RA. Daly’ glacial control theory put
forward in 1910 is worth consideration, During
his vst to Mauna Kea in Hawai, he noticed. the

QUESTIONS AND EXERCISES

1. Give a concise classification of the islands
of the word, Quote actual examples of islands
to justify your proposed classification,

2. The following are some of the islands of
the word. State in which part of the globe
they are found. For any three of them account
for their probable origin,

Sakhalin Islnd

Andaman Islands
Fig. 91 (a) Darwin's theory of subsidence (coral reat Re

‘rowing upwards and outwards to Keep ee
passing from Hawaiian Islands

‘and eventually Cree

Fig. 89 Barirreet

(li) Further subsidence matched by the growth of
oral leads to an atoll

3. What are the three general types of coral
reef formed by coral animals Point out the
distinct differences betwen them.

4. Explain cents how coral ree ae formed.
Under what conditions do corals thrive best?

5. With the aid of examples and diagrams
explain any three of he following terms connec:
ted wit sands and coral reefs.

(a), continental islands

(0) archipelagoss

(©) occanic islands

(@) coral polyps

(©) fringing ets

© als

(W sland is planed when sea sat x evel

clos relationship between glaciation and the develop-
‘ment of coral reefs He believed that during the
height of the Ice Apes, the water was too cold for
any coral growth to take place. With the absence — ___.
‘of @ coral barrier, marine erosion was able to attack 2
‘and lower the islands. With the return of the warmer

(6. a evt ins and coal grows ud fomi

Fig. 91 (b) Daly's Glacial Control Theory
Bi

Chapter 12 The Oceans

Exploring the Oceans
The cœans comprising more th
140 milion square mies of the ©
cual wating. to be developed, of ocean foors and map the reli of the
Fe ele ue of ol té. mammals, Trained open equipped with modern bre
Pete sa dnd cer marin Module ides apparatus are employed

Fea ea ae poner Formal ccano- on {rom great deihs. Deep sea core samples
Soe cagon bern only wit the Pris obtained by boring for the study of the exc
Sa eer ee ar 08731870), the fist Seposts— te arios Kind of cor, msn cas
ESS world-wide depre expedition. tttomatioreconting thermometers and other

o he ale of the ocans has Ev instruments can bolowered to any require depth

eee stan jota rent years by stationary vessels with laboratory fais o
Ferret te Bet sexo have been conduc processing any required data, For the observation
GEG cae ion univers, government and measurement of current Now

nee td other inemaional organizations. current meters using propellers, vanes or penduluns
Fae toes mous tteraional oxanographc re: have been designed Sealed bottles and other Host
sre seen the International Counell for the ing objects containing instructions for reporting
ocn of the Sex wih lis headquarters in their precise time and place of discovery are released
Chen Ocean exploration for the observation in large numbers to compu the rate and direction
Tel tending of omanogrphie data & a very ol dut and current ow. With all these modern
pease mater It ines the opertin and techniques atthe disposal of the oceanoerphers
(nee of special) equipped veses in mid- our knowledge of the mysteries of the occans 1
Nee for log periods and larpescale verano: — grey increased, But there is sill much 10 be
ophic rescarehs are this best underaken by discovered
a ‘bodies: The older echo-sounding tech-

len eves 10 Find the preci

arious kinds of

Piston cover, such as tis, aro used to sample the
Sediment on the ocean lors Mohammad Ayo

The Relief of the Ocean

where the coasts are extrem
the Rocky M
‘ental shell may be entirely absent, OM broad low
and coasts like those of Arctic Siberia, a maximum
‘width of 750 miles has been A width of
20 to 100 miles is à intered, The angle
Of the slope is also
here the ©
of Lin 500 is common
Many regard the continental shelf as part of the
a the close
perte lait
Several hundred feet
Shelves could have been caused by wave erosion
‘where the land is being eroded by the sea as shown in
Fig. 93. Conversely such shelves might have been
formed by the deposition of land-derived or river

arible, and is nor
i widest. À

10 arise in sea level, eg
ge, when the ice in the em
es melted and raised the seu level by

‘continental edge

port on the tide Most of the worlds greatest
Scapots including Southampton, London, Hamburg
Rotterdam, Hong Kong and Sin

2. The continental slope. At the eûie of the

continental shel

slope

3, The deep-sea plain,

tworthids of the ocean floor, generally termed

abysal plain. E was once thought 10 be featureless,
bys

This isthe undulating plain
ree miles below sea lve

but modern sounding devices reveal thatthe
plain i far from being level. 1 has extensive subma
ine plateaus, ridges, trenches, basins, and oosanic
ands that rise above sea level in the midst of
‘oceans e. the Azores, Ascension Island

4. The ocean deeps, These are the long, narrow

plankton

‘continental shalt
contnontal slope

aut
“marine tidge

Fig. 92 Tho rele! of the ocean basin (a typical
section} with ocoaniedeposits—mud lay

fd oozes,

s

"rss tat plunge as great san des 0 a depth
‘OF 5000 fathoms or 20000 fet! Contrary o our
e Tost ele desp trenches aro not
e in mida of ocean. Tey are more often
ound dose 10 the continents particularly in the
Paci Osun, her several exp trenches have Deen
une, The rate known ocean dep is the
ana Tech nar Guam Island, whch is more
M000 Tec deep. We can see from this that
"exam tenhes ae greater in magnitale than the
mountains on and, forthe highest peak

weet on 29,08 fet, Or notable ocean

the Mindanao Deep (35.000 fet), the

ya Tench (31.00 fet) andthe Japanese Trench
00 fe) alin the Pac Ocean,

Fig, 94 Coninomal shell formed by processes of
‘deposition

3. The clays, These occur mainly as red clays inthe
“per parts of the ocean basins, and are particulary
abundant in the Pacific Ocean. Red clay is believed
16 be an accumulation of voleanie dust blown out
From voleanoes during volcan eruptions

Salinity of the Ocean
‘Almost every known chemical element can be
found in varying proportions in the oceans whose
‘most characteristic feature str salinity in contrast
10 the fresh water of lakes and streams. All sea
‘water contains large amounts of dissolved mineral
mater of which sodium chloride or common sat
Alone constitutes more than 77 per cent, The other
more important compounds include magnesia,
«akiumand potassium, while the rest ae distinguish
fable only in trices of very minute quantities. Due
to the free movement of ocean water the proportions
of diferent salis, remain remarkably constant in all
"scans and even 10 great depths, But the degree
‘of concentration of the sat solution in oceans does
‘ary appreciably in diferent areas. This is expressed
assalnity, the degree of saines of water, ether as
percentage or more often in parts per thousand
Nariations ae shown in salinity distribution maps
by lohan. lines joining places having an caval
“degree of salinity.
Generally speaking, the average salinity of the
oceans is 35.2% about 35 parts of sal in 1,000 pats
water In the Baltic Sea, where there is much
ion by fesh water and melting ic, the salinity 6
Oe ‘only about 7 % In the Red Sea where
and fever ren

salinity is perhaps, that of Lake Van, in Asia Minor

with 330 9. I ia sll lake, and salts are collected
from its shores. The density of the water is so high
that in Lake Van or the Deud Sea ii almost impos

Beginner-swimmers wil find it much
ser to float ere than anywhere else! The variation
‘of salinity inthe various seas and oceans is affected by
the following factor
1. The tate of eraporation. The waters fringing the
High Pressure Hells of the Trade Wind Deserts
between 20° and 30°N, and S,, have high salinity
because of the high rate of evaporation caused by
high temperature and low humidity. The temperate
‘oceans have lower salinity due tothe lower tempera
ture and a lower rate of evaporation
2. The amount of fresh water added by precipitation
Salinity is lower than th
al waters because of the
heavy daily rainfall and high relative humidity,
Oceans into which huge rivers lke the Amazon,
Congo, Ganges, Iravaddy and Mekong drain, have
much of their saltness diluted and have a lower
salinity. The Baltic, Arctic and Antarctic waters
ive salinity of les than 32% because of the older
climate with litle evaporation and because much
fresh water is added from the meling of icebergs. as
well as by several lago poleward-bound rivers eg.
(Ob, Lena, Yensey, and Mackenzie.
3. The degree of water mixing by currents. In
‘wholly or partially enclosed seas such asthe Caspian
Sea, Mediterranean Sea, Red Sea and Persian Gulf,
the waters do not mix frecy with the ocean water
“and they are not penetrated by ocean currents
Salinity is high, often over 37 %o. In areas of inland
drainage without links with the oceans, continuous
‘evaporation under an almost cloudless sky causes the
accumulation of salis around the shoes In the open
‘oceans where eurent feey flow, salinity tends to be
near the average 35 % or even a lil lower, The
range of salinity is negligible where there is free
‘mixing of water by surface and sub-surfae current

‘The Temperature of Ocean Water
Like land masses, ocean water varies in Lempe-
ature from place to place both atthe surface and at
“reat depths Since water warms up and cools down
‘much more slowly than the land, the annual ne
‘of temperature in any part ofthe ocean is very much
smaller. I i less than LE, for most of the open,

‘Generally, the mean annual temperature of
the surface ocean water decreas from about 70°
in equatorial areas to SS’ at latitudes 48°N. and Sa

and drops almost to freezing-point at the poles The
reduction of temperature with latitude is however
never constant, because of the interference by warms

the

and cold currents winds and air masses. U
solid earth, ocean water is mobile and variation
temperature between different parts of the oceans
an be expected, Water Bowing out from the Arct
“and Antarei as cold currents, such asthe Labrador
Current off northeast Canada, tends 10 reduce the
surface water temperature. Ports of eastern Canada
ven at 45°N, are thus ccbound for almost half the
year, In the same way, coasts warmed by warm
Current, such as the North Atlantic Drift, have their
Surface temperature raised. The Norwegian coast
‘ven at latitudes 60° 10 70°N. is ke-free throughout
the year!

The highest water temperatures are found. in
‘enclosed seas in the tropics eg. the Red Sea which
records a temperature of 85° to 100°R. The Arctic
and Antarctic waters are so cold that their surface
is permanently frozen as pack-ice down to a depth
‘of several feet, In the warmer summer, parts of the
Joe break off as icebergs that both dilute the water
and lower the surface temperature of surrounding
door seas

The temperature of the oceans also varies ver
cally with increasing. depth, It decreases. rapidly
for the fist 200 fathoms, at the rate of 1°F for every
10 fathoms, and then more slowly until a depth of
500 fathoms is reached, Beyond this, the drop is
searely noticeable, less than IF. for every 100
fathoms. In the ocean deeps below 2,000 fathoms
(12,000 fet, the wate is uniformly cold just ile
above frezing.point. It is interesting 10 note that
even in the deepest ocean trenches, more than 6 miles
below the surface, the Water never freezes Tt is
estimated that over 80 per cent of all ocean waters
have temperature between 35" and 40°F.

‘The Movements of Ocean Currents
(Osean currents are large mass of surface water
that eiculate in rula pateras around the oceans
as shown in the world map in Fig. 95. Those that
‘how fom equatorial regions polewards have a higher
surface temperature and are Warm curren Those
hat ow rom polar regions equatorwards have à
Tower surface temperature and are cold coment.
Their diction of movement is indicated by the
roux But why should they follow such a patern?
Some ofthe undying factors ae explained Below.
1. The planetary minds, Between the equator and
the tropics blow the Trade Winds which move

‘equatorial waters polewards and westwards and
‘warm the eastern coasts of continents For example
‘the North-East Trade Winds move the North Equa
{oral Current and its derivatives. the Florida Current
‘and the Gulf Stream Drift to warm the southern and
faster coasts of USA. Similarly, the South-East
‘Trade Winds drive the South Equatorial Current
‘which warms the easter coast of Brazil as the warm
Brazilian Current.

Tn the temperate latitudes blow the Wester.
‘Though they are less reliable than the Trade Winds
they result in a northeasterly flow of water in the
‘northern hemisphere, so that the warm Gulf Stream
is driven to the western coast of Europe as the
‘North Adantic Dai. In a similar manner, the
Wisteria th southern hemisphere, drive the West
Wind Daft equatorsards as the Peruvian Current

"South America and the Benguela Current off

puthern Africa, The planetary winds are probably
dominant inluene on the fw of ocean currents.
evidence of prevaling winds on current

is seen in the North Indian Ocean. Here the
‘ofthe currents changes completely withthe

‘of the monsoon winds which come from the

“Temperatures. There is much difference in the

nperatur of ein waters at he equator and atthe

je As warm water is lighter and rises and

is denser and sinks, warm equstoral

‘lowly along the surface polewards,

cold water ofthe polar regions creep
the bottom of these equatorwards

5. Land. A land mass always obstructs and diverts
2 current. For instance, the tip of southern Chile
diverts part of the West Wind Drift northwards ay
the Peruvian Current. Similarly the “shoulder” of
Brazil at Cape Sao Roque, divides the west-lowing
‘equatorial currents into the Cayenne Current which
flows northwestwards and the Brazilian Cur
‘which flows south-westwards

The Circulation of the Atlantic Ocean
La us now study more closely the cirulation
of ocean curents in the Atlantic Ocean. We shal
begin with the North and South Equatorial Current
tie equator The steady Trade Winds constantly
dit evo steams of water from eas to west. AL he
Shoulder of norti-east Bri, the protruding land
mass splits the South Equatorial Current into the
‘Cayenne Current which fons long the Guiana cost,
and the Brazilian Current which flows southwards
long the east coast of Brazil
Ta the North Atlantic Osean, the Cayenne Current
is joined and reinforced by the North Equatoral
Curent and heads northwestward as a arge mass
of eaustoria water into the Caribbean Sc. Part
ofthe current enters the Gulf of Mexico and emerges
{rom the Florida Stat between Florida and Cuba
a the Florida Curren. The rest of the equatorial
ter flows northwards east of the Antilles to join
the Gulf Stream off the south-astern USA. The
Gulf Seam Drift sone of the strongest ocean cur
rent, 35 o 100 miles wide, 2000 feet deep and with
4 velocity of three miles an hour. The eurent hugs
Abe coast of America as far as Cape Hatteras (latitude
3SN), where it is defected eastwards under the
combined influence of the étre and the rotation
ofthe earth, I reaches Europe asthe North Atlante
Drift. This cursen, Moving at 10 miles per day
‘aries the warm equatorial water for over thousand
niles to the coasts of Europe, From the North
Atlantic, it fans out in three directions, eastwards
to Britain, northwards to the Arctic and southwards
along th Iberian coat, sth col Canaries Current.
‘Oceanographic researches show that almost 1¥0-
thirds of the water brought by the Gulf Seam othe
“Artic regions is returned annually to the wopkal
latitudes by dens, old polar water that creps south
‘wards in the ocean depths. The Canaries Current
‘ventully merges with the North
„ completing the clockwise circuit

area in the middle

Aime
Ocean

‘South Paciie Ocean,

i

Fu oe

Fig. 95 Oceans currents of the world

amount of floating seaweed gathers and the
eal the Sargasso Sos

Agar fromthe clockwise cretion of the
curren there are alo ares hat eier the North
‘Alani rom the Arto regions These cold waters
are Blown south bythe outoving polar winds
The Inminger Curent or East Grand Current
fos between land and Grealand and cool the
North Allan Dit atthe pont of eamerence
The cold Labrador Cument Gis soutvastards
Between West Grenland and Bali Land to mes
the warm Gulf Steam off Newfoundland, a far
south as SÓN, where the ch cid uth by
the Labrador Curent mel

“The South Atlante es flows the same pte
filon as the Noth Atane Osan. The
Amor dieses are that he cit anche
And the colon of saved in the sl wa of
‘hemidSouth Alanis notso diinie.

‘Where the South Equatorial Current is spit at
Cape Sao Rogue. one branch turs south as the
vam ‘Curent Ne deep Bue waters are
sy distinguishable fom “the vélos, muddy
‘ates carro hundreds of mies out Lo a bythe
Amazon futher north, At about 40. eine

e

of the prevailing Westerlis and the rotation of the
arth propel the current eastwards to merge with the
cold West Wind Drift as the South Atlantic Current,
(On resching the west coast of Africa the current is
diverted northwards as the cold Benguela Current
(the counterpart of the Canaries Current). It brings
the cold polar waters of the West Wind Drift into
tropical latitudes. Driven by the regular South-East
‘Trade Winds, the Benguela Current surges equstor-
wards in a north-westerly direction to join the South
Equatorial Current. This completes the circulation
‘of the currents in the South Atlantic. Between the
North and South Equatorial Currents is the east-
flowing Equatorial Counter Current,

‘The Circulation of the Pacific Ocean
‘The pattern of circulation in the Pacific is simi
to that of the Atlantic except in modifications which
can be expected from the greater size and the more
‘open nature of the Pacife. The circulation can be
«sil followed in Fig, 95. ey to correlate it with the
‘currents in the Atlantic.

‘The North Equatorial Current flows westwards
with a compenssting Equatorial Counter Current
running inthe opposite direcion. Due to the greater

expanse of the Pacific and the absence of an obstruct
ing land mass the volume of water i very much
“iter than that ofthe Ani equatorial current.
The North-East Trade Winds blow the North
‘Equatorial Current off the coasts of the Philippines
and Formosa nt the East China Sea ste Kuroshio
or Kuro Sivo or Japan Current. is warm waters
are carried polenard as the North Pace Dri,
iceping the ports of the Alaskan coast ire in
"winter The cold Bering Current or Alaskan Current
eps southwards from the narrow Bering Strait
and is joined by the Okhotsk Current 10 mec the
arm Japan Current a te Oyashio, off Hokkaido.
‘The old mater eventually sinks beneath the warmer
waters of the North Pace Dit. Part of it drifts
Castas as the cool Californian Current along
the costs ofthe western USA. and coles with
the North Equatorial Current to complete the cock
ie circulation.
“The currn system ol he South Pacis the same
stat ole South Antic. The South Equatorial
sent, den by the South-East Trade winds
‘ows southwards along the coast of Queensland
as the East Australian Current, bringing warm
lol waters into temperate waters The current
urns eastwards tonards New Zealand under the full
for of the Westeris in th Tasman Sea and merses
with part of the cold West Wind Dat asthe South
sie Current. Obstructed by the tip of southern
Chie, the current turns northwards along the western
‘of South America as the cold Humboldt or
‘Peruvian Current, The cold water chil any wind
at blows onshore so that the Chilean and Peruvian
couts are practical rules The region s rich in
‘mirosopic marine plants and animals that aut
“huge shoals of fish Consequently, millions of sea
nr
completely whiten the coastal cis and islands
orming thick deposits of guano, valuable source
of fertilizer. The Peruvian Current eventually links
up with the South Equatorial Current and completes:
‘the eee of eures inthe South Pacific,

reversal of the direction of currents between summer
And winter, due to the changes of monsoon winds
Ta summer from June to October, when the dominant
wind isthe South-West Monsoon, the currents are
blown from a southwesterly direction as the South
West Monsoon Drift. This is reversed in winter,
beginning from December, when the North-East
Monsoon blows the eurrents from the north-cast as
the North-East Monsoon Drift. The currents of the
North Indian Ocean, demonstrate most convincingly
the dominant effects of winds on the circulation of

QUESTIONS AND EXERCISI

1 With the aid of lage sketch maps, describe
and explain the circulation of currents in either
the Atlantic or the Pacific Ocean. Your map
should differentiate clearly the warm currents
From the cold currents

2.. Explain by reference 10 actual examples the
effects of ocean current on:

(a) climate

(6) navigation

(©, economic activites

3. What is meint by the relief of the oceans?
In what ways are the structure and composition
Of the reli different from those of the land
surface?

4. Give a reasoned explanation of any three
of the following.

(2) The richest fishing grounds are located
on continental shelves.

(0) The average salinity of the Baltic Sea
is only 7 Ya whereas that of the Dead Sea is
240%.

(©) The temperature of the ocean water
‘aries both horizontally and vertically

(4) The dominant influence on the cireu-
lation of ocean currents is wind

5. Write brief notes on any three of the follow
ing terms associated withthe oceans,

(a). deep sea core samples

(0) Mariana Trench

(©) isohalines

(@) Gulf Stream Drift

(©) Sargaso Sea

D QUESTIONS FROM CAMBRIDGE OVERSEAS SCHOOL CERTIFICATE

SELECT

1. Either (a) Ineach of two continents name. a volano,
fi, arif vale,
You need not select and from the same continent
(6) With the aid of diagrams, describe the physical features and method of formation of one of the
volcanoes and one of the rift valleys you have named in (a)
(Or Choose thre of the following landforms: jor, barrier ref, delta, lagoon. For each
i. With the aid of diagrams describe its main features and Suggest how the landforms may have
been formed.
ii, Name an example and locate it by means of a sketch map. (1967)
(a) With the aid of diagrams ana by reference to actual examples explain how lakes are caused by any nwo of
the followin
i, movement of theearthserust. i, glaciation, i
(b) Describe three ways in which lakes ae useful o man. (1966)
(a) With the aid of diagrams, describe the physical features ofa limestone region.
(0) Select any shee of these features and explain how they may have been formed
(©) Name and locate one large limestone region, (1965)
4. () Usingthe World Mapasa guide drawasketch map of either sia orSouth Ameria to show the distribution
i, fold mountain ranges i plateaux
(6) Describe typical features ofthese two types of mountains and explain how one type may have been formed.
Draw diagram to illustrae your answer (1964)
5. With the aid of explanatory diagrams and by reference 0 actual examples describe the physical features

the ation of man.

(a) acoastine whch includes Gord rias
(©) consi which includes sandbasor pits and lagoons (1968)
6. iter Choos vo ofthe following features: sand dune, canyon, det. For each ofthe wo:
(a) With the ai o diagrams, deseie its appearance and expla its formation
(0) Locat an area where an example can be found
Or Write an account of the glaciation of a mountain region (1962)
7. (8) Broly describe an active vlan
(0) Wat an earthquake, and ho its caused?
(©) Say why earthquakes and volcanoes ar often associated wih the same areas ofthe world, and foate mo
such res. (1961)
8, Choose mo ofthe coastal features ford, stacks, sand sis iss For eich you choose:
(@) With the aid of diagrams:
à, describes appearance
i, explain ts form
(0) Locate an area where an example ould be found (1960)
9. e) Say what you understand by he ter ocean current Sat bil how ocean currents are caused and
why thy are important,
(0) For er the North Allan Ocean
07." the North Pace Osean daw a simple sketch map 10 show the postions and names of the
principal curents and indicate whether they are warm or col. (1962)
10. Biker Sec fre of the following, and explain wit he ad of diagrams or maps how a ake may have
been formed
(G)_by a river in its lower course (i) by glaciation in highland areas
Gi byvokanicaction (ina fall 5 E de
(Or: With the aid of diagrams, describe thre of the following and explain how they have been formed:
spit, beach, coral ref, delta (1970)

# an

Chapter 13 Weather

The Difference Between
Weather and Climate

We don't hear people saying thatthe climate of the
day is warm or cold, but we do talk of warm weather,
a cold morning, a sunny afiernon, a rainy day or a
chilly night. Any casual remarks about the atmos
pheri conditions of a certain place at a certain time
fare about weather. I is never stati and thus cannot
be generalized. In the same country, even over a

small area, the weather can vary tremendously. It
may be sunny in one part of the district, but raining
heavily a few miles away. Strong gales may be
experienced along the cousts while the interior may
be relatively calm. It is important to realise that
any place can be subjected to haphazard changes in
weather at any tn

When we speak of we mean the
atmospheric conditions of an area over a considerable
time. For climatic averages, a minimum period of
35 years is desirable. This involves the systematic
observation, recording and processing of the various
elements of climate such as rainfall, temperature,
humidity, air pressure, winds, clouds and sunshine
before any standardization of the climatic
or averages can be arrived at. The climate of
Malaysia is described as hot, we, equatorial climate
Which is a summing up of the average everyday
mate ofthe country throughout the ear.

The in the climate or weather
of a country also differs. Generally speaking, the
slimate of temperate latitudes is far more variable
than that of the tropics The climate of the British

ikesisso chan
Conversely

at many people have commen
only weather
le say that

he climate of Egypt is so

makes a good deal of sense when peo

Egypt has no weather, only climate’

The Importance of Climate and Weather
The profound influence of climate and weather
over mans activities can be seen from his everyday
Forces of nature have regulated to a very great
extent the sort of food we cat, what we wear, how we
live and work. Our mental alertness, our physical
characteristics and even our racial differences when
closely examined have at least some relationship
‘with climate. The direcion of winds once controlled
the pattern of trading routes. The safety of modern
air communications is closely tied to accurate
meteorological reports from the ground stations.
Despite the advances made in science and technology,
farmers and their crops are silat the mercy of the
climate and the weather. Conditions of temperature,
precipitation and humidity may promote or dis
‘courage the growth of fungus and diseases which may
be injurious to both men and crops. Death rates
are normally high in tropical countries and low in
deserts, because germs are not transmitted readi
in regions of high temperature and low humidity
‘Cool, fresh mountain aris always good for heath,
Weather Bureaux or Meteorological Stations are
scattered all over the globe, including the oceans,
ing some of the most up-to-date weather instru.
ments to gather a wide range of data as raw materials
for the construction of

3

charts ‘Though men are still unable to tame the
Fores of nature such as foods droughts Iyphoons or
hurricane, a sound knowledge of the trends the
rather stems can often help to avoid or reduce the

seriousness of the calamities Profesional meteoro
Togiss arable 1 forest Ihe weather fur accurately

from local observations. A fall in the barometer, a
change of cloud types, a bright sunset or even a
Inhisper ofthe wind can be very useful tps toa weather

forecaster in detecting what i going 10 happen nex.
‘A casual glance at the sky will be suficiet for a
weber expert 10 sum up the conditions of the

atmosphere
Tod:

farmers are becoming more and more

ependant upon meteorological services À know
lodge of the likely weather of a place will be ul
fora farmer to plan his work fr th season or the
year Frequent agriulral bulletins issued by

Metcoropcal Of will asis farmers 10 take due

precautions against frost, hal, heavy snow

period of possible. drought

Sailors at sea

(©) Orsinary measuring cylinder

warned promptly of any on-coming gale or typhoon
Modern sir transport, militar

phical expeditions, even impor
often take due consideration of
reports À fair knowledge of the weather is not only

useful but often essential

The Elements of Weather and Climate

climate are normally
1. Raifal, Rainfall including other forms of pre

piton (now, sect and hail) is always measured
by a metal instrument called a rain gauge (Fig 9
Ie consists of a copper cylinder with a metal funnel
either 5 inches or 8 inches in diameter, which leads

into a smaller copper container or a glass bottle
‘Thebolein te funnel hat leads down to the container

is minimised, The gauge should be atleast one foot

(©) Acaltratodtapor measure

Splashing. The instrument should be sited wel
off or percolated away. For meteorological record

ings, is neck dof 24 hours
with at least 0-01 inch or more rain being recorded
IF the amount exceeds 0-04 inch, it is considered à

wet day Fo average rainfall
for Malaysia is less
torrential downpour can account for more than an
inch of rainfall The rain gauge must be
examined every day. In temperate regions, snowfall
is carefully melted by warming the funnel and the
measured. For all practical purposes 10 to 12 inches
of snow may be considered as equivalent to 1 inch
of rin

The daily records of rainfall wil be added at the
end of the month to find the total f

general reckoning, the
han 03 inch a day Only a

onth is again added at

the anual rafal

rom the aver
E period of say
ng in rainfall maps, places having
the same mean annual rainfall are joined by a line
sohyet as shown in many atlases. Rainfall
jcted as shaded rainfall

month. The total for each
the end of ı
The mean an

al take

called
can also be graphically de
columns, one for each month of the year as in Fig. 97
ams, one dot for each year for as

The former

or in dispersal diag

5 as posible as in Fig. 98
Vustates the monthly rainfall regime over a year and
the later shows at a glance the range of dry and

2. Pressure. Air is made up of a number of mixed
gases and has weight, It therefore exerts a pressure
fon the earth’ surface which varies from place to
place and from time to time. This force that presses
on the surface of any object can be fairy accurately
measured. The instrument for measuring pressure
is a barometer, as shown in Fig. 99, invented by the
scientist Galileo and his assistant Torricelli in 1643
The ordinary mercury barometer consists of a long
glass tube, sealed at the upper and open at the
Tower end. The lower end is inverted in a bow! of
mercury, whose surface is exposed to the air, Varia-
tions in the atmospheric pressure on the mer

surface are balanced by the column of mercury in the
alas tube. This gives the pressure of the air and ean

SEMAMJJASOND s

avr un

‘monte

Fa 87 A rainfal histogram showing
{he monthly rafal of Kota
Kinabalu. Malaysia,

Fig 98 A rainfall disperso! digram for
Gibraltar or 25 years

Fig 99 A mercury barometer

9s

e rad of quickly fom the sale on he gas tbe.
Ry lil cold be sd foc this purpose, bt mercury
An bn chosen base the heaves gud known.
Mr ma water were wad, the comsponding
Chime ar nomal atmospheric pressure would be
Se At so Inc. the mercury colmo is 299
ines or Zn If the pre ees th
ening on the surface wil free up the mercury
om o about 31 inches (igh presse). Wien
fhe proms decreases as Is air press on the
rc ie mern corn wl drop about 28 inches
Glow presa. Ar pure is a iors I À more
Appropriate o mesure tin terms ofa unit of force.
‘Roc unit Known asthe mir (m) was adopted
by mecorolgc! tions in 1914. À normal tmos-
Phere presureeguhaln 0147 persquaeinchin
sh or a reading of 299 inches of mercury in he
Column is 1013 milibars On maps places of equal
rsa are joined by lines called Gotas In
Tempe ttes presre changes are very rap
in the formation of cyclones and antcclones. In
"normal Greumsances they vary from 960 mb 19
100m

Fresa eaings vary with a numberof factors
‘selene! fading of 30 inches will be baled on
nouns regions of 35 miles above sea eel
This is because a one and thee es ir above
and so the weight, or prow 10% The barometer
is año semi to gravitational foros at diferent
Tice The mercury Het alo expands with an
increas in tempera. Therefore for profesional
métrologie work which requires very accurate
readings, corstons fe o be made in respect of
td, latte and temperature.

Since a mercury barometer that dips in iuid
mercury is
mor po

ern

Fig 100 An aneroidborometor
the pilot wll be able to tell the altitude of the plane
above sea level, For a continous record of pressure
changes, as is sometimes required, the sl-recording
barogram is used.
3. Temperature. Temperature is a very important
element of climate and weather. The instrument
for measuring temperature is the thermometer which
isa narrow glass tube filed with mercury or alcohol
Tt works on the principle that mercury expands when
heated and contracts when cooled, On thermo:
meters, temperatures are marked in one of two Ways
In °F. (Fahrenheit) the frezing-point is 32°F. and
the bolling-point is 212°F For most scientific
‘purposes the Centigrade °C. scale is prefered. Is
freezing point is 0°C, and its boiling point is 100°C.
“The mean daily temperature of Malaysia is 80°E oF
267°C. For rapid conversation of one scale into
another, he following formulae may be used.
To obtain Fahrenheit = (18 x °C) +32.

ci:

To obtain Cenrigrade= (°F -32)21:8

‘eg. to convert SI. into Centigrade:

(59-32-18 = 27-18 = 15°C,

As the degree of ‘hotness’ varies tremendously
from one place to another, the sting ofthe instrument,
is very important. A temperature taken in open
daylight is very high, because it measures the direct
insolation of the sun. It is better described as
“temperature in the sun, For agricultural purposes.
‘earth temperatures are taken at various depths in
the ground. The thermometer is enclosed in 2
special glass tube and the bulb is embedded in
para wax, so that they are less sensitive to abrupt
temperature changes. To assess the possible damages

=a

Fig 101 A Stevenson Screen

done by ground frosts to crops in temperate latitudes,
gruss temperatures are also tke

But the temperatures that we are so accustomed 10
in eimatic graphs ae shade temperatures. that is the

temperatures of the ai, Preautions therefore must
be taken to exclude the intensity of the sun radiant
cat. This is done by placing thet

standard. meteorological shelter known as Ihe
Stevenson Sereen (Fig. 101). It consists of a white
‘wooden box raised 4 fect above the ground on stilts
“The roof is double-layered with an intervening air
space to exelude much of the direct rays of the sun
‘The sides of the box are louvred like "venetian blinds
to allow free circulation of the ir. One side of the
screen is hinged to serve as a door which can be
‘opened and closed to give access 10 the instruments
kept inside. The floor of the screen is also louvred
‘The Stevenson Sereen normally caries maximum and
minimum thermometers, dry and wet bulb thetmo-
meters. Larger ones may also contain a selbrecord-
ing thermogram and bystogram.

Maximum and minimum temperatures are mea
‘sured by the maximum and minimum thermometers
‘They are either in the form of separate thermometers
or joined in a U-shaped glass tube as in the Six
thermometer. The maximum thermometer records
the highest temperature reached during the day.
‘The mercury in the closed glass tube expands when
the temperature rises It pushes a metal indicator
"up the tube and ths stays atthe maximum level when
the temperature drops. The end of the indicator
rarest the mercury as indicated in Fig. 102, gives

the reading of the maximum temperature, which is
STE. inthis case. To reset the mercury for the next
days read i hard or draw the indicator
back by a magnet

The minimum thermometer records the lowest
temperature reached during the day; it probably
‘occurs in the middle of the night or early in the
morning, The glass tube is filled with alco
which allows the indicator to slide freely along the
tube, When the temperature drops. the alcohol
contracts and drags the indicator towards the bulb
by the surface tension of the indicator. When the
temperature rises, the alcohol flows past the indicator
leaving it where it was. The end of the indicator
farthest from the bulb gives the reading of the
‘minimum temperature, which is 73°F. in Fig. 102

Fig 102 Maximum and minimum thermometars

“he themomee i then rst by a magnet fr the
10024 hour ding
Tn record temperature maximum tempera:
ture nen inte colo forthe pens dns
fed the minimum tenpertre inthe column for
Uren day bre of the repent pet of
probable Sue: The mean dl tempe
cora of maximum and minum eg. (7 +
DE) 2 = AE Hat an courte mean souls
RU eg of 24 reads en a hour intervals
Goring the whole dy. In pace this almost
imposible cept wih scoring instrament.
TR An Dann de mm a mm,
epee of day ges ie dural range 0
ou ‘The difference between the hottest
from Le Ja i the nor nis) and he
cles month Ge. Jay inthe northem emi
She) ges the anal range of tempe
in dagramate represents, monthly mean
tempera ae show in imp empata gal
(3 10) of in tempera disse maps as
otre For these maps temperatures ae reed
4 do at i shown a6 I the org

in grams per cubic metre, is called the absolute
M QE weather sods is the rte huni
Tats Wera betwee te cta ;
Thott and US toll amet ie ar can held at à
ennemie expensed a «presage. Warm
cere on tn oa. wi
Fe neg ee Ta de ann

ter vapour as it can carry. When the relative
humidity reaches 100 per cent the air is completely
saturated. The air temperature is said to be a
Sew-point. Further cooling will condense the water

vapour into clouds or rai. Iti thus clear that when
relative humidity is high the air is moist, as in the
‘equatorial regions; when tis low, the air is dry as in
te des.

‘The instrument for measuring relative humidity
is the hygrometer, which comprises wet-and dry-bulb
thermometers placed side by side in the Stevenson
Screen (Fig. 104). The dry-bulb i, infact, the ordi
‘ty thermometer that measures the shade tempera
ture mentioned earlier. The wetbulb is kept wet
by a wick that dps into a reservoir of distilled water.
When the air is not saturated evaporation, which
produces a cooling efect, takes place from the moist
Wick. The wet bulb therefore always shows a lower
reading than the dry bulb, With reference to prepared
tables for calculating relative humidity, under the
difference column of the dry and wet bulb reading,
the relative humidity can be obtained asa percentage.
‘Normally tage difference indicates a low RH. and
small diference a high R.H. If both have the same
reading, RH. is 100 per cent; the air is saturated,

5, Winds. Wind is air in motion and has both
direction and speed. Unlike other elements in
climate such as rain, snow or set, winds are made
Up of series of gusts and eddies that can only be

pers

fat but not seen. When
dust

blowing. But there à
show or measure unless we make use

The instrument widely used for
direction is a wind vane or we
direcion is always blocked b
weather cocks and wind
in an exposed position, t
It is made up of two paris as sho
(a) and (b). One part
Which is free to move with the prevailing. wind,
The other part with the four compass points is
stationary and shows in which direction the wind is
moving. Winds are always named from the direcion
they blow; an east wind is one that blows from east
to west and a south-west wind is one that blows
from the south-west.

Most of the weather cocks that we see on church
spires and country buildings seldom give a correct
indication of wind directions They are either too
low or are blocked by taller structures nearby
‘The direcion of smoke-dift or flag movements in
fairly open spaces provides the most reliable indica-

g ind
AS wind

es and all buildings,
nes need to be erected
gel à true diretion,

in Fig. 105

Bottes ri ana
pos it ha Wh

Fig 106 Simplified sketch to ilustat the main features
fa ind anemometer

tion of win direcion: Sometimes apiece of woven.
(dor with tals xed tothe top of à high pole and
dite fresh in mir This 6 another way of
indicating wind direction

The speed of wind is usualy measured by an
anemometr (Fig, 100) consists of three or four
semicircular cups attache to he ends of horizontal
Spokes mounted on a high vertical spindle. As
the conca sides ofthe cups oler greater resistance
to the winds, the horizontal spokes will rotate
moving à central rod which transmits the velocity
(speed) ofthe wind in miles per hour to an electrically
operated dl. But the sped recorded isnot absolute-
Iy accurate because afer the winds have abated, the
rotation continues due to its own momentum,
With some modifications, the anemometer can also
record wind directions

Since an anemometer is not easily avaiable, à
lle practice of local wind observations wil help us
to asses the speed of winds By seing the way some
objets move a great deal can be said about the
Strength of winds The best guido is obtainable
from the Beaufort Wind Scale which was devised
by Admiral Beaufort in 1805 for estimating wind
speed. Frequent reference tothe table in your fee
time will ep you to learn quie
6. Sunshine, As mentioned in Chapter 1, the
amount of sunshine a place revives, depends on the
Seasons a facor determined by latitude and by the
Position of the earth ints revolution around he sun,
“Tours resorts, particularly in the higher temperate
Initudes, are mos concerted about the numbers of
ours of sunshine they recive In the top, where
sunshine is abundant people are Tess interested in
theamount.

In the meteorological station, sunshine duration
js recorded by a sundial, 4 inches in diameter,

9

‘The Beaufort Wind Seale
Beaufort Arrow Wind Speed Bes
SeileNo, Indication Description (mph) (a guide to observation)
o Calm Less than | Smoke rises vertically
1 Light air 1 Wind direction shown by smoke

Breeze

Slight Breeze 47
Gene Breeze 8-12
Moderate 1518
rsh Breeze 1924

Strong Breze 25-31

but not by wind-vanes

Wind felt on face; leaves rustle; vanes
moved by wind

Leaves and twigs in constant motion
winds extend light Nags

Raises dust and loose paper small
ches moved

Small trees in la? begin to ovay; crested
‘wavelets form on inland wate

Large branches in motion; whistling
heard in telegraph wires

7 Moderate 32-38 Whole tree in motion; walking incon
Gale venienced
FreshGale 39-46 ‘Twigs broken off toes; progres generally
impeded
9 Strong Gale 47-54 Slight structural damage oocurs, chimney
pots removed
10 Whole Gale 55.63 Considerable structural damage, tees
uprooted
" Storm 6475 Widespread damage, very rarely ex
perienced
12 Hurricane Morethan 75 Widespread devastation, experienced

Pierre

through which the sun's rays are focused upon a
sensitized card, graduated in hours. À line Is made
‘onthe ard when tis sul Hate, but ot when
the rays are faint. On maps places with equal su
Shine duration are joined by ish
7. Clouds. When ar ries, itis cooled by expan-
Son. Alter dew-point has been reached cooing
leads to condensation of water vapour in Ihe amor.
‘here. Tiny dropes of water vapour which are 100
“mal 10 fl rain or snow (es than 0001 cm,
approximately 00005 inches in radis) wil be
Suspended in the air and flat as clouds. Their
e ‚height and movements tell us a great
9 mins nd weather e ae
ce It is fascinating and ery re
something about the clouds which
For meteorological purposes,

onlyin tropical areas

the amount of clo in the sky is expressed in
ieh oktas (eg. 28 O is quarter covered;
ABO is half covered; 6/8 ® is three-quarters ob-
scured and 8/8 @ is completely overcas.) They
are shown on weather maps by dies, shaded in the
correct proportions. Details of cloud type are
indicated in code figures which have been interna“
tionally accepted. On maps places with an equal
degree of cloudiness are joined by lines known as
isoncphs As clouds vary so quickly from time to
{ime at any particular place isoneph maps have little
significance.
‘The classification of clouds is based on a combination
of form, height and appearance. Four major cloud
‘types and their variations ean be recognise.

(a) High Clouds: mainly cirus (Ci) of feathery

form at 2040000 feet above ground.

Cirus cloud
Royal Netherlands
‘Meteorological
store

Cirrocumulus cloud
‘National Pars

y € PA - —

1. Cms (G This looks fibrous
appears ike ips the blu sky: it often
fled “mares tis It indates fir we
thet and often gives brilant Sunset

5 This appears as
e globular mises, forming ripples in a

wi
“mackerelsky

Tit Cirostratus (Cs) This resemble
thin white she or vil the sk looks milky
and thesun ormmoon shines through t with
characteristic alo

(0) Medium Cloods mainly alto(Alormidle-
heit clouds at 720,000 Fee.

ih Altcumales(AI-Ca) These are woo!
fy, bumpy clouds arranged in layers and
Appearing like waves inthe blue sky. They
‘normally indicate fine weather.

Y Altestratos (MES) These are dene
greyish clouds with a water look. They
fine a fibrous or tated structure through

D tes tine iy

(©). Lam Clouds mainly status or sheet clouds

below 7.000 fc
sl Stratcumules(SI-Cu)Thisisaroush,
bumpy cloud with the waves more pro-
nounced than in altocumulus. There is
rat contrast between thebrightand shaded
parts

Altocumulus cloud Royal Netherlands Metrologic
‘ou oy gica

vii, Status (SD This i very low cloud
y and thick, which appears

niormy er
Ie brings

like a low à

dull weather with

evil of aircraft and is thus ad
i Nimbostratus (SiS) This sa dark
dull cloud, clearly layered, and is also
Known as à rain lud, I brings cont
uous rin, snow or let.

(@ Choa with great vertical extents m

malus or heap clouds with no definite height

x. Caml (Cu) This sa verti
with a rounded top and horizontal b
ns associated

omectional currents. ts
white globular masses may look ee
nstihesun but tsa fair weathe

% Cumulonimbus (Cu-ND This isin ct
own eumulus cloud, extend
for a tremendous vertical height from a
000 feet 10 over 30.000 fee, Its
black and white globular masses take a
fantastic range of shapes. ts caulilower
top often spreads out like an ami This is
frequently seen in tropical afternoons. It
is also referred to as ‘thundercloud and
brings consctional ram, accompanied by
lightning and thunder

Cumulus cloud Y Mondoine

‘Cumulonimbus cloud Royo! Netherlands Meteorological

Institute

105

8. Other Elements pertaining to visibility, Otber
elements acting visbiliy include haze, mist and

a Haze This is caused by smoke and dust
parte in ns arcs or maybe duo uncqual
‘eration of ight in ir of diferent denis in the
Toner atmosphere The tem is usually ued in
comision mh the ection of slit in regions.
for humilis Js than 75 por cet, When sity
Gales than He ze pren.

{@) Mist The condensation of water vapour in
dh ar causes sal droplets of water to ot about
forming loads at ground tee cal mst. I
lues visa o about 1000 mets or 1100
ards Unit hare mit oe in ls when the
Fe mii over 75 percent.

{© For Ordinary fog de to water condensing
on ust and her paris lik smoke fom houses
and tan ny our te Ws: ts of

amosphee as a sort of dense ground nd
Sy in fg seen ls than 1.00 meres

Snare, ke hoe of the Blak Country
‘and northern England, very thick smoky fog is

ied led 08. Te vty may be reduced

220 ars en ess.

Fog thi occur on fils are call ill Los

"e mos common in e morning, even inthe
‘and pers when the sun res I tempera
ans when das ar hot and nights are clear and
sil, fogs may also result from cooling of the land

conaet witha cold current
BI
ese os reo shallow

mats of ships can be sen ro

1.6) What instruments are normally Kept in
We shop venir station?

D Wp import that he des of

rain and te mao of re
coring soul be unorn?

(9 Ean at pressions you would

(© Ne to cure iat your obenations

find eons fom te various est

2, Name the instruments you would use to
‘measure the following elements of climate
(relative humidity
(b) atmosphere pressure
(©) wind velocity
For any neo of the above, and with annotated
diagrams, explain how the instruments work,

3. What weather clement are measured by the
following apparatus?
(9) a rain gauge
(0) the Sixs maximum and minimum
thermometers
(6), a wind vane
Describe how the above apparatus function
and state what special precautions must be
taken when taking readings from them.

4. Either: Explain the following
(a), Wind speed at 2,500 fet is greater than
that a the surface,
(0) Britain has no climate only weather
(©) Fogis in fact, loud at ground level
Or: Distinguish between,
mist and fox
‘ius and stratus clouds
climate and weather

5. Define any three of the following terms or
ee) resin un
(b) di

Chapter 14 Climate

The Atmosphere
‘The atmosphere is made up of gases and vapour,
and receives incoming solar energy from the sun
ving rive to what we cll climate. We actual live
A the bottom of this indefinite layer of atmosphere
Are the air is densest. Higher up, the air thins
out and iti sill à matter of conjecture where the
Stmosphere ends One estimate puts thi limit at
about 600 mies above sea level. The lowest layer,
in which the weather is confined, is known as the
troposphere. I extends from the earth’ surface for
a height of 6 miles, and within it temperature normally
falls with increasing alitude. The climatio elements
such as temperature, precipitation, clouds, pressure
and humidity within the troposphere account for
the ret variations in local elmate and weather that
play such a great part in our daily lives. From
Analyses taken in different pars of the globe, it
found that the lower part ofthe atmosphere contains
‘consistent proportion of certain gases: 78 per ent
of nitrogen, 21 percent of oxygen, 0.03 per cent of
carbon dioxide and minute traes of argo, helium
and other rare gases In addition, it has an un-
predictable proportion of war, existing either as a
ES like water vapour, a liquid tke rain, clouds and
Stet or a old ike snow and Ratones, as well as
Other solid particles Tike smoke and dust It à
because of the variable water content of the atmo-
sphere that we have such grat contrasts in weather
and climate over diffrent parts of the word. If we
were 0 live in a dry atmosphere, absolutely without
Water there would be no weather and not even
much climate
‘Above the troposphere lies the Sraosphere or
‘the upper layer of the atmosphere It extends upwards
for another 50 miles or even more. It is not only
‘ery cold, but cloudless, with extremely thin air and
without dust, smoke or water vapour but tere are
marked seasonal temperature changes Beyond the
Stratosphere the lonospiere which goes several
undred miles up. It has electrically conducting
layers which make shortwave radio transmission
‘over long distances, Modern artificial satel
| RSR
ballons ae ued o transmit back to earth
formation regarding the conditions of

FR

Insolation
The only source of energy for the earths atmos:
here comes fom the sun which has à surface tem
perature of more than 10SO0PE This energy tels
Through space fr a distance of 93 milion mies and
reaches us as solar energy or radiant energy in the
process called insolation. This radian from the
Sun is made up of three parts, the visible hit Bt
that we se when the sun shines and the less Yi
raie and infra rays The visible “white
lights the most intense and bas the greatest influence
on our climate. The ultra-violet rays affect our skin
and cause sun-bum when our bare body is exposed
to them fr too long a period. The infrared rays can
penetrate even dust and fog and are widely used in
‘Photography. Only that part of the sun radiation
‘hich reaches the earth called isolation.

What mates most is he eet of the atmosphere
upon the incoming solar radiation. Ts estimated
that of the total radiation coming to us, 35 per cent
reaches the atmosphere and is dire ‘elected
track to space by dist, clouds and aie molecules u
plays practically no pat in eating the earth and is
mosphere Another 14 per cen i absorbed by the
ater vapour, carbon dioxide and other gases. Its
interception by the ai causes it 10 be scattered” and
“dised” so thatthe visible rays of the spectrum
between the ultraviolet and inated give set the
characters blue sky that we see above us The
remain SÍ per cen reaches the earth and warms
the surface. In tum the earth warms the layers of air
above it by dret contact orconducion. and through
the transmision of heat by upward movement of air
«amen or comecton, ‘This ration of heat by
the earth continues during the night, when insolation
fiom the sun cannot replace it. The carth-surface
therefore cools at night.

“The ate of beating differs between land and water
surfaces Land gets heated up much more quickly
than the water. Because water is tramparent heat
is absorbed more slowly and because itis always
in motion, its absorbed hat is distributed over a
greater depth and area. Thus any apreciable rise
in temperature takes a much longer tine. On the
‘other hand the opaque nature of land allows greater
sorption but all the radiant heats concentrated at
the surface, and temperature rss rapid, Because

105

ofthese differences between land and water surfaces
Hand also cools more quickly than water.

Elements of Climate
“and Factors Affecting them

‘Of the various climatic cements temperatur.
recitation, pressure and winds are the most
“important becawe of her far racing. lol
fuer The cements and their distribution
bebe Borional fom equatorial to polar regions
fr eral from ground to amospher ae in one
‘ray or another flected by some or all ofthe climate
factor tud alitude continental, ocean cur
‘ents isolation, prevailing wins. slope and aspect,
‘tral vegetation and od.

‘Temperature
‘The importance of Temperature
1. Temperature influences the actual amount of
(er vapour present in the air and thus decides the
ing capacity of the air.
Ii decides the rate of ciaporation and condensa-
D see ra stes of sty

beamosphere
As relative humidity i direc related to the
ofthe air affects the nature and types of
cows formation and prespitation.

temperate latitudes on su

line ver
Fetch trough a sorter distance and is one
Tita solar insolation eats up a smaller sure
trea: temperature is thos high. On the

RZ trl though a linger distance and mich of i
feat à absorbed by clouds, water vapour and das
paris is oblique ay as to hat up a ar are
pers heeore low

Ltée. Sine the atmosphere is mainly hats
fp conducion from the ear, it can be exposed
that places nearer 1 the earth’ surf

than those higher up. Thus temperature decreases
with increasing height above sea level. This rate
of decrease with altitude lapse ate) is never constant,

varying from place 10 place and from season to
season. But for all practical purposes, it may be
reckoned that fall of 1*E occurs with an ascent of
300 fect or 0.6. per 100 metres It is usually more
in summer than in winter. For example in temperate
Jattudes in summer, an ascent of only 280 feet will
cause the temperature to drop by 1°F, whereas in
‘winter it requires 400 feet, Similarly, the lapse rate is
greater by day than at night, greater on elevated
highlands than on level plains In tropical countries
‘where the sea level temperature is 80°F, a town that
islocated ata height of 4,500 fet (shown as X in Fig
108) will record a mean temperature of 65°F.
3. Continentality: Land surfaces are heated more
quick than water surfaces, because of the higher
specific heat of water. In other words it requires only
‘onethind as much energy to raise the temperature
‘of a given volume of land by 1°F. as it does for an
‘equal volume of water. This accounts for he warmer

Reon
min

a
A

Fig. 109 The warming effect of warm ocean curents
and prevaling winds on coastal regions with
{Marie cimatein temperate attudes

summers, colder winters and greater range of tem:

perature of continental interiors as compared with

‘maritime districts

4. Ocean currents and winds. Both ocean currents

And winds affect temperature by transporting their

heat or coldness into adjacent regions (Fig. 109)

(Ocean currents like the Gulf Stream or the North

“Atlantic Drift warm the coastal districts of western

Europe Keeping their ports ice-free. Ports located

in the same latitude but washed by cold currents,

such as the cold Labrador Current off north-east

Canada, are frozen for several months.

(Cold currents also lower the summer temperature,
particularly when they are carried landwards by
‘onshore winds. On the other hand on-shore Wester-
lies convey much tropical warm air to temperate
‘coast, especialy in winter. The Westelies that come
o Britain and Norway tend to be cool winds in
summer and warm winds in winter and are most
valuable in moderating the climate,

Local winds eg. Fohn, Chinook, Sirocco, Mistral,
also produce marked changes in temperature.

5. Slope, shelter and aspect. À sep slope ex

Perienoes a more rapid change in temperature than

a gente one, Mountain ranges that have an cast

‘west alignment like the Alps show a higher temper-

tur on the south-facing sunny slope’ than the north

facing ‘sheltered slope’. The greater insolation of

‘the southern slope is beter suited for vine cultivation

ys “Y

Fig. 110 Southfocing slopes:

Fig. 111 Temperature inversion at valley bottom on a
calm, sil night e.g. an Alpine valley in
Spring
may then be lower in the valley than higher up as the
slopes as show in Fig. 11. À reversal of the lapse
rate has taken place. This is called a temperature
6. Natural vegetation and soil. There is a definite
diference in temperature between forested regions
“and open ground. The thick foliage of the Amazon
jungle cuts off much of the in-coming insolation
“and in many places sunlight never reaches the ground.
Its in fact, cool in the jungle and its shade temper-
ture sa few degrees lower than that of open spaces
in corresponding latitudes. During the day trees

‘nist and fg may form.

Light sos reflect more heat than darker soils
which are beter absorbers. Such soil dierences
ima sve rie to slight variations inthe temperature
region.

Asa bo, dy soi like sands ar very sense to
temperature changes wheres wet sols, ike cl
foun much moiture and warm up or cool down,
mor sow

107

Precipitation
‘Types of Precipitation. 7 ai is suis cooled
delos dew-pont tiny drops of water vapour will
condense around dust patios When they fost
about as mases of mine water droplets orice
rss at a considerable hight above sa lee,
they form sos irs cumulus or satus. When
‘ondenstion occur at ground Incl without neces
Sanity resulting in rain, ars, mis or fo are formed
in higher latitudes or aliado where condensation
‘of water vapour may take place in the atmosphere a
temperature below Fering point, sow fl, either
as feathery Makes or individual ce erysals Ifthe
Amos air ascends rapidly 1 de cooker layers of the
mosphere, the water droplets freeze into ce pels
And a to the earth as hal or alone. As more
And more supercooled water drops accumulate
‘foun a alone, increases steadily in is some
“of them weigh as much as uo pounds I à ere
the stones do reat damage to crops
‘buildings. Very often, the ice-pellets exist as
frozen raindrops, meling and rein on the
‘down; this forms et. I is only when the
sin clouds coalesce into larger drops between
mm. and 6mm. that rin alls

rainfall.
a Comvectional rainfall. This type of ranfllis most
common in regions that are intensely heuted, either

Higher. Air rises in a conection cu
prolonged period of intense heating (Fi
ascending, lis water vapour condenses
Tonimbus clouds with a great vertical extent
probably reaches its maximum in the afternoon wi
the convetional system is well developed. Hot, rising
air has great capacity for holding moisture which
is abundant in regions of high relative humid,
As the air rises it cools and when saturation point
reached torrential downpours occur, often accom
panied by thunder and lightning. The summer showers
in temperate regions are equally heavy with ocea-
sonal thunderstorms. These downpours may not
be entirely useful for agriculture because the Fain is
so intense that it does not sink into the sol but is
rained off almost immediately

2. Orographic or reli rain. Unlike consectional
rain which is caused by conection currents, oro
sraphic rain is formed wherever moist air is forced
to ascend a mountain barrier Its best developed on
the windwurd slopes of mountains where the pre-
‘ailing moisture-laden winds come from the sea. The
air is eompeled to rise as shown in Fig. 113, and is
thereby cooled by expansion in the higher altitudes
and the subsequent deereae in atmosphere pressure
Further ascent cool the ai until the ir is completely
Saturated (relative humidity is 100 per cent). Con-
<ensation takes place forming clouds and eventually
‘in, Since it is caused by the relief of the land, its
also known as relief rain. Much of the precipitation
‘experienced onthe windward slopes of the north-east,
of West Malaysia, western New Zealand, western
Scotland and Wales and the Assam hills of the
Indian sub-continent, i reli rain,

ols a

Fig. 114 Cyelonie
or frontal rai (depression)
(a) The convergence of

(On descending the leeward slope a decrease in
alttude increases both the pressure and the tempera
ture, the air is compressed and wurst, Conse-
quently, the relative humidity will drop. There is
exaporation and lite or no precpitation. The area
in the lee of the hills is termed the ruin shadow ara
‘The effects of ruin shadow are felt on the Canterbury
Plain of South Island, New Zealand and the western
slopes of the Northern and Central Andes and in
many other areas

3. Cyclonic or frontal rain. This type of rainfall
is independent of relist or convection. It is
purely associated with eyclonic activity whether
in the temperate regions (depressions) or tropical
regions (yelones). Basically is due to the conver

fence (meting) of two different air masses with
diferent temperatures and other physical properties
{AS cold air is dense, it tends to remain close to the
ground, The warm air is lighter and tends to rise
over the cold air as shown in Fig. 114. In ascent,
pressure decreases, the air expands and cool,
fondensation takes place and light showers called
scie or frontal rain occur, The heavier and colder
air masses eventually pushes up the warmer and ligh-
era and the sky ler again.

Pressure and Planetary Winds
‘World pressure belts. We studied in Chapter 11 the
relation of waters inthe oceans and noted that they
follow a regular patter, flowing from the poles
‘€quatorwards and from the equator polewards Inthe
‘Sime way, there is also a circulation of air over the
of the earth caused by the differences in

(0) Warm ar rises over cold ar
{yelonie rin occurs

(6) Cold air eventually pushes up
Warm air and the sky is cl
oan

south, is the Equatorial Low Pressure Belt, where
theres intense heating, with expanding air and ascen-
ding convection currents This equatorial belt is
often termed the Doldrums, because sailors in the
‘olden days often found themselves becalmed here
Aix a zone of wind convergence

About SUN, and S, occu the Sub-Tropical High
Pressure Belts where the air is comparatively dry and
the winds are calm and light. I sa region of dessen“
ding air currents or wind divergence and antieyclones.
tis fequentl referred to asthe Horse Latitudes

Around the latitudes G0*N, and S. are two Tem-
perate Low Pressure Belts which are also zones of
Comergence with eyelonie activity. The sub-polar
low pressure areas are best developed over the oceans,
where temperature diflerences between summer and
‘winter are negligible

[At the North and South Poles ON. and S. where
temperatures are permanently low, are the Polar
High Pressure Belt. Unlike the water masses of the
high latitudes in the southern hemisphere, igh
pressures of the corresponding latitudes in the
"northern hemisphere are a litle complicated by the
presence of much land. Some pressure differences
between summer and winter can be expected.
The planetary winds. Within this pattern of per-
A manent pressure belts on the globe, winds tend to
lo from the high pressure belts 1 the Tow pressure
bolts as the planetary winds Instead of blowing
direct from one pressure belt to another, however,
the effet of the rotation of the earth (Coriolis
Fores) tends to delet the direction of the winds,
In the northern hemisphere, winds are defected 10
thir righ, and in the southern hemisphere 10 their
{eft as shown in Fig, 115, This is know as Ferri

109

descending
Seuth Polo

Fig. 115 The distribution of world pressure bols and
© planetary winds

Lar of Dein Me ors Fo shen
long the equtor ut increases progressively towards
‚For is reason, winds blowing out from the Sub.

Ben
==

South-East Trace Wings
ws

Nort-Westeries (variable)
ws

Polar Eastertes

in the southern hemisphere, They are more variable
in the northern hemisphere, but they play a valuable
ole in carrying warm equatorial waters and winds to
Western coasts of temperate lands. This warming
effect and other local pressure differences have re
sulted in a very variable climate in the temperate
zones, dominated by the movements of cyclones and
antiyelones. In the southern hemisphere whet

theres large expanse of ocean, from 40°S. to 60'S

Westerlies blow with much greater force and regu.
larity throughout the year. They bring much prev

pitation to the western coasts of continents. The
either is damp and cloudy and the seas are violent
and stormy. I is thus usual for seafarers 10 refer 10

the Westelies as the Roaring Forties, Furious
Fifies and Shrieking or Stormy Sisies, according
‘othe varying degree of storminess inthe latitudes in
hich they blow.

I must be pointed out that not all the western

‘coasts of the temperate zone receive Westeries
throughout the year. Some of them lke California,
Tera, central Chile, southern Africa and south
western Australia recive Westelis only in winter

ee:

da
paris

= — =>

Fig. 116 Tho shiting of the pressure and wind bolis
in the northern hemsphore—showing thet
Boston summer ard wae and

overhead at midday in diferent parts of the earth

at diferent seasons. The entre system of pressure
and wind belts follows the movement of the midday
sun. In June when the overhead sun is over the Trop
of Cancer, all the belts move about 5*-10* north of
their average position. The “Mediterranean” parts
of the southern continents then come under the in-
fivence of the Westerles and receive rain in June

(winter in the southern hemisphere). In the same

manner, when the sun is overhead at the Tropic of

Capricorn in December, all the belts swing 5°10"

South oftheir average position. The ‘Mediterranean

parts of Europe and California then come under the

Influence ofthe Westelis and receive rain in Decem-

ber (winter in the northern hemisphere). This is

¡lustrated in Fig. 116.

Lastly, mention must be made of the Polar Enster-
lies which blow out from the Polar High Pressure
Belts towards the Temperate Low Pressure Belts
‘These are extremely cold winds as they come from
te tundra and icecap regions They are more
regularin he south than inthe north,

Land and Sea Breezes and Monsoons
Land and sca brszes asin fact, monsoons on a
smaller cal Both are taal cused by dile
tal heating of and and ses, the former in dural
‘hth and the ater in seasonal yt.
During the dy, the land gets heated up much
far han he, rn ar ss min me
low presse The se remains compara
‘ool with a higher pressure so a sa breeze Mom
om sca to land. Its speed or strength beeen
5-20 mph. and is genealy stronger in topical
lan. temperate regions. Its influence does not
ceed 15 mis from he out, most

a

AX night the reverse takes place. As the land cooks
(down much faster than these, the cold and heavy ir
produces a region of local high pressure: The sa
conserves its heat and remains quite warm. Its
pressure is comparatively low. À land brecse thus
blows out from land to sea. Fishermen in the tropics
often take advantage of the out-going land breeze
and sail out with it. They return the next morning.
with the in-coming sea breeze, complete with their

‘itch, Land and sea breezes are ilustrated in Fig. I
Indl

same way. monsoons are caused. Rapid
in the hot summer over most parts of India
imple induces heated air to rise The South
Monsoon from the surrounding. ocean is
attracted by the low pressure over the land and Blows
in. bringing torrential ain o the sub-continent.

Similar, in winter when the land is cold, the
surrounding ses remain comparatively warm. High
pressure is erated over Indo-Pakistan and the Norzk-
Fast Monsoon blows out from the continent into the
Indian Ocean and the Bay of Bengal

Fohn Wind or Chinook Wind
Both the Fohn and Chinook winds are dey winds
experienced on the leeward side of mountains when
descending air becomes compressed with increased
pressure The Fohn wind is experienced in the valleys
Of the northern Alps, particulary in Switzerland in
spring. Chinook winds are experienced on the eastern
slopes of the Rockies in USA. and Canada in winter:

‘Asillustated in Fig, 113 air ascending the southern
slopes ofthe Alps expands and cools Condensation
takes place when the air is saturated. Rain and even
snow fal on the higher slopes

Fg. 117 (a) Sea breeze (day)

er

>

Wen, CA
a

6 Land breeze (night) ze

|

Im descending the northern slope. the wind expe
lens an increase in presure and temperature
Tie ar à opened and warmed. Most of is
moisture is ost and the wind reaches the valle bottom
sa diy hot wind the Fohn. It may raise the tem-
erature by 15° to 30°F, within an hour! It melts
Sow and causes avalanches In North America it
iS called Chinook, meaning ‘he moweuier. But
it as ts blessings to, it hastes the growth of crops
“and fits and thaw the snow-covered pastures
the Rockies the Chinook has been known to raise
temperature by 35 within 15 minutes! The occur
ence of frequent Chinooks means winter is mid

Cyclonic Activity
"Tropical cyclones, typhoons hurricane and tornadoes
All these are diferent kinds of tropical cyclones.
‘They are wel Gecloped low presure systems into
which violet winds blow. Typhoons occur in the
(China Sea; topical cyclones in the Indian Ocean;
“hsrricanes inthe West Indian islands in the Carib
"bean; tornados in the Guinea lands of West Africa,
¿and the southern USA. in which the local name of
Wind is often applied, and villes occur
“in north-western Australia.

‘Typhoons oecur mainly in regions between 6°
land 20° north and south of the equator and are most
frequent from July to October. In extent, they are
Smaller than temperate cyclones and have a diameter
of only 5010-20 mies, but they have a much steeper

‘Tropica storm Judy off South Est Asi Royal Observa-
‘ory Hong Kong

Fig: 118 A tropical eyclone—a hurricane in the West
Indice

pressure gradient, Violent winds with a velocity of
‘over 100 m phare common. The sky is overcast and
the torrential downpour is accompanied by thunder
and lightning. In the wake ofthe typhoon, damage i
widespread, eg. in 1922, a typhoon that hurled huge
aes onto the Swatow coast drowned 50,000 people

The other tropical cyclones have similar character
isis and dir, perhaps, only in intensity, duration
and locality, Hurticanes have calm, rales centres
Where the pressure is lowest (about 965 mb) but
around this “eye”, the wind strength evcceds force 12
of the Beaufort Seale (75 mph.) (Fig. 118). Dense
dark clouds gather and violet stormy weather lasts
for several hours. A terrible hurricane struck Bar-
ados in the West Indies in 1780, which nearly des
{toyed the whole island, tearing down buildings and
‘uprooting ‘trees About 6,000 inhabitants were
reported dead,

“Tornadoes are small but very violent tropical and
‘sub-tropical clones in which the air is spiraling at
4 tremendous speed of as much as 500 mph: A

sucha
explode. T
Misisipp
Cyelones. These are better known as depresions

and are confined to temperate latitudes. The lowest
pressure is in d the isobars, as shown in.
imatic charts, are close together, Depresions vary
from 150 to 2.000 miles in extent. They remain
quite stationary or move several hundred. miles in
à day. The approach of a cyclone is characterised
bya fallin baromerri reading, dull sky, oppressive
sir and strong winds. Rain or snow falls and th
eather is generally bad. Winds blow inwards in

regions of low pressure in
anticlockwise direction in
and clockwise in the southern hemisphere (Fig. 1198).

he northern hemisphere

(Chaos caused by a typhoon in Hong Kong Government
Information Services Hang Kong

Fig. 119 (a) A cyclone in the northern hemisphere
(close sobars, an-lockwiso winds)
hemisphere (well-spaced isobars, winds
blow i clockwise direction)

Precipitation resulting from cyclonic activities is
ue to the convergence of warm tropical air and cold
polar sir. Fronts are developed and condensation
takes place, forming either rin, sow or sleet.
Anteyclones. These are the opposite of cyclones,
‘with Hh pressure in the centre and the isobar far
apart, The pressure gradient is gentle and winds are
light. Anticyclones normally herald. fine weather.
¡Skies are clea, the air is calm and temperatures are
high in summer but cold in winter. In winter intense
‘cooling of the lower atmosphere may result in thick
fogs. Antcyelonic conditions may last for days or
weeks and then fade out quiet: Winds in anti
‘yelones blow outwards and are also subject to des
fection, but they blow clockwise in the northern
hemisphere and anticlockwise in the southern hemi
sphere (Fig. 1199).

Climatic Types and Natural Vegetation
I is necessary 10 divide the world into several
climatic zones each with its own climatic character
istics, natural vegetation (forests, grasslands or
desert), crops, animals and human activities
"Though the geographical characteristics may not be
absolutely uniform in each climate type, they have
many things in common. Fig. 120 gives the scheme
ff the ord’ climatic types with their seasonal
‘ainfll and natural vegetation.

us

WORLD CLIMATIC TYPES:

‘imate Zone Lttude Climate Te ana Reime
2 loi) (With pren. a)

Natural Vegetation

Zone Ones 1.Hot wet gusto. Pattaya austria in oes
a ‘ound: 60 incor
“Hot Zone Nes A) Tope ese: Monon toms
(Tones! Mich summer ran
ae Taches
So un many in summer Savanne (ropa!
nes Feen
4 Dana jene: Le Desor veoetaton and
opera Since en
ease ype

‘Worm Temperate Zone 30-45 N.andS. 5 Western Margin Winter ain: 35 inchos Mediterranean forests
(Meataronean aran

E]
{6.ContalConinan- Ligh summer an:
E 2Dinces reia

Stppa tempera

Eu Margi: Heavier summar ain: Wm wet frets and
(a) Chnatype ne bamboo
(6) Gurnpe
es (al Nay
Co TemgraezZone — 45-E5NandS. 8 Westem Marin More raininautumn _Oecidious forests,
Br gpe) and wie: inches
5 Central Corünen. _Ughtsimmerran: Evergreen confrous
ta (Sbaran type) 2öincher forte
10. Eastern Margin Moderate summorrim Mixed forests (on

(aurentin type) aDinches foros ond decsuous)
O-S0N ends. 11.AreieorPolr Verylightsummerrin: Tundra mosses,
10 nens chers
12 Mountain cute Heavy afl ort) _ Apne pastures, con
fers form on.

Fa 120 Seon cf wants
clima types |
Seton lang
aural vegetation

Indien)

y

4. Distinguish the différences between
(a) troposphere and stratosphere
(0) steady Trade Winds and variable
Wester
(©) insolation and radiation
(@) tornado and hurricane

QUESTIONS AND EXERCISES

1. There are many ways in which rain may be
caused. Name any three of them and with the
aid of annotated diagrams, describe how each
of them occurs

2 Aten the role played by tem
pra dm ke vos g
tor that ac the distribution of temper 5
‘ature in the world? =

Explain any three of the following sta
(a) Antieyelones are more frequent in summer.
(9) Without water vapour and dust in
the atmosphere, there would be no
weiter
(©) Sletis frozen ran,
(@) Temperature decreases with increasing altitude.
(© Winds in the northern. hemisphere
are always deleted to thee right,

3, Account or the occurrence of any thre of
the following. Make use of any relevant
sketches.

(2) the planetary winds

(0) land and sea breezes

(©) frontal rain

(@) extremes of temperature in continental

(6) Horse Latitudes

SELECTED QUESTIONS FROM CAMBRIDGE OVERSEAS SCHOOL CERTIFICATE PAPERS
BÍO lt o Ju pe
{Td and od máxima and minima temps la choo eater tn,
1, clots peta epee fra pric saa
(0) Desert and sun fori temor anon agree
col pee ee eee
À. pla or Gus types cnt eligi bythe lus ea blow:
as
à Val de Te High
(oN ow) En Fa TC) tn EUS)
Lie
CBR ew) ir Ann TE QC) MITOS
a yat wd See rc WE cea cto te
D aio e a atin oe
ho
do Exp clay vas wich he schoo cn ae oc eo (1963)
3. Nite fun Spel ita wis bait again how dey Bow ea
ES
O entre i ai pcs nt peg
thine sted tcl th man sn tl (92)
4, veras fr he lowing a
Ea perl neath Coin cn
atten ote er rela ir wet sot content line baron PN eset
Len 208 and 0. | ñ
do arts Anc ae cla surco tesi cas Alan 196)
5. mene andrea espe eb sl Della od sa arty
Dow eat ofthe ess oe eal
(lind anda eu

=) (1968)

us

— i —

‘Chapter 15 The Hot, Wet Equatorial Climate

Distribution
“The equatorial, bot, wet climate is found between
Sand 10° north and south ofthe equator. Is greatest
“extent found inthe lowlands of the Amazon. the
(Congo, Malaya and the East Indes Further
“vay from the equator, the influence of the on-shore
Trade Winds, ges rise 1 a modified type of equato-
val climate with monsoonal influences. Within
‘the tropics, the equatorial highlands have a distin
tively. cooler climate, modified by altitude such as
the Cameron Highlands in Malaysia, the Northern
‘Andes and the Keman Highlands in East Africa,
Fig. 121 shows the regions of the world which expe
‘ence the ot, wet equatorial climate

Climate

"Temperature. The most oustanding feature of
‘the equatorial climate is its great uniformity of
emperatare throughout the year. The mean
‘monthly temperatures are always around 80°F
‘with very litle satiation. There is no winter.
lotes and hess precipitation help to moderate
‘the daily temperature, so that even atthe equator
"sl, the climate is not unbearable. In addition,

fig. 122 (a) Equatorial Cimete—a lowland sat

fi. 122 (5) Equatorial Cimate—a highland station
Fitude: e720fet
Anna temperature range: PE 62-57)

E

tation. Precipitation is heavy, between 60
inches and 100 inches, and well distributed through:
tt the year. There is no month without rain, and
A distinct dry season like those of the Savanna or the

eal Monsoon Climates, is absent. Instead,
e are two periods of maximum rainfall, in April
And October as shown in Fig. 122 (a) and 122 (0),

i Doce T
an. Ketan fr
m the North-East Mon:

he 3 Rangoon, Burma, from the South-We

Monsoon between June and September. AS 0
Turther north and sout ‘equator, part
with the fall coming in th
+ months, Le. June, July and August in th

thern hemisphere and December, January a
Due to heat in the equatorial bel,
dd sunny: There is mue

nder and

ning often accompany the 4
nount of rainfall recorded in one sing
fernoon may be as much as the deserts receive for
Ihe entire year! Besides the comectional rainfall
mor ns also experience much OrOgra
addition, there are some

Ionie atmospheric dis
ofa currents

ntermittent showers from

turbances caused by the conver
Doldrums

e ative humidity is constantly high (over 80

Forested slopes of Mt. Kinabalu. The lower slopes have
been clearedinplacesfor cultivation. Thevegetation on
thehigherslopesgraduslychangestnresponsetolower
temperatures Paul Popper

um

Per cent) making one feel sticky” and uncomfortable.
‘The monotonous climate, oppres and enervatn
faxes one mental alertness and physical capability
though along the casts cs do
bring some rei As a result, most of the whi
Seiler, whose bodies are attuned to cooler and
‘more varied condition take tothe cooler highlands
whenever they cam,

Equatorial Vegetation
High temperature and abundant rainfall in the
‘equatorial regions support a luxuriant ype of
oe tapia! In the Amazon
Towlands the forests so dense and so compete in its
vegeaional extanagance that a special term
is used. Unlike the temperate regions the growing
Season her is all the year round ceding, fowerin
Fri and decaying do not take place ina seasonal
Pater, so some tres may be in ower while others
on a few yards sway may be bearing fruit. There
iS nether drought nor cold to check growth in any
part of the year, The characteristic features of the
‘guatrialyegstation may be summarized as follows
1. A great variety of vegetation. The equatorial
vegtation comprises a mulitude of exergren tre
that yield tropical hardwood, eg. mahogany, cbony
renlicart, cabinet woods and dyenvods There
‘re smaller palm ress, climbing plants ike the Panas
Or atan which may be hundreds of feet long and
pDÄy and paras plans that ive on other plant.
fhe tees grow a wide variety of ferns
‘orchids and lala.
2. A dite layer arrangement, From the ar, the

topical rin forest appears ike thick canopy of
broken only here ts crossed by large ers
for cultivation. All plants strugee up.

‚over 150 feet (Fig. 123). The nk pierog
so se the top
Thesm ath Form ver, and th
sound is rooted with ferns and herhaon plas
which can tolerate shade, Because the tres cat ot
most of the sunlight he undergrowth isnot dense
3. Multiple species. Unlike the temperate fort,
where only fe species occur ina particular an
the tres of the tropical rain forest are

‘of a single species Tt has been es
mated that in the Malaysian jungle as many as 20
species of tres may be found in an acre of fone
This has made commercial exploitation of tropa

timber a most dificult task. Many of e

tropical hardwoods do not float radi

and this makes haulage an expensive mater. I u
therefore not surprising that many tropical counties
. Many parts of the ving

tropical rain forest
lumbering or shifting culta
ings are abandoned, less luxur
cal

we been cleared cil
on. When th

in Malaysia, spring up. These are

araterzed by short trees and very dense under

rot In the costal areas and brackish swamps
sis thrive

Life and Development
in the Equatorial Regions
The equatorial nerally
Populated. In the foresis most primitive people
Tie as hunters and collectors and the more advanced
ones practise shifting c Food is so abun-
dant in such a habita that many people worry very
litle about the life of the next day. There are numer
‘us animal, birds and reptiles that can be hunted
10 serve the needs of the community. The ever
Slowing rivers and streams provide an inexhaustible
Supply of fish that the people spear or trap. From
the forest, they gather leaves, fruits, nuts and
(ther forest products. In the Amazon basin the
India tribes Collect wild rubber, in the Congo
the Pyzmis gather nuts and in the jungles of Mal
the Orang Asi make all sons of cane products and
fall them 10 people in villages and towns. In the
stings for shifting culivaton, crops lke mani
). yam, maize, bananas and groundauts
due Brown, When the fertility is exhausted, tHe
‘faring is abandoned and they move on 10 a new
Blot. Such farming practice are becoming more and

‘more widespread even among backward tribes

Harvesting il palm fruits in Malays

have been established, especially in Java,
Sumatra, Malaysia, West Africa and Central America,
The climate has proved to be very favourable for the

distal: Wet. The most oustnding 5
callo" hen rani Thöngh
1 oter parts of the oquatr lands and gown
‘ery proiably on large estates Malaya and
Indonesia are Ihe kading producers ech ancountng
{more than atid of the worl! production. The
ome country, Brazil exports practical no ata
fur The problems of ee dieses and the
'ck of commercial organization ofthe Indias in the
Amazon lovlands have brought about ths une
Peed AH of rubber elation.

Another wopkal cop. that has achived an
Amazing success is cocos. It is most extensively
Alla in West Africa, bordering the Gull of

ins. The wo most impor! produce ae
‘Ghana and Nigeria. Thee i hen demand forthe
SPD and acreage are rapidly onthe inc. Mos
SF the cop lees West Ala for Europe or North

America for the cocos and chocolate industry
From the same area another crop, off palm, has done
equal well and many countries outside Africa have
jo taken to its cultivation, Other erops that have
been found suitable for the hot, wet equatorial

sugar, coffe, tea, tobacco, spies, cinchons, bananas,

Factors Affecting the Development
of Equatorial Regions
1. Equatorial climate and health. Under conditions
of Man is subject
vo. and mental handicaps. He
Perspires profusely and loses vigour and energy in
such an enervating environment. He exposes hime
self to such dangers as sun-stroke and to such diseases
aria and yellow-fever, Consequently, his cr
city for active work is greatly reduced and his
resistance to diseases is much weakened. Unless
there is adequate provision for sitisfactory sa
tion, physical and mental health are bound to be
affected, ‘Nowadays malaria eradication schemes
are in progress in most tropical areas and vaccnes

lzonointensivefamingtosupplyety-dwelirs
With vegetables is proftable Primary Production,
Department Singapore

no

shape to counteract other diseases
re and insect pests. The ho.
which stimulates rapid plant growth,
the pend of imss and pt As
a are more casi) warm
condoms ar es for
of such organisms. Insects and pests
ee but ae injurious fo ps
St mena animal
ocio nd maintenance.
“sara that tis quie a problem
itch of

d it and even more
it, Lang all gras) and thick
up as soon as the shade tees

are weeded at regalar intervals,

Livestock farming is greatly handicapped by
absence of meadow grass, even on the highlands
‘The few animals like bullocks or bulles are Kepa
mainly as beasts of burden. Their yield in milk or
beet wel below those of the cattle inthe temperate
grsslands The grass is so tall and coarse tht iti
fot nutritious, In Africa, domesticated animals
bitacked by weise flies that cause ngana, a deadly
disease,

QUESTIONS AND EXERCISES
or Sar
ger
20

0

x

=|
>|
=|
|
el

lo

8% inches
E

(a) Name the type of climate experienced
inesch ofthe stations
(6) Describe the major differences inten

perature and precip

(©) In what ways are the rainfall of the
the two stations similar

2. What typeof climate is characterized by two
periods of maximum rainfall? Explain why

this is so. What local conditions, may upset
this normal pattern?

3, Outline the characterises of
al climate and ve

fquatorial region describe how the inbabitant
fvereome some of the difficulties posed by the

equate:
on and for any one

4. Write bref notes on any three of the

following statements about the equatorial re-

(a) Cloudiness and heavy precipitation

moderate the temperature of the equatorial

() The most prominent feature of the
tropical rainforest its layer ara

(9) Largescalo livestock far
known in the hot, wet equator

(4) The le drawback 10 com-
ul Im
inaccessibility

(© The equatorial environment is best
suited to plantation agriculture

5. On the map of the world, locate the hot,
‘wet equatorial forests. Relate their vegets-
ional characteristics 10 the climate of the

regions

Tropical Monsoon
ropical Marine Climates

at the Tropic of Cancer the great land masses of
the norte hemisphere are heated. Central Av,
backed by the lofty Himalayan ranges, is more than
ASF halter than is normal temperature and a
region of intense low pressure is set up. The se

Which warm up much slower, remain comparatively
fool. At the same time, the southern hemisphere 2
experiences winte and a region of high pressure | Fg 125 (0) Summer conditions m An Sou dre a

fs set up in the continental interior of Australia West Monsoon in Indo-Palsten is Wise Sat ee
"Winds blow outwards as the South-East Monsoon, ‘onshore In. the rainy season Jub) Inthe cool, dry season (January)
o Jina, and after crossing the equator are drayn (Fig. 125 (b)). In other parts of the world which rain anywhere. By May, the temperature is 0

towards the continental low pressure area reaching experience a tropical monsoon climate à similar high that an intense low pressure zone is set up in
the Indian sub-continent as the South-West seasonal reversal of wind directions occur. northovest India. Duststorms are frequent, followed
‘Monsoon, as shown in Fig. 125(a). by long awaited rainstorms that “break” by the

The Seasons of Tropical Monsoon Climate middle of June. The transitional period between

In the winter, conditions are reversed. The sun

la oteiead at the Tropic of Capricorn. cour In eons ike the Indian subcontinent which have no ran and plenty of
Ths cena cold routine th tpl coving 3 tue Tropical Monsoon Climate, thee dint 3. The rainy season (niJane o September). With
Gf de lin. A egin of mp cae SO ar diga, es M in Fig. he hao he Sout Momo man,
ith oubloning winds-the North-East Monsoon @ total downpours esp across the country
Fi blog minds Noria Mom The col dy soon (October to February. o e dig of corn Alan al the rl or
Oe ane ie cat the winds re rod Temperatures are los JOE in Bombay and only the ear ls within thi rin Season, Fr example
a à 2 hr SO°F. in Punjab, with heavy sinking air. Frosts in Bombay 19.9 inches are recorded in June, 24
‚in northern Australia as the North-West Monsoon | may occur at night in the colder north. The centre inches in July, 14.5 inches in August and a further
Of high pressure is over the Pur Outlowing 106 inches in September AS much as 95 per cent
dry winds the Norh-East Monsoon, bring tle of he annual rainfall à concentre within four
fr no rain to the Indian subominent. onthe This pattem of somesntasd hey ane
However a small amount of ran fll in Punjab aaa dec
from cyclonic sources and this is vital for the survival ler
of winter cereals Where the Nast Monsoon le
Hows over the Bay of Bengali acquires mostre E
and thus brings rain to the south-eastern tip of the >
Peninsula at This tine of the soar. For instance,
in Madras 80 inches of rin fill during October
and November, accounting for half is annual
‘infil
2 The hot dry season (March o milan). As
an be sen from Fig, 126) the temperature He

{all in summer is & characteristic feature of the
Tropical Monsoon Climate. The tor
Pours have an immediate impact on the I
erature They lower the temperature considera
‘The mean temperatur for Bombay is 86

north the drop is even
: Some of the windward
stations on the Himalayan foothills have very heavy
nf, though this is partly orographic. Cherru-
‘pun bas an average annual rafal of 425 inches and
{record of 905 inches in 1861

‘The Retreating Monsoon
The amount and frequency of rain decreases
towards the end of the rainy season. It retreats
aradually southwards afer mid-September until
it mes the continent altogether. The Punjab plains
hich receive the southowest monsoon cats ar the
fist to see the withdrawal of the monsoon. The
skies are clear again and the coo, dry season returns
in October, wth the outblowing North-Fsst Mon

The role of monsoons in India is vital in ts cco-
nou. A late monsoon or one that ends far wo
‘arly wil condemn large stretches of agricultural
land to drought. There will be widespread famine
fiom crop failure and thousands will perish, When
there is 100 much water from the rainy monsoons,
¿severe ods occu, destroying both crops and lives
and dirupting communications. In no part of the
word has the climate affected Mans way of life so

D Due

‘The Tropical Marine Climate
This type of climate is experienced along the
Sous of tropical lands, receiving steady
‘rainfall from the Trade Winds all the time. The
rail is both orographic where the most trades
mes upland masses as in eastern Brazil, and conve
‘tional due to intense heating during the day and in
Summer. Its tendeney is towards a summer maxi
mu asin monsoon lands but without any distinct
ay period. Fig. 126, shows the rhythm of climate
Cairns on the easter coast of

Queria the constant inlence of the

€ tropical. monsoons. lis wee
in January (158 inches), February
and April (12), which is
‘hemisphere. Approximately
rainfalls concentrated
hs. There is no month

Fig, 126 (b) Tropical marine Climate
Place: Cairns, Australia (17'S, 165, 42%)

without any m
typical of the tropica
RE in January and

‘of temperature is
latitudes with a maximum of
nimum of 70°F. in July

a range of 12°F. for the year. Due to the steady
influence of the trades, the Tropical Marine Climate
is more favourable for habitation, but i is prone to
severe topical eyelones, hurricanes or typhoons, as
mentioned in Chapter 13,
Tropical Monsoon Forests
‘The natural vegetation of tropical
lands depends on the amount of the summer rail
‘Trees are normally deciduous, because of the marked
dry period, during which they shed their leaves to
‘withstand the drought, Where the rainfall is he
es in southern Burma, peninsular India, northern
Australia and coastal regions with a tropical marine
climate, the resultant vegetation is forest, The forests
are more open and less luxuriant than the equatorial
jungle and there are far fewer species Most of the
forest yield valuable timber, and are prized for thet
‘urable hardwood. Amongst these teak isthe best
known. Burma alone accounts for as much as thre
quarters of the world’s production. It is such à
durable timber that it is extensively used for ship
building, furniture and other constructional purposes
‘Other Kinds of timber include sal, acacia and some
varieties of eucalyptus in northern Australia. To
gether with the forests are bamboo thickets which
‘often grow to great heights (Fig. 127).

With a decrease in rainfall in summer, the forests
‘hin out into thorny scrubland or savanna with

Fig. 127 Main features of monsoon forest

scattered trees and tall grass In pars of the Indian
sub-continent, rainfall is so deficient that semi
desert conditions are found. Monsoonal Vegetation
is thus most varied, ranging from forests to thickets,
and from s serubland,

Agricultural Development
‘the Monsoon Lands

Much of the monsoon forest has been cleared for
agriculture to support the very dense population
The cultural landscape throughout the length and
breadth of the monsoon lands deeply reflets the
intensity of Mans quest for subsistence. Wherever
grown, The plains are ploughed
and the hills are terraced to provide farmland,
Farms are small and the people are forever “land
hhungrs’ In their quest for land, they, have removed
the natura. vegetation, sometimes wantonl, re-
sulting in acute soil erosion. This is particularly
Serious in the Indian sub-continent which has
& very high density of population with a
rapid rate of growth, But in the plains the
same piece of land may have been tilled for genera-
tions with little or no replenishment, and yet able
o yield Fury reasonable returns,

“Tropical agriculture dependent on natural rainfall
“and a large labour force reaches its greatest magn
tude in the monsoon lands. The soil provides the
basis for the livelihood of millions Farming is not
‘only the dominant occupation of the greater part of
the people, but also forms the mainstay of the eco-
nomy of the Indian sub-continent, China, South-
Fast Asia, easter Brazil and the West Indies The
Following types of agriclture are recognisable
1. Wet padi cuthation. Rice i the most important
Saple crop and is gow in tropical lowlands wherever
the rain exceeds 70 inches I à perhaps the most
‘characteristic crop of the monsoon lands and

total areage far exceeds that of any other crop.
Infact, very few arcas outside the influence of the
‘monsoons ever take to the cultivation of pad
There ate two main vareis he wet pad, which ds
mainly grown on lowlands in flooded fields
or in teraced uplands, and the dry pal grown in
regions ol lower rainfall. A minimum of $0 inches
of rainfll is required during the growing season
Droughts and Moods ıhat are almost inseparable
from a monsoonal type of climate can be very
detrimental 10 its culation, Iigtion water from
rivers canals dams or wells is extensively used
in the major ree producing countries. Other food
crops like maize, millet, sorghum, whest, gram and.
beans are of subsidiary importance. They are cul
‘ated inthe drier or cooler areas where rice cannot
be grown,

2. Lowland cash crops. A wide range of lowland:
tropical cash crops are eulthated for the export
market, after local needs have been met. The most
important crop in this category is cane Sugar. AS
much as wo-hirds of worlds sugar production
comes from topical countries. Sugar is either
town on plantations or on small holdings Wherever
Fainfall and sunshine are abundant. Some of the
major producers include India, Java, Formosa, Cuba,
Jamaica, Trinidad and Barbados. Jute is confined

Harvesting sugarcanein Queensland, Australia Austral
‘News and Information Bureau

almost entirely to the Ganges - Brahimaputra dela,

in India and Bangladesh. It has long been a
leading hard fibre for the manufacture of sacks
(guns). N (abaca) is a product of th

Philippines, particularly of Mindanao. It is used
10 make high quality rope Other crops include
indigo, sil clivated in India and Java a
major esport of the Indian sub-continent and
Bananas, coconuts and spices.

3. Highland plantation crops. The colonization of
Tropical lands by Europeans gave rise to a new form
‘of cultivated landscape in the cooler monsoonal
highlands This is the cultivation of certain tee
crops in topical plantations Thousands of acres
of topical upland forests were cleared to make way
for plantation agriculture in which tea and coffee
are the most important erops These were luxuries
in Europe in the eighteenth century and the products
‘of the plantations were originally meant only for
‘export to the mother countries where there was a
Beat craze for the beverages Later, the local
People also got into the habi of drinking them and
they fast became necessities. Both the beverages
became so popular in and ou of the tropics that there

“Tea picking na plantation in Si Lanka Camera Pres

was great expansion in their ac:
with a Tropical Monsoon Clin
Marine Climate.

originated in Eihiopi
its sill grown, but Brazil n
half the world’s production of
grown on the

opes ofthe
“The crop is also cultivated on the highlands

between 2.00 feet and 4,500 feet in the Coma
American states, India and aster Ja

‘originated in China and is still an important
crop there, but as it requires moderate :
(about 60°F), heavy rainfall (over 60 inches) and
weil drtined highland slopes it thrives well in the
tropical monsoon zone, but preferably at
higher altude. The best regions are thus the
Himalayan foothills of India and Bangladesh, the

central highlands of Sri Lanka and western Java
from all of which it is exported.

grown mos fr local eonsumptio
4. Lumbering. Wherever there are tropical forests
hich still have not been felled to make way for the
plough, lumbering is undertaken in the more acess
ble areas. This is particularly important

In China tea is

sin River the Te take
that they will not oat readily on water. Its
actual fling, so that it is ht enough
floated down the Chindwin and the Irrawaddy «
reach the saw mills at Rangoon. The individual
Togs are tied in rats and guided downstream b
crews of men and tugboats It takes something lke
18 months for a log of teak to reach Rangoon to b
Sawn into planks for export

5. Shilting Cultivation, This most primitive form

of farming is widely practised. Instead of rotating
crops in the same field to presene fertility I
tribesmen move to a new clearing when their frst
field is exhausted, The clearing, or fil, in the mi
ofthe jungle is usually made by fire, which destroys
practically everything in its way. After plan

u is paid to the field either in weed

or manuring. The erops are left entire to the care
Of nature. The farmers use simple
for ploughing and seeding. Draught animals are
unknown and labour is exclusively Their
needs are so basic that every farmer produces much
the same range of crops as his neighbours. Maize or
com, dry padi, yams, tapioca, sweet potatoes and
Some beans are the most common crops. Farmi
is entirely for
bythe farmer's family, it snot traded or sol
As tropical soils are mainly latosoic, rapidly
Jeached and easily exhausted, the fist crop may be
Dountiful but the subsequent harvests deteriorate
A few years late, th feld has to be abandoned and
a new patch cleared elsewhere. This system of a
short period of cultivation alternating. with long
periods of fllowing is probably the best way of using
Hand in many pars of the topics where manuring is
unknown,
‘Shifting caltivation isso widely practised amongst
indigenous peoples that different local names are

i, everything i cons

QUESTIONS AND EXERCISES

(6) The Tropical Monsoon Climate is in
fact and and sa breezes on continental
sale

(9 Near the equatorial latitudes, the pe
104 of maximum rainfall is closely

(4) There is a marked difference in tem-
ure between the east and west
of countries in latitudes

3. Inwhich parts ofthe monsoon lands has the
natural vegetation been removed by men?
Deseribe and explain the uses made of the
cleared lands

4. Name the types of climate which have
(2), rain mainly in winter
(6) rain onlyin summer
(©) min throughout the year
iL Describethe characteristic climatic
features of any two of the types
sou have named.
ji, For any one of them account for
its rain distribution.

5. Contrast the essential characteristics of
plantation agriculture and shifting cultivation,

17

Bese
“Ths Savanna or Sudan Climate & a wansionl
eof climate found between the equatorial forests

athe rad wind ho deserts Its confined within
ad x best developed in the Sudan where

nd wet seasons are mos distinct, hence its

Chapter 17 The Savanna or Sudan Climate

The rest of the year is cool and dry. The

rafal for Kano, wich is located ata height of 1599
fet above sn ec, is 4 inches andi almost ot
concert inthe summer. But the amount varie
from 48 inches at Bathurst, in Gambia on the coast
Ko nb inches at Khartoum, in Sudan in the menor
Both the length of the rainy season and the annual
total aif decrease appreciably from the equatorial
segon poleward tonands the deser fringes On the
‘Whole te annua preiitation is es han hat ofthe
Tropical Monsoon Climate and the length ofthe wet
and dry seasons dir withthe locali Inthe
Souther hemisphere, the rainy season i fon October
{o March the southern summer) as shown in Fig
1290) of Salsbury, in Rhodes. Its annual pre
pilation of 32 ins alo varies much fom year
to year. i

"Temperature, The monthly temperature hovers be
tween TOF and 90°F for lowland stations. An
annual temperature range of 20°F (pi, ut
therangeinceassasone moves further a om the
equator is, however, interesting to note thatthe

iL

Fig. 129 (a) The Sevanna or Sudan Climate in the
northern hemisphere

Place: Kano, Nigeria (11° SEN.

Aude: 1,839 fet

Annual precipitation: 34 inches

‘Annual temperature rango: 17 (68-72)

— ho

© we)

bi The Savanna or Sudan Cimate in the
Southern hemisphere
ce Salar Modas (17455, 91)

Aldo: 4,4981
Annual precipitan: 92 inches
‘Annual temperatur range: 15'F01-561

| highest temperatures do not coincide with the period

ingest un (ce. Dune nthe tbr emi
ln the en ot ie mi

Days are hot, and during the hot season, moon
temperatures of over 100’E, are quite frequent
When night falls the clear sky which promotes
intense heating during the day also causes raph

radiation in the night. Temperatures drop to well
below SO'E and night frosts are not uncommon at
this time of the year. This extreme diurmal range of |
temperature is another characteristic feature of the
Sudan type of climate.

Winds, The prevailing winds of the region are the
Trade Winds which bring rain t the coastal districts
They are strongest in the summer but are relatively
dry by the time they reach the continental interiors
fof the western eoasts of the continents, so that grass
and scatered short tres predominate. In West
‘Africa, the North-East Trades in fact, blow offshore
from the Sahara Desert and reach the Guinea coast
as a dry, dustladen wind, called locally the Has
fmattan, meaning ‘the doctor. Iti so dry that is
sine humidity seldom exceeds 30 per cent. "The
doctor provides a welcome reli from the damp air
‘of the Guinea lands by increasing the rate of evapora:
tion wit resultant cooling eects, but tis such a dry
dusty wind that, besides ruining the erops it also
Stirs up a thick dusty haze and impedes inland river
navigation.

Natural Vegetation
‘The savanna landscape is typified by tall eras
and short tices Tt rather misleading to call the
Savanna ‘tropical grassland, because trees are always
present with the luxuriant tall grass The terms
‘parkland’ or “buheveld’ perhaps deseibe the lande
ape beter Trees grow best towards the equatorial
humid latitudes or along river banks but decease
in height and density aay from the equator (Fig. 130)-
‘They occur in clumps or as scattered individuals The
trees are deciduous, shedding their leaves in the cool,
{ey season to prevent excessive loss of water through
transpiraion, eg. acacas. Others have broad trunks,
with waterstoring devices 10 survive through the
prolonged drought such as baobebs and boe tees
‘Trees are mostly hard, gnarled and thoray and may.
‘exude gum lke gum arabic. Many trees are umbrella
‘Shaped. exposing only a narrow edge to the strong
‘winds, Palms which cannot withstand the drought
Are confined to, the wettest areas or along rivers.
Vegetative luxuriane reaches is peak in the rainy:
is!

nie anna and the
growing 6 to 12 1
aan or en on Te

i Be

!

yy

yyy yyy
LLL, dA,
Fig. 130 Changes in vegetation from Savanna to desert

grow in compact mis and has long roots which
reach down in search of water. It appears greenish
and well nourished in the rainy season but ums
yellow and dies down in the dry season that follows
‘The grass les dormant throughout the long, rinlss
‘Period and springs up again in the next rain season
In between the tall grass are satire short trees and
How bushes. As the rainfall diminishes towards the
déserts the savanna merges into thorny scrub, In
ale i eri palo el rep
‘sented by a numberof species: mallee x

de mula pie

Wi)

Sens conga

III
777777
MI

NN

that many of the animal films that we see at the cinema
are actually taken inthe savanna,

There ar, in fact, two main groups of animals in
the savanna, the grass-ating herbivorous animals and
the feshing-eating carnivorous animals. The herbi
vorous animals are often very alert and move swiftly
from place to place in search of green pastures They
‘are endowed with great speed to run away from the
sage flsheters that are always after them. The
leaf and grasscating animals include the zebra.
antelope, giraffe, dee, gazelle, elephant and oki.
Many are well camouflage species and thir presence
‘amongst the tall gresnish-brown grass cannot be
easily detected. The giraffe with such a long neck
an locate its enemies a great distance away, while
the elephant is so huge and strong that few animals
‘will venture to come near it, It is well equipped
‘with tusks and trunk for defence

‘The carivorous animals like the ion, tise
‘eopard, hyaena, panther, jaguar, jackal, Iynx and
puma have powerful jaws and teeth for attacking
‘ther animals Their natural colourings of light

in many paris of East and South Africa
Kiling of animals This is necesi, if many ofthe
protected from wanton Shooting In Kenya ther
to bring tourist o sec the animal in tir natural
raged

Human Life in the Savanna
Within the savanna lands of the tropics live many
different tribes who are ether eat pastoralists like
the Masai of the East African plateau or settled
caltivators tke the Hausa of northern Nigeria, We
hall examine the life of these two groups of people
more closely and see how they adapt themselves to the
‘The Masai, cattle pastoraliss, The Masai are a
nomadie teibe who once wandered with their herds
‘of cattle in the central highlands of East Africa
in Kenya, Tanzania and Uganda. At the height of
their power, in the mid-nineteenth century the
numbered about $0,000. But today after a century’
tribal clashes, epidemics and natural death, their
numbers have been greatly reduced. They are now
‘mainly confined to the 15,000 square miles of Masai
reserves in Kenya and Tanzania. Their old grazing
grounds in the Kenyan Highlands were taken over
first by the immigrant white settlers for plantation
agriculture (oler, tea, cotton) and dairy farming and
later, after independence, by African farmers. They
now oocupy the Jess fivoured areas of sama.
‘which are grazed something ikea million cattle and
perhaps twice as many sheep and goats. On the lower
‘Slopes of the East African plateau, where rainfall is
low as 20 inches and there are long periods of drou,
| the asseldom eche foo high and snot mat

ASS

The cat are the sebo cate
with humps and long horns They 04 with
rest repost and action and are never slaughtered
for food or fr sal. The bee is only consumed when
they die a natural death from or disease

They are never used as draught animals and are Kept
entire forthe supply ol Milking
is done by women before day-break and at

The yields extremely low by any standard and usually
not more than two pints are obtained at a single
milking. The milk is drunk either fresh or sour
Chessemaking is sil not known to the Masa
Blood from both bulls and cows is drunk. This is

obtained by tying a leather cord around the neck
of an animal until the seins sell A vein i then
punctured by a special arow-head and the blood
uses out and is collected and drunk fresh or lotte

Cattle are kept by every Masai family. They are

dere far more valuable than anything else and
are th, The richest man has the
largest herds of cattle, leaving aside the sheep and
oats which, to the Masi tribes, are of litle signi
fence. Cattle are used in payment for wives, and
‘when the Father of a family dies, the mother divides
the livestock among the sons. The Masai will not
slaughter the cattle for foo, o from the agricultural
i tribesmen drink the blood aswell asthe milk
mato but do not Kl them for meat Camera

Bi

‘The Hausa sow the seeds in late April when sufficient
rain has fallen. The seedings sprout with the han
fain and grow rapidly throughout the rainy season,
Weeding with traditional hoes is done at regular
intervals ul the crops are ripened and harvested
in September, the beginning of the cool, dry season,
‘The tll brown bushes are burnt down by the farmers
in prepartion for new fields for the following year
Sometimes fres may be caused by the dry, dusty
Harmatın.

ee nennen:
ll amount of mile, bananas, groundauts and
mme
de Le ‘their quality, the Masai will

ingly sel thei ct. SO he large area of
hey occupy in East Affi 5 not ud
‘Great cos are being made to tthe

Problems, Prospects and Development
of the Savanna
here ig Title doubt tht in years to coms, world
Population pressure and the need fr greater ood
production wll neestate greater economic develop.
matt ofthe savanna, The deserts or the frein
und form climate barriers too formidable or
large sale human intervention 10 take place, But
the savanna lands ith an annual rl of ver
Winches nd without any severe cold, shouldbe ale
{o support a wide range of topical crops Poner
sement in ental Alia, northern Assia
and easter Brazil have shown that the savannas have
immense agriulural potential for planation ag
tre of cotton, cane sugar coffee o palm, round
ut and eten tropical fruits Tropical Queensland,
despite is sar of labour free has been er)
successful in its attempts to develop its huge cnpıy
land. The newly independent ses of Ken,
Uganda, Tanzania and Malawi have already taken
to largescale production of coton and sia hemp.
Both crops thrive well in snanna conditions. In
West Africa, the commercial cultivation of ground:
ut, oll prim and cocoa have been gradually ex
ended into the swanna lands. New droughtsesi-
“tant varieties will have to be introduced into these
“newly emergent countries to increase their foreign
amis in such tropical raw materials In ie
highlands, temperate crops have eon suce

in the savanna land is not without
Droughis may be long and tying.
a unreliable. Unless count
adequate

Techniques. but the majority. stubbornly
in their old ways. Amongst most of the
can tribes, pastoralism exists side by side

fie :
hate who inhabit the anna

of the Bach Patent. of norbem Nigeria.

y number almost sx millon and have Do
ze “settled agricultural communities for

gays of life than many of the other
€ in towns or villages. The ancient

sith a population of 135,000
of routes and trade. They do

Whe plant mine such astra pho
pot ae dise and washed ery Dur te
mest of the Wate. Many sarnna areas Url
He por ho naa of
Roser though reir mantra. weine an
Carla mainenans cop ide rebound lo
deste

Se pastoral Cate are Kept in large mies and
fed onthe al gas or de babe They prole
the people with milk, blood and meat Unis
Oe made o cat re Dany ds VM lia
Tat or mike They often all ea 1, Logia)
denses, eg. Ihe nana or sine sacs ated
by de teu yin Ain The expo of eer bet
fF milk fom the topical grans 50 far not
porn.

Ht som necessary to introduce temper ste
such as ie Ena Shortor, Fran or Gemey
{0 cross Wh the opel seh clio So
te src inthe savanna, In a, a sat has
tired, teca mate in sopla Que Wek
Jas bone Austral last cate prod
Site Both meat and mik ae sorte. In aba
Bons such at the compas ond los of South
‘Ame, hough cate ranching as ben cmd out
for centri, ite progres bas been made 0 fi
The gully of the gras nods 10 be improved and
à beter network of communications i cent.
‘Above ete Breslin and ase ono mst De
Card out on à eile basic In Ihe can
Sarena, te ate of sich mtv heran athe
Mas who trat ae as preige animals not
for slaughtering, wil pose many dices van.
the sommer of the eat dis Buts
2 apical eon, the sein. olde get
promi for aa.

QUESTIONS AND EXERCISES

1. The following are brief description of three
diferen ypes of climate
(a) A very large temperature range, with
(D) Distinct wet and dry seasons. with
concentrated summer rain
(9) High uniform temperature with well
distributed heavy rainfall
i. Name te type of climate
fi, For any ovo of them, give a fuller
description of the climate and the
factors which give seo

2. Explain why
(@) The saanna lands have a parkland
{ype of natural vegetation
(0) The svanna is the natural home of
cattle
(©) The savanna grass decreases in height
and lusuriance further away from the
equator
(4) Rainfall in the Sudan Climate is con
centrate inthe summer,

3. Write a descriptive account of
Either: The Masai, pastoralists of East
Alia,
Or: The Hausa, food growers of north
em Nigeria
‘You should bear in mind the environmental
influence on their mode of ving

4, Tis sad thatthe swam land hols great
promise for the future, Do you think so?
Why? Outline some of the probable di“
culties that may be encountered in their
development:

Chapter 18 The Hot Desert and Mid-Latitude Desert Climates

Distribution
Deserts are regios of scan nfl which may
Fe ot tke te ht deserts of the Saharan type: or
temperate as are the mate deserts Ike the
Gob. The arity of the hot desert à mainly due
16 the elit of offshore Trade Winds hence they
are ako called Trade Wind Deserts The temperate
deserts are anes baue of her interior location
in the temperat latitudes, well ana fom the rire
bearing winds,

“The major hot deserts of the world ae located on
the ester coasts of continents between latitudes
15° and SON. and Sas shown in Fig 11. They
include he Sahara Desert, the largest single set
of desert, which I 3200 miles from esto wet and
at east 100 mis wid. Ts tal area of 3.3 milion
Square mis i ager than al the 50 sates of USA.
Pat together. The next biggest desert is the Gral

lan Desert which covers almost Half of the
‘other hot dors ae the Arabian
Desert, Thar Dese, Kalahari and

Non Amer, the det

into USA and ca by

Sonoran, Califonian and Mexican Deserts In
South America, the Atacama or Peruvian Dese j
the driest of all deserts with less than 0.5 inches or
rainfall annually

‘Amongst the mid-latitude deserts, many are
found on plateaux and areata considerable distance
from the sea. These are the Gobi, Turkestan and
Patagonian Deserts The Patagonian Desert is more
due to its rain-shadow position on the leeward side
of thelofty Andes than to continental

Climate
Rainfall. Few desers whether hot or mid-latitude
ave an annual precipitation of more than 10 inches
For example Willem Creek in Australia has
54 inches Kotah in India has 4 inches
‘Yuma, Arizona, USA. has 33 inches. In Sala in the
mid-Sahara and Arica in the mid-Atacıma have
Practically no rain at all. In the later, Less than
‘002 inches fell within a period of 17 years in three
light showers! In another station less than 150
miles away at Iquique, not a single drop of rain was
recorded forfour years and then torrential down

feature of the desert climate
Weshull examine more closely why they are so dry

1 stride the Horse Latitudes or
the Sub-Tropical High Pressure Belts where the air
is descending, a co
precipitation of any Kind to take place. The rain
fearing Trade Winds and the Wester
es that are onshore Blow outside the desert limi.
Wher
10 warmer regions and ther relive humidity à
Jowered, making cond nos impos
There is scarely any cloud in the continuous blue
sky, The relative humidity is extremely low, de
creasing from 60 per cen in coastal districts 10 less
than 30 pr cent inthe desert interiors Under such
conditions, every bit of moisture i evporated and
the deserts are thus regions of permanent drought.

Precipitation is both scarce and most unreible
Coastal stations like Massawa on the Red Sea, as
ilusated in Fig. 1320) revive light seated
showers from the onshore winds, amounting 10
59 inches for the year. On the western coasts the
presence of cold currents (indicated by arows in
Fig 131) gives rise to mists and fogs by chiling the
‘oncoming air. This air is later warmed by contact
with the ot land, and litle rain falls The des
Seating effect of the cold Peruvian Current along
the Chilean coast is so pronounced thatthe mean
Annual rainfall for the Atacama Desert is not more
than half an inch! Rain normally occurs as violent
thunderstorms of the comectionl type I ‘bursts!
suddenly and pours continuously for a few hours
‘over small areas An inch or more may be recorded
in one single shower! The thunderstorm is so
violent, and comes so suddenly that it has disastrous
consequences on desert landforms
Temperatre. The deserts are some of the hotest
Spot on earth and have high temperatures throughout
the sear. There is mo cold season inthe hot deserts
and Me serge Summer temperature is round
86°F The highest shade temperature recorded is
TRO. om the 13 Sepenber N22 a Al Any 25
niles south of Tripoli, Libya, in the Sahara. Days
‘re unbearably hot, and in the open barren sands,
OYE is often recorded. The reasons for the high
temperatures are obvious—a clear, cloudless sky;
int insolation, ry a and aid it of por:

hot deserts ie

winds res

77 ww
des
at
4

ELCH i
T H 3
T

HET
HE

Pace: Massawo, Ethiopia (IGN, 39)
Alu: 64 fost

Annual precipitation: 59 inches

‘Annual temperature range: 1.7 (8878)

Fig. 192 (a) The Hot Desert Climate

PR
test

Pace: Keshga, China (ON. 76)
255 eat

4;
Annual precipitation: 35 inches
Annual temperature range: 8 (80-22)

Fig. 132 () The MidLatiude Desert Cimste

have much Tower temperatures eg. Arica has a
‘mean annual temperature of 66°F, Iquique 63°F,
Pal By Sa, A, only GR The

higher summer temperatures and the winter months
| are rather cold. For example In Salah, in the
Sabara, has a temperature of 99°F, in the hottest
month but only SSH in the coldest. month
‘The annual range is 44°F. The range for Yuma is
36°F. and for Jacobabad is 41°F. In comparison
the station Massava, illustrated in Fig. 132).
located near the coast, facing the Red Sea has only a
moderate range of 17°F Ils hotest month is July
(OST) and its coldest month is January (78°F),
‘The diurnal range of temperature in the deserts
is very great Intense insolation by day in a region
of diy air and no clouds causes the temperature to
rise with the sun. The barren ground isso intensely
heated that, by noon, particularly in summer a
reading of 120°F. is common, But as soon as the
Sun sets, the land loses eat very quickly by rds
and the mercury column in the thermometer drops
%0 well below the mean temperature A da
temperature range of 30° to 40°. is common, though
in the Death Valley of California, an exceptionally
great diurnal range of 74°F, has been recorded,
Frosis may occur a night in winter, These extremes
Of temperature make desert living most tying. Ths
‘explains why the desert people wear thick gowns all
(day long, to protect themselves from the glaring heat
by day and chiling frost by night, not to mention
e sand grains that are cari by the wind,
Climatic Conditions,
in the Mid-Latitude deserts
‘The climatic conditions of the mid-latitude deserts
“re in many ways similar to those of the hot deserts

the high mountains
they are cut of from the rinsbearing winds Oc.
Suionlly depresions may penetrate the Asia
ring light rainfall in winter

Storms may bless the

ais

Due 10 th
winter

Winters are often severe, freezing lakes and
and strong cold
Joe thaws in

slow all the time. When yy
ar summer, Noods occur in mar
places. The greatest inhibiting factors to stem,
Are the winter cold and the permanent ur
besides remoteness fom the ea

Desert Vegetation
All deserts have some form of such as
fra, serub, herbs, weeds, rots or bulbs. Th

they may not appear green and fresh all the un
they le in the sol awaiting rain which comes
at irregular intervals or once in many years Tie

environment, so lacking in moisture and so excess
in heat, is most unfavourable for plant
significant vegetation cannot be expe
very raely are there deserts where nothin

The predominant vegetation of both hot and
‘mid-latitude deserts is
Serub This includes the bulbous cacti thorny
bushes long-rooted wiry grasses and scattered dart
Acacias. Tres are rare except where there is abu
ground water to support clusters of
Along the western coastal desert washed by cold
‘currents as in the Atacama Desert, the mists and
fogs, formed by the chilling of warm sir over cold
urrens, roll inland and nourish a thin cover of
vegetation,

Plant that exist in deserts have highly specialized
‘means of adapting themselves to the arid environ
Intense evaporation increases the sity of the soil
50 that the dissolved salts tend to accumulate onthe
Surface forming hard pans Absence of moisture
retards the rate of decomposition and desert sols
fare very deficient in humus. Plants, whether annuals
perennials must strugle for survival agains both
aridity and poor sol

Most desert shrubs have long roots and are well
Spaced out to gather moisture, and search for ground
Water, Plants have few or no leaves and the foliage
is either wany, leathery, hairy or necdleshaped 10
reduce the loss of water through transpiration, Some
‘of them are entirely leafless, with pricks or thorns
Others like the cacti have thick succulent stems to
store up water for long droughts, There are sill
others that shed their leaves during droughts. The
seeds of many species of grasses and herbs have
thick, tough skins to protect them while they lie
‘dormant. They germinate at once when their seeds
are moistened by the next rain, In shor, all plants
must adapt themselves to survive in such an in-
hospitable region asthe desert,

Desert plants in Arizona

Life in the Deserts
Despite is inospaliy, the der hs ahays
been peopled by dierent groups of inhabitants
They Frage agas an emronment Sta In
a fd and ar mais of st, Sone
le the Eppuans hive allied a Ml Inc 0
lan, sis be the Bolouin Ab have
fed quite el nih their Docks of shee Boats
camels and horse The Bushmen of the Kahan
nd the Bid of Asta remain so priv
in hir mode of Tig that thy tre ae
They as infact io he OH Stone Agi the
modern wor. The dest inhabianıs may be
oupe us e loin ers. E
12 Te primi hair and easton. Of e pr

Wer

iio de ana a ie a
ing no suite The Damen mam te Kala
sert with their bows and poisoned arrows, spears,
a
En et armen oe
a
ey ne many nda 1 a bu tt
oe
eS ae eee
Ce a
A oe gua ead as Get |
men
in eu

ur

s is necessary 10 dig
m damp sand and suck the water up from the
a hollow reed, This is offen a very
‘Bushimen either wear a Join cloth or
naked. They travel in small family
live together in open sherms. This is 8
beneath a thom tree, surrounded by
frei it to keep the family warm.

(Or Aborigines of Australia ive in

‘same way as the Bushmen, They are

bt healthy, They are skilled trackers
them use wooden throwing sticks or
‘They also domesticate the

assists them in tracking down

‚Shell, Very often,

moles and insets, 10
the wandering Bushmen,
groups in search of fresh

But one distinct difference is that
10 a water supply as they sill
means of tapping and storing

in motes simple shelters made of

‘are scanty patches of pastures. wells or springs. 1
this manner, one group rarely clashes with the ei.
in ther search for new grounds to pitch their ua
Since they move so often, they always travel ight a's
only th esentials are carried along =
Eur cara tales These Wer the tray
merchants of the desert. Their journeys acrow ihe
‘wastes of the Sahara or Russian Turkestan sometimes
Tasted months or even years They trnelled at nom,
as a team and were well armed. They carried.
merhundie vas He sought ier Thee gc,
Mer ol or chanel for hides, rus campos ns
ber valuable products of the ders, Those
rls perohigh ei wereequly gr

The pacianimal ised by the cartas to cary
ther goods across the deserts was the came, a
Absa asthe “ship of the deer Unike ha
which hive sharp hoowes tht sink ready ine
Sandy desert, the camel has broad padded feet that
Wl not ap in the sind À pack ctl, algue
Te can cry a load of 350 pounds and temo
50 mies à day And a ring ste! ean do ine
the distance when ridden! The camel has seal
ter advantages provides milk and hal. I can
Sire up Water in is somach, and ft ins hun
$0 tha it can o for long penods without ihr

food or water.
ith the introduction of modern air, road and

ral trasporte oleo can trade res
teil Goods an be some much moe cap
eier security by desert jepa vans or
Mr But between the interior oases and sated
pts Bond the each of roads ca
routs remain the on form of aalabe transport
À The set anon For cop 1 esd
he desert, irigton i indispensable This is
obtained ihr rom oases rivers or dams, trough
A network of canals In Egypt, the Nile supports a
‘upton of 25 mon, many cren ne
Nike alley and dela, The giving waters of the
=k it possible for the Egyptians to raise
Tops as arly as ago. When the
‘Mie toons ily as 5,000 years ago, When th
“caught in basins
‘fields to irrigate

effective for extensive irrigation works. The flood:
Water can be held back and controlled and then
released at any part ofthe year to fed the fields that
yield two, three or even more crops a year. In the
same way, desert cultivators rely on the Indus in
Pakistan, the Tigris-Euphrates in Iraq, and the
Colorado in the Imperial Valley of California, and
are able to itrigate millions of acres of arid land for
op production,

Th the déserts, wherever there are oases, some
form of settled life is bound 10 follow. These are
depressions of varying sizes, where underground

water reaches the surface. Some of them are ab
normally large lke the Tafalet Oasis in Morocco
Which measures 5,000 square miles, supporting mi

Settlements, including large towns Others may be

So smal that they are no bigger tha

that we are so familiar with, eg. the Ghadames Oasis

of Libya is only one square mile in size. Life in an
anise, À wal is usually

sto keep out the violent

he mining pools

ass i secure and well
constructed around the o
dust storms called simoom The oasis people live
in mud-brick houses with Bat roofs, closely packed
together. The streets and winding
“and the heart of the settlement is dominated by the
Sq (central market place), the mosque, school and
shopping blocks. Sugs may also be set up miles
from anywhere and people come from a number of
surrounding settlements on special days to trade
‘Around the seulement are the agricultural lands
Water is led to the fields by irrigation channels or
ras up from wells by camels or mules. The most
important tos is the date palm which is grown in
<dug-out hollows so that is roots can penetrate deep
into the ground in search of water. The fruit is
consumed locally and also exported. Other crops
cultivated include maize, barley, wheat, coton, cane
sugar, fruits and vegetables With the development
of motor routes across the deserts, many sophisticated
foreign goods can now reach the uses.
5. The mining settlers. The lure of mineral wealth
has attracted many immigrants into the desert
Mining camps and isolated setlements have sprung
up following the discovery of certain mineral deposits
Ik was gold that brought immigrants scrambling into
the Great Australian Desert, Water and food
supplies have to be brought 300 miles from Perth to
‘keep the mines going. Some of them like Kalgoorlie
“and Coolgardi have become towns of considerable
‘siz In the Kalahari Desert, the discovery of
diamond and copper has brought many white men
0 the “stand” as itis called. Even in the most

‘The oo El Gale. The duns are gradual eneowehing
‘onthe date pals Camera Pres

arid Atacama, in northern Chile, large mining camps
have been established for the mining of calíche
(Cemented gravels) from which sodium nitrate, a
valuable fertilizer, is extracted and exported to all
parts of the world, The mines are worked by local
Indian Iabourers and supervised by foreign tech
nicians. Besides nitrates, copper is also mined
‘These two products have directly or indirectly con-
iribted tothe growing size of the Chilean towns of
Arica, Iquique, Antofagasta and Chuquicamata,
‘The last named is the world’s largest copper town,
Similarly in the desers of North America, slvr is
‘mined in Mexico, waniun in Utah and copper in
Nevada. A host of other minerals and their by-
products hive, in fact, greatly altered the landscape,
And the economy of such arid regions

Tn recent years the discovery of ol in many parts
of the Saharan and Arabian Deserts has transformed
this forgotten part of the globe. In Algeria, oi wells
have been sunk two miles deep to tap oil. Inthe
Middle East, pipelines over 1,000 miles Tong have
‘been lid o bring oil from the shores of the Persian
Gulf across Saudi Arabia to Saida (Lebanon) and
Banias (Syria) on the Mediterranean coast. With
il half of the world’s reserves of oil untapped in
this region, the deserts here will virtually be paved
with gold! In Iraq, Kuwait, and Saudi Arabia the
desert landscape is fast changing. New roads, huge
palaces, ultra-modern hospitals air-conditioned apar-
ments and swimming pools are examples of a thriving
new era created emirch by og gold

is aL

‘on the western coasts of continents

(6) Patagonia is a desert inthe rain shadow
of the Andes.

(©) The annual range of temperature is
müch rester at Kashgar (Gobi) than at
Iquique Atacama.

(@) Desert plants must adapt themselves to

(©) Camels are the ‘ships of the desert’

3 Waite brief notes on any dre ofthese tops,
(a) The Bindibu of the Great Aus
Desert

(b) Date palm cultivation in an oasis
(©) The role of oil in the development of
desert economy.
4) The Bedouin—the wandering herds.
© agria
ural development of any select
ed desert region.

Chapter 19 The Warm Temperate
Western Margin (Mediterranean)

Distribution
The Warm Temperate Western Margin Climate
i found in relatively few areas in the world, They
‘are entirely confined to the western portion of cont
ental masses, between 30° and 45° north and south
‘of the equator (Fig. |

) Ti bas ase of i
Of ciate the fing of the wind ie
plain in Chapter 13. Though the ars ao
the Meicracan Sex has he gets etn of th
more popular name Medicrancan Clim, the
Bes cele form of hs pora mate tp
lo fact, Band in coal Chie (ig 139. Dr
Melerancan regions include California ound
Sin Fran), the southwestem tp of Ale
{round Cape Town) southern Asal (in southern
Vitoria and around Adele, border he St
Niner and Spencer Gul) and some Asta
(Granta,

Climate
‘The Mediterranean type of climate is characterized
by very distinctive climatic features

Fig. 183 Regions wit a Mediterranean Climate

Climate

1. A dey warm summer with offshore trades. As
ilustrted in Fig. 15 (a) and (), he summer months
have relatively high temperature (76°F. in July in
Rome and 70°F in January in Cape Town) The
highest temperatures are however experienced further
away from the coast in the more continental exstem
Mediterranean, inthe interiors of the Balkan penin-
sul, the Anatolian Plateau and Mediterranean
Middle ast. For example, the July mean for
Athens is SOI, Larrissa (Greece) IE. and Beirut
(Lebanon) 83°F. Elsewhere in central Chile, South
Africa and Mediterranean Australia, due to their
‘coastal position, the influence of the sea has modified
the temperature and the January means (Southern
Summer) are normall around 70°F

In summer when th sun is overhead atthe Tropic
of Cancer, the belt of influence of the Weseris
is shifted litle polewards Rain bearing winds are
therefore not likely to reach the Mediterranean
lands. The prevailing Trade Winds are offshore
and there is practically no rain The air is dry, the
heat is intense and the relative humidity slow. Days

E

£
L

Place: Rome, aly (42, 12.)
Altude: 207 foot
‘Annual precipitation: 3 inches
“Annual temperature range: 21°F (18-45)
Fig. 135 (a) Mediterranean Clim
hemisphere

EHE
: i

DAMA SONO

Place: Cape Town, South Africa (24S, 18]
ae Tow Alca (34, 18.)
Annual precipitation: 25 inches
‘Annual temperature range: 15 (70-55)
(0) Mediterranean Climate in tho southern
hemisphere

the Mediterranean regions
stains of some kind. In

la pren an eve barr to the oF
is AS a result the Portuguese
caste Spain, Lisbon has an

plone the eastern coast of Spain docs not nea
Gen half as much. Much heavier prespitation has
been recorded in the highlands on windward slopes
facing the Westerlies The step hills of the cate
Adriatic are the rainest part of Europe with 182
inches recorded at Crkvice, about 3,600 fet above
sea el

Rain in Mediterranean Europe normally begins
in September, reaching its peak. somewhere in
October (5 inches in Romo). Though the down.

pours are infrequent they

districts, destructive fc er
Te Noods come so siden tha thee is pray
lo tine to do anything about i The dissout
food of Lisbon in 1967 came in he middle of the
High and cased gest damage and loss of ie in
Show tardy oorurs on lowlands and coastal
it and een i does fll onthe highlands
"modera and à source of water supply for hydro
fete power generation and for trian,
Bright, samy nether with ot dry summers and
et mil winters. Considering is mid-atude post
tion, the Mediterranean regions have avery fou
able climate unrivaled by any other lat regions
The climat features are transiional between those
of the Trade Wind Hot Desert in the south and the
Cool Temperte Martine Climate in the north
Summers are warm and bright and winters are so
nil and cool tha many tours come at all times
Of the year The shy i almost cloudless and sun
Shine à always abundan In July, Rome has as
much as eleven Hours of sunlight) and with the
Mediterranean palm res around, tourists fc very
imuch as if they are in the wopk Even in mi
Summer, the intense heat iy never sy. The
combine effets of onshore winds and he marine
breezes Hee the temperature down to about SF
in winter and not often exceeding 75 in summer
“he climate i so mil that many of the local people
sep in the open ai The anual temperature range
seen 15 and 25°F The Mediterranean regions
are famous for their health and pleasure resorts,
frequnted by miis at round the year
44 The promincce of local winds sound the Med
teranean Sea. Many local wind, some hot, others

ny
region with the high Alps in the north, the
the south, continental interior in

— oia winds

Fig. 136 Local Winds ofthe Meciterancan Sea

to great diferenoes in temperature, pressure and
precipitation, The passing cyclones from the Alan
Ki, the antcycones from the north, and the cold
air masses from the continental” interiors are
‘often interrupted by rei Features,
resulting in the birth of local winds around the
Mediterranean, These winds varying in strength
direction and curation afec th lives, crops and
cities of the people there. Fig. 136 indicates
the location and direcion of some of these local
Winds and the more important ones are described
below.

(8) Sirocco. This is a hat, dry dusty wind which
originates in the Sahara Desert. Though it may
xcur at any time of the yea, itis most frequent
in spring and normally lasts for only a few day
The Sirocco blows outwards in southerly direction:
from the desert interiors into the cooler Meditera-
mean Seu. It is usually associated with depressions
from the Atlantic passing from the coast eastwards
inland, After erosing the Mediterranean Ses, the
Sirocco is slightly cooled by the absorption of the
water vapour. Even then, it is stil hot and dry
with a temperature of over 10S*F. Its sorehing
breath withers vegetation and crops. The damage
is particularly serious when it comes at the times
during which vines and olives are in blossom. The
Siroceo is so prominent that itis called by many
other local names, such as Chil in Tunisia, Gib
in Libya, Levcche in Spain, Khamsin in Egypt and
Malt, In the Adriatic and Aegean Sea, this hot
wind, beter known as Gharbi, gathers much mois
ture causing fog, heavy dew and rain. This may be
“blood rat because the wind is carrying the red
dust ofthe Sahara Desert.

(0) Mistral. In contrast, the Mistral is a cold
vind from the north, rushing down the Rhone valley
in violent gusts between 40 and 80 mies per hour.
‘The velocity of the Mistral intensif by the funnell-

us
PP

in the valley between the Alps and the

0 and in extremo cases ins may be
led and Uses uprooted. In winer when the
“Mistral is most frequent the temperature of the wind
‘ay de below fering point, tough the sky my
be clar and cloudless a protective measure
‘many of the houses and orchards of the Rhone
als and the Riviera ne thick rows of tis und
edge planted to hic them from the Misa.
A similar typeof cold ortveasel wind expe
Sd along the Adriatic cos called the Bora
Like the Mina iti caus by a dies in
pressure beten comical Europe and the Medi
emanan. This usually occurs in winter, when the
amor prsure over continental Europe. à

‘aks of Spain and Portugal are the best known, 7,
are found only in the elimatcally m
regions with a rainfall of well over 2 =
trees are normally low, even stunted. with mas
trunks, deeply fissured barks, small leuhen nS
and a wide-spreading root system in scat
The cork oaks are specially valued for
brs, used for making wine-bottle corks snd”
export around the world. In Australis, the cacy
us forest replace the evergreen oak. The san
and kari tees are commercial the most impor
The slant sequoia or redwood is typical of pe
Californian trees.
2. Evergreen coniferous trees. These include the
various kinds of pines firs, cedars and cp
have evergreen, needle-shaped leaves and ral
straight trunks They appear more on the coole
highlands and where droughts are les severe De
forestation has reduced ther numbers considerably
3. Mediterranean buses and trab. This spans
the most predominant type of Mediterranean ve
tion. Summers are so dry and hot that in paco
forests give place 10 short, cvegrcen shrube and
bushes. The low bushes grow in scattered. clumps
and are often thomy. The more common species
are laurel, myrtle, lavender, arbutus and rosemary
of which a number are strongly scented or perfumed
In many areas, due 10 mans interference in
the original
10 a Scrub vegetation with

ret depletion, on wo rec
woodlands dente

Seated, tuned es and al bushes They ar
dierent rom the onary wondand othe Woe
ser serubland that special names have ben gen
lo them to dsingush their locaton lo dient

Parts of the Mediterranean lands. This type of
Vegetation js called maquis in southern France, and
‘macehia in Italy. In California, the term chaparral
is used and in Australia malls scrub. In limestone
‘uplands, where the soil is extremely thin and the
Serub deteriorates into hi

folla readily, and

dssrnenctaing root, is Test

Even this form of grazing has done more harm than
400d for it has promoted soil erosion and impover
ished the hillslopes of the Mediterrancan. Animal
fats are not important here and the chief cooking oil
is obtained. from olives. Dairy pi

impor items.

Economic Development

of the Mediterranean Regions
Despite the semi-arid conditions over many parts
Of the Mediterranean lands, the climate as à whole
is favourable. is warm, bright summers and cool

mean shorelands were once the cade of ord
lation. Nowadays the arca à important for
frit culation, cea! roving, winesmaking and
Aura) industrie, as well as eninering and
Mining We shall del with some of them in seater
etal below:
1. Orchard farming. The Mediterranean lands are
also Known as the worlds orchard lands. À wide
| range of ers rl sch as range, tons, ines
‘tons and grapeiut ae grown. The rut tress
fave Tong rs to draw water from considerable
| depihs during the Jong summer drought. ln excep:

ii

iE ee

WANS

NINAS
DIAS

ny arcas, riacion helps t0 relieve the
re. In the Great Valley of California,
le, the Negev Desert of srl and the
northern shores of Mediterranean Europe, an elabo-
system of irrigation canals enables both fruits and

full raised. The thik, leathery
bts prevents excessive Irunspira-

era 10 be sue
skin of the citrus
tion and the long, sunny summer enables the fais
to be ripened and harvested, The various Mediterrar
can oranges are so distinctive in their shape. size
taste and quality that they are called by diferent
james in ther area of production. OF the Meditera-
‘oranges, perhaps, the best Known are the
Sunkist oranges from California, exported for table
consumption and for making orange squash. The
Seville oranges of Spain are small but very sweet
nd are particularly suitable for making marmalade,
Those from Israel, the Jia oranges, are equally
delicious and are specially grown. for export. In
Tangiers the tangerine is of great local importance,
Inthe temperate monsoon lands of China and Japan,
hich were, in fact, the native home of the orange,
‘commerical cultivation of the fui isles significant,
and only in recent years has there Been any serious
‘fot made 10 popularize thet export as “mandarin
oranges” The Mediterranean lands account for

145

per cent of the world’s exports of cas fruits
rei probably the mos ypica of all
culated vegsation. I i o hardy

tat it can survive even on very poor

ls with Jess than 10 inches, of annual

our enconut palm, the olve tee is

and has many uses The olive can be
hor pil with spies. The fleshy part
rushed and olive oil extracted, valuable
cooking ol in a region deficient in animal
margarine can alo be made with
lives many ut res like chestnuts,
hazelnuts and almonds are grown and the

ms cherries and igs
OP cultivan. Besides orchard fruits, the
imate also supports many field
by far the most important.
the leading food crop. Though conditions
‘wheat cultivation are not

and other food product such as macaroni,
sand vermicelli The farmers usually sow
autumn, so that they germinate and grow
ai. By spring there

Sometimes cate Transhumance is widely practieg
Wie reste Ts usa a
Mediterranean countries, because the best wine ©
senil male rom spe Some $5 pur sen
GE pares proce’, po io pin The lore ve
imine allows the pesto pen and en hen.
NS
Kerman spain ud e regions borra
Meeranen Sea scout fr tire ques à
Words production of wine In Span, Por
Frans, and ay wine the national The
eee wise consumption of the Moderar
mines abe 15 als per had pr ann
meh!

Although grapes may be grow in many parts of
the temperate nde sommer vice 5 a
os ently conte fo the Mehr ron
I has ben sm tht 0 lion tors te
Words ol production of 46 milion ons or arpa
anal ar Bing prod into wine Te qua
he fermented grape juices deed by namen
al fon including the types of ines bn, the
qual of the wi the imate ofthe tein, the
meihol and ext of fementaron. The hagan
fast nd quay of the na product so varied ha
the ie age ten ino my te
heap à any sofi or as expense brand
To Gin the various Kinds of wine the
principal wine ares of the word maintain the
Slate names The wine fom southem Spain

tapes are grownin many Mediterranean counties. In
“Tia ome are did tomate sultanes Tey are washed
and the id out In he sun Pau! Popper

js called s
ie and marsala come from different parts of als
Ih France the greatest wine regions are located
further north, eg. Champagne in the Paris basin,
Bordeaux in the Garonne basin, Burgundy in
Rhone-Suone valley.

The world trade in fresh grapes is comparatively
small mainly from Mediterancan South Africa.
Most of the inferior grapes are preserved as dried

ames 6g. currants From xapes, rains
fom California, and sultanas from Asia Mino

The other industries associated with Mediterra
ean agriculture are frit canning, four milling and

food process

QUESTIONS AND EXERCISES

1. What is m
climatic type
index plants repr
climate indicated?
(a) teak- Tropical Monsoon Climate
() olive Mediterranean Climate
(©. cactus Hot Desert Climate
(6) spruce Cool ‘Temperate Continen-
tal Climate

nt by the index plant’ of a
in what ways are the followin
sentative of the type of

2. The following statistics of the annual
fainfll and annual temperature ranges of four
Mediterranean lowland stations are taken from
ranean shorelands. Attempt t0 eX
lin their diferences

ing statements about economic

3. Outline the various types of natural vege
tation found in the Mediterranean regions
Relate this to climate, soil and human

4. Give an explanatory account of the follow

of the Mediterranean lands

©

isthe predominant

‘chief coral cultivated is hard,
winter wheat.
Pastoral farming of litle importance

5. Write geographical notes on any three of

the following

@

©

@

The Mediterranean Climate is typified
by dy sunny summers and wet, mild
Hot, dusty Siroco and cold stormy
Mistral.

Mediterranean woodland shrubs and
scrub

‘Three-quarters of the words wine
comes from the Mediterranean regions

147

Inthe southern hemisphere due to the marron
Of the temperate portions of the southern contes
the grasslands are rather restricted and less conten
fal, In the ease of the Pampas of Argentina and
Uruguay, the grasslands extend right to the sca und
enjoy much maritime influence. In South Africa, the
grasslands are sundwiched between the Drakensberg
and the Kalahari Desert; and are further sub
divided into the more tropical Bush-ved in the north,
and the more temperate High Vel in the south, The
word veld’ is a Dutch word given by the carly
Pioneer Dutch farmers who came 10 setle here
Ik means ‘field’ and is promouncod as ch. In
“Australia, grasslands are better known as Downs
and are found in the Murray-Darling basin of

Climate
“Temperature. Their location in the heart of con-
finents means that they have litle maritime influence

Winnipeg for July, as ilustrate in Fig 1
TE. for January for Pr

ers are very cold in th
Eurasia because of 1

enormous distances from the
The winter months are well below
snipe the January readin

In contrast, the steppe type of climate in the
southern hemisphere is never severe. The winters
mild thatthe mein temperature for a
he winter months is usual between 39° and SS
Temperatures below freeing point even im mid
winter Qu in the southern hemisphere) are
exception. Pretoria, the station chosen o illustrate
the steppe type o climate in the southern hemisphere
has SE. in mid-winter Qui). the coldest month
of the yeu. Sta other parts ofthe south
continents also show a mild inter. For example
the July mean (mid-winter) for Johannesburg is 49°F
for Buenos Aire, 49°, and for Mildura (Murray.
Darling bain) 49°F, These statistics establish the
moderating ess of oscans on the climates of the

© of temperature is great, a direct
result of continentalty. Winters are so cold that
parts of the Eurasian Steppes are snow-covered
for several months. The snow mes with the return
“nd by mid-summer, temperatures sûr (0

Te is really hot for its latitud. For
example, the mid-summer temperatures for Kiev is
STE. The stations in the southem hemisphere
record cien higher temperatures, cg GE in
TE in Buenos Airs and ME.

ion: 20 inches Johannesburg,
4) in Miura
the northem lis clear from the two selected stations given

‘Annual prop

‘Their climate is thus continental with extremes of ae

temperature. Summers are very warm, over 66%

that there is a tremendous difference between the
annual temperature range of the northem and
Southern hemisphere, again a factor of continental
‘The range in Winnipeg, in Fig. 138), is TUE
nearly three times as great as that of Pretoria, in
Fig. 138(b), at 26°F Readings taken in various
other stations of the northern and southern hemi-
Spheres confirm this tend. The annual range for
Mukden in Manchuria is 69°F In comparison, the
annual range of the more maritime stations. of
Johannesburg, Buenos Aires and. Mildura in the
Southern hemisphere are very much small 20°F
25°F. 28°F. respectively.

Precipitation. In its continental position, the annual
prespitation of the Steppe Climate can be expected
to be light. The average rainfall may be taken as
about 20 inches, but this again varis according 10
location from 10 inches 10 30 inches Winnipeg,
in Fig. 138%, has 20 inches with distinct summer

by the occasional d of the Wester and
‘coming in the form of snow. In many other con-
‘ental stations, the annual precipitation is even
ess though the general patern remains the same
With most of the an ling inthe summer.

‘The maritime influence in the steppe ype of
climate of the southern hemisphere is even beter
Sought out by the ram rem le an
piton is always more than the average 20
inches because of the warm un curents that

ember, January and February, the summer season
of the southern hemisphere There are three months
ans, July and August) without any rain. This is
‘the period of drought that may have such a disastrous
¡lec on the sheep rearing industry here. The dry
season is particularly pronounced in temperate
‘grasslands adjoining deserts, for example in Australia,

Mildura, on the finge of the mall scrub of the
en ‚and also in the rain shadow
srs ate Gr Ding Rang, as a an
sil of only 106 inches Iignion 5 ese
“other southern hemisphere stations, have mo
os 20 inches in Johannesburg and

— A
a local wind, similar to the Fohn in
the Chinook, comes in a south.

o the Pris and has a consider.

local pastures. I actualy comes

in winter or early spring fom

the Rockies and then

Ie is natural to expect the steppes
covered, differing only in the dons
the grass Their greatest dif
savanna is that they are practically ns
frases are much shorter. Where the rant
moderate, above 20 inches, the

ind nutritious and are better dew

This is typical of the

better watered aras of the Asiatic St
the rainfall i ht (es han 20 i

or the sol poor a in

Asi the sho prevails Th
grass are not ony shorter but aso wiry and spur
often found in discontinuous clumps, with bare so}
exposed between them. These areas are ls sia
for arable farming and are used for some torn
Tanching as inthe High Plans of USA.

The climatic requirements of
dient from those of trees. They
molto than trees and an annual precipitation of
10 to 20 inches is adequate. Their growth isn
Abrpiy checked by summer droughts or winter
cold, The steppe gros can throughout
the prolonged doma. Thy spout and com lo
life as soon a Ihe temperature fs warm enough for
plat growth (SF) und grow sad, with wey
litle moisture

The appearance of the temperate grasslands vrs
With seasons In spring the grass begins to appear
green, fresh and blooming with small, colour
flowers The light rainfall that comes in late sping
And carly summer greatly stimulates thir growth and
Abres plenty for he animals to graze, The herdsmen
ae busiest a his time In summer, there 50 muc
heat and evaporation that the grass is scorched
The carpet of bish-green grass tums yellow and
Seon brown, Towards autumn, the gras withers
and des, but the root remain aie and ie dormant
throughout the cold winter The winter 5
harsh and long, but the snow is never of great depth
Everything is quiet but with the next spring, the
se repeated and te steppe is alive again.

Tis are very scarce in the steppes, because of
the sant rainfall, long droughts and severe Winter.
The rolling plain is an endless stretch of grass
whether green or brown, except along the water
courses where afew low wilows, poplars or alles
break the monotony. Polewards, an increase if
Peston gies ie 104 trasonal zoe of

“wooded steppes where some conifers gradually

Tho prairies, Saskatchewan, Canada, Notice the grain elevator by the allay line National Fi Board of Canada

“appear. Even then, the res are very scattered and
few in number, Towards the equator, the steppe
ras becomes shorter and sparen, til t merges nto
the desert with thomy serub

In the cultvatod regions, such as the whest farms
of the Prairies, double rows of tee i
“around the house to shield the occupants from the
‘trong winds which come unobstructed across miles
of Keel ground, This provides the greatest contrat
in a land which is essential grass There are no
edge and few fences and the rows of planted tres
orm an unusual landmark from the ie

Economic Development
‘The temperate grasslands were once the home of
racing animals; wild horses in the Asiatic Steppes
swiftfooted bison in the Prairies and untamed
bulfaloes in the Pampas. Even as recent. as the
last century, these grasslands were dominated by

ind semisnomadie peoples like the Kirgh=

of the Asiatic Steppes. They roamed far and wide
with their herds and earned a precarious living from
hate pastures they could ind. The Red Indians
fof North America were mostly hunters who moved
around after the bison and other animals. Cult
ation was unknown and the region Was one of the

ost sparsely populated parts of the world. In
cent years great changes have taken place in the
gruslands and few arcas in fact; have managed 10.

tin their orginal landscape. The graslands have
been ploughed up for ext
caltvtion and are now the of th

Besides wheat, maize is increasingly cultivated in
the warmer and wetter areas The tud erases
have been replaced by the more nutritious Iserne
or alfalfa grass for cattle and sheep rearing. These
temperate graslands are now the Fading ranching
regions of the globe, We shall now describe more
Closely each of these economic activites.

À Nomadic being, This type of migratory animal

FE 0)

“Brazing has almost disappeared from the major
“stings The dr er waning ts ce
Kirghiz, the Kazakhs, and the Kalmuk, They warm, sunny sun

From

meat milk, wool, hides,

11 travel ovr long distances Ike the Bouin ane
the Arabian Desert in such of gris and wer fr fun
their animals-cattle, sheep. goats and horses.
à these domesticated

ue In addition,

time. E

: The bones and hors were not wasted but gathered,

de into tools, utensils and weapons. Many of

homemade products were exchanged at trading
‘OF with the caravans for guns, canned food, — For example, the avera
ta, coffe, sugar, medicines and othe essential

harsh environment of the nomads, with long
his and unreliable showers made the Downs, the yields are e
20 bushels per acre! In comparison, the wheat vida

{in countries that practise intensive fami
higher, at times almost thrice the yield. It i 50
bushels per acre in the United Kingdom, 57 bushels
in Denmark and almost 59 bushels in the Netherlands!
attention given 10 a

which is not practicable in
inds where a farmer owns
anything from 600 10 40,000 ares as in the Prairie.
But if we consider the yield per man, this is very

ane eer oa
ed
‘The cool, moist spring stimulates early

Facts Th

‘This is attributed 10 the gre

Earth region of Ukraine, part of the Eurasian Steppes

growth and the light showers in the ripenin

hep to sve the grins to ensure a good yet
ner is not only ad

y, but also enables the straw to be

ee pas
O ee ee a ob and reino «=
te et ei cay fou Mena pouch
osado intra an home Su
[out of thee The wo vas voten ‘no fh for pos
ens garments Te lester as wd for making Pampas. the Ukrainian S
“boots saddles and ti which wore vr) exon

a coun whee the te ings as the

elds ready for sowing in the
the Prairies
eppes and the Downs of
Australia combinesharvesters. reap, thresh, winnon
and sack the grains almost as soon as the st

‘One distinct drawback of this form of extensive
mechanized farming is the con
yield of wheat in the
Prairies is about 23 bushels per acre (1 bushel is
“approximately equivalent to 60 Ib. in weight or §
gallons in volume). In the Pampas and the Australian
n lower, not more than

. Canada. In the warmen, w
A ship is loaded with grain for export at Port Arthur, inercial ern
Ontario Pau Popper 3

Pastoral far

he USAS A
USSR

T

I is best fr bread-making and is extensive
Polewards, where the winter tempera

14. In North America, winter wh
outh ofthe Great Lakes in USA, while
pring wheat is sown mainly in the Canadian Prairie
provinces of Alberta, Saskatchewa and Manito
Scent plant b has now devised cold
sant vais that can mature within 110 days
This hs resulted in the northward extension of the

Peace River region in

When pioneer seers fist

much higher in the extensive farms In this respect, moved into the temperate grasslands, there Were
the sparsely populated temperate grasslands of the ver few animals, The natural conditions sit animal
midtitudes pro atest quantity of wheat farming. Subsequenti etl, sheep, pigs and h

were introduced, à
“development of ref

world’s wheat-gow
aly the greatest Wheat With th

per capita amongst th
nations, They are, nat

d they proved very succesful

exporters. Three-quarters of Canada’ 10 milion nineteenth century, the temperate grasslands became

tons of annual wheat production is exported, mainly _ major past ns. exporting
to Europe which does not produce sufficient wheat to of ‘ef, mutton, wool, hides. Mil,

feed her very dense population, despite

parts of the North Ame

Southern hemisphere, (Figs 141,

| Fig, 140 Wheat and beet production in the North American grasslands

‘quantities
butter, cheese

ES can grasslands. The
OS
12 and 18)

where the winters are
‘evenly distribute.

der and the rainfa ig

he original Ror

ploughed up and replaced by sown al
a em ve
eo
D ee een

lead in the worlds export of bee. Large esmas
(neatpacking factories) in the coastal ports We
fae mon of ud and male The rl
nn eme
D me
co
En 2. Aa bone
nn mn
QUESTIONS AND EXERCISES

1, Compare and contrast tropical
and temperate grasslands in respect of
(4) their seasonal responses to climatic changes
() their economic importance

2. Each of the following temperate grasslands is
paired with an important aspect of ts
economic life
Forany tre of them, give a reasoned account
(6) Asiati Steppes nomadic bending
(b) Canadian Prairies spring wheat cutation
(© Argentine Pampas: beet cattle ranching

0) S African Ved: maize growing

0) Australian Downs: sheep grazing

aval temperature range of Winnie
uch greater than that of Porn,

re more frequent in the
inter are milder.
ils in the Pampas are much

of Denmark,

a

Chapter 21 The Warm Temperate Eastern Margin

(China Type) Climate
Distrib

This type of climate is found on the eastern
just outside the tropics (Fig. 144). It has compare
tively more rainfall than the Mediterranean climate
in the same latitudes, coming mainly in the summer
Iti. in fac, the climate of most parts of China a
modified form of monsoonal climate, I is thus also
called the Temperate Monsoon or China Tipe of
imate. In south-eastem USA. bordering the
Gulf of Mexico, continental heating in summer
induces an inflow of air from the cooler Atlantic
‘Ocean. Though les pronounced, the overall climatic

ures resemble those of the China type. I is
sometimes referred to asthe Gull type of climate

In the southern hemisphere, this kind of climate
is experienced along the warm temperate eastern
coastlands of all the thre continents: in New South
Wales with ts eucalyptus forests: in Natal where
ane sugar thrives; and in the maize belt of the
Parana-Paraguay-Uruguay basin. As the regions
are influenced by the on-shore Trade Winds all the
ear round, without any monsoon variations, the

ents in warm temperate latitude,

climate cannot be described as temperate monsoon
Te is sometimes refered 10 as the Natal type of
climate

Climate
The Warm ‘Temperate Eastern Margin Climate is
typified by a warm moist summer and cook, dry
Winter, The mean monthly temperature varies bes
tween 40°F and TSF. and is strongly modified by
maritime influence. Occasionally, the penetration
fof cold air from the continental interiors may bring
down the temperature to freezing point. Though
frosts are rare they occasionally occur in the colder
interiors. For most of the time, it is pleasantly
arm, The relative humidity isa litle high in mids
summer when the heat becomes oppressive and can.
e very ring 0 the white settlers, eg. in Natal
Rainfall is more than moderats, anything from
25 inches to 60 inches. This is adequate for all
‘agricultural purposes and the Warm Temperate
Eastem Margin Climate supports a wide range of
crops. Areas which experience this climate are very

Fig. 144 Rogions witha Warm Temperate Eastern Margin Climate

‘densely populated. Another important feature isthe
fairly uniform distribution of rainfall throughout

the year. Thee is rin every month, exept inthe
interior of cel China, where thee is distinct
Ary season. Rain comes iter fom comecioral
Sources or as oras rain in summer, or from
sessions in prolonged showers in winter, Local
‘storms. eg. yphoons and hurricane as cur,
en Boo df arto i in
astra mangos and it is eset 10 examine
them by reference 10 specific aca, whee the local
actors af the climates. We shall substvde them
no three main types
1. The China type: central and north China,
inldin southern Japan (emperte monsoon,
The Gulf type: soueasern United State,

3. The Natal te: al the warm temperate eastern

2, oonsmonoonal aris) of e southern

including Natl, caer Australia and

"southern Brail—Paraguay—Uruguay and northern
Argentina,

Te China type. This is the most typical climate
Of the warm temperate castem margin, The great
of the Alte continent wih its mountain

or induces peat pressure changes between

2 Hosting in ‘the heart

iar an dns

al steam is drawn in as the

Monsoon,

Place: Nanking, China (32,119)
Altitude: 34 re
‘Annual precipitation: 42 inches.
‘Annual temperature rang: 45 (81139)
Fg. 145 (0) Warm Temperate Eastern Margin Climate
inthe northem hemisphere (China type

South and along the cost, the temperature differences
ate much les eg, 28% in Canton, 27°F. in
and only 22% in Hong Kong.

Another climatic feature associated. vith the
China type of climate in southern China à the
Sesuence of Wphoons “intense tropical cyclones
that originate in the Pac Ocean, and move west
Yards to the cosslands bordering the South China
Sei. They are most frequent in te summer, from
July o September and can be very disastrous. The
Winds blow with tremendous strength the sky is
test and there are torrential downpours As
much as 24 inches in a day have been recorded and
food is widespread. In the Swatow typhoon
of August 1922, he huge waves set up by the violent

drowned as many as 50.000 habitants.

‘phoon
2, The Gulf type. The Gul-Alanc regions ofthe
Jed Sites experience «type of climate similar

Tor
He PAUSE

i San ET

2 EE y =

: H |

; E ;

OT FMAMI IASON D OT FMAMILAS OND
er Te

Place: Miami, Forde, USA. (261, 20)
‘Altitude: 5 feet

Annual precipitation: 5 inches

“Annual temperature range: 1 (82-68)

(b) Worm Temperate Easter Margin Climate
inthe northern hemisphere (Gul type).

Summers are warm and pleasant, Miami, being a
important holiday resort, and it rarely snows in

‘The annual rainfall is heavy with 59 inches in
Miami, and New Orleans; 52 inches in Montgomery
and 4 inches in Charleston. There is no distinct
Ay period as in monsoon lands, and the abundant
‘moisture has stimulated extensive cultivation of
coton and maize inthe Coton and Com Belt both
of which are the works leading areas for these eros.
From the rainfall pattern in Fi. 148 (it lear hat
there is a tendency towards a Summer maximum,
brought by the onshore Trade Winds which swing
Jandwvards from the Atlantis. The amount of rin
is increased by the frequent thunderstorms in summer
“nd by hurricanes in September and October

Some stations eg. Montgomery in Alabam
lso show a secondary maximum in late winter when
‘clonic actives are greatest. Sometimes, violent
{ormadoes oscur, due to intense local heating on
land, Though these whiting storms follow only a
‘narrow path in the central plain (Mississippi basin),

ion.

eave b ie =

Place: Sydney, New South Wales, Australia
(rs, 151)
‘Altitude: 138 feet
‘Annuolpreciptaion: 48 inches
Annual temperature range: 19 (72-83)
(6) Warm Temperate Eastern Marin Chat
In the southern hemisphere (Natal ype)

induence climinst the monsoonal elements which
characterize the corresponding climats ofthe north
Sm hemisphere The South-East Trade Winds bring
about a more cn distribution of rfl thoughout
ihe year as ilustated by the climatic graph Tor
Sydney, Australia. I has a mean monthly presi
tation of 4 inches, whichis adequate for most agri
cultura actives The annual amount of 48 inches
À fly representative of this climate type ia the
Southern hemisphere The annual pesiptation of
Durban in Natal s 4 inches and tat of Asuncion im
Paraguay i 52 inches The passage of depressions
sos the southern edges of the warm temperate
‘eastern margins results in a slight autumn or winter
‘maximum, pied by Syüney (Fig. M46) which
Jas its ets months in March, April, May, June
and July (the autumn-winter part of the year), The
rain comes in prolonged showers. Much of the
Far he ind an te ee
‘so the regions are well suited to agriculture :

sae of the bs sted part of he othe un

only SF, and the climate is pleasantly warm all
the time.

However, the southern continents also have
Wiolent local storms, which, though not as severe
asthe typhoon, hurricane or tornado are nevertheless,
quite significan. The Southerly Bunter. a violent
‘cold wind blowing along the coast of New South
Wales leads to a sudden fallin temperature. It is
most frequent in spring and summer. The cores-
Ponding cold wind in Argentina and Uruguay is the
Pampero, which is often accompanied by thunder
‘and lightning besides the rain and dust. In south.
sem Arica a hot, dy wind called the Berg Wind
¡Comes down from the interior platea. It is compar-
able to the Fohn or Chinook, and brings unplea
santi high temperatures and oppressive weather,

Natural Vegetation

The eastern marins of warm temperate latitudes
ave a much heavier rfl than citer the western
‘margin or the continental interiors and thus have a
Turin vegetation. The lowlands cary both eve
green broad-esved forests and deciduous trees quite
Similar to those of the topical monsoon foresis
‘On the highlands are various species of conifers such
4 pines and cypreses which are important soft
‘woods As the perennal plant gromh not checked
‘by citer a dry season a inthe Mediterranean, or a
‘old. season as in the cool temperate. regions,
are wel suited ta ich arc of plant life
ms, ianss,bamboos, palms and
is The well dbtributed rainfall all the year

te regions look green at ll times.

warm Mozambique current encourages hy
pitaion along the coast and m
trees thrive. The highlands yield extensive
of chestnuts, ronwood and blackwoods À
‘occupation is the commercial cultivation «
Ares in plantations for tanning extracts and for un
in Natal coal mines as pltprops

‘The forests of Chin
considerable economic value and include
phor, camela and magnolia, Unfortunately the
tremendous population pressure inthe tw
as caused much of the original fo
for fuel or crop cultivation, na
resulted. in many barren hillslopes that are stil
feeling the impact of soil erosion. The Gulf states
of USA. have lowland deciduous forests The
Axes grow close together with thick undergrowth
and leafy branches. Walnut, oak, hickory and
maple are some of the more common species while
in the more sandy regions grow pines Much of
the forest cover has given vay to the cultivation
Of sub-tropical erops like cotton, maize and fruits

st to be cleared

Economic Development

The warm temperate eastern margins are the most
Produetive parts of the middle latitudes. There is
Adequate rainfall, no prolonged drought, and the
Sol season is warm enough for most erops to survive
‘Thus the growing season is almost continuous,
though summer is the busiest part of the farming
year. Monsoon China together with southern Japan
and other parts of the eastern margin climatic zone
‘accounts for almost a third of the world population.
Food has tobe raised to feed the teeming population,
‘The hills are terraced, fields are irrigated, and agri=
‘culture is extended to the limits of production. Its
no exaggeration to say thatthe temperate monsoon
lands are the most intensively tilled parts of the

arth. Besides the widespread cultivation of maize

and cation inthe Com and Caton Bs of USA
Tht and tobacco ae also grown. Rice, ten and
Are extensively grown in monsoon China
are found other products of czonomie
importane, eg. cane sur in Natal, coffe and
‘naz in South America and dairying in New South
Victoria. Let us now examine some of the

Ne por as
Ent
PRE
import

4 Land fr ice forming in Ja

other food grains are essential. The Chinese pea
sants rase ‘wet pad or ‘swamp rice in Hooded
feds that call for endless had labour for the greater
part of the yea. Iti said that nowhere leis there
50 much manual labour devoted to raise a food crop
that gives so litle economic return. Farming is
usually on a subsisenco basis Despite increasing
mechanization in padi-ultvation, very few farmers
actually make use of new machines because they ae
expensive and may be impractical in some ares,
‘The only progress that has been made is towards
double or tele cropping, which has increased the
‘annual total ie production. When compared with
the rapid. population growth of the rice-cating
nations, the increased production has in no Way
relieved th critical food problem of Monsoon Asa
Furthermore, mild ie which forms the stable food
of the Orient is seriously deficient diet; the people
ar therefore not only inadequately fed also physialy
undernourshed.

“Monsoon China has all he idal conditions for
padi cultivation; a warm climate, moderately wet
throughout the year, and extensive lowlands with
fertile moisturesetentive aluvial soi, which if neces-
ee un
tilled from generation to generation, and yet
litle deterioration in soil feriliy, The muddy

aly brings new soil to the fields. The water
ed during foods, though these are
vent now, with the improvement made

od control by the Communist regime. In
practice, the Chinese peasants add all kinds af
+ 10 enrich their fields Rice stom,
x, clippings, animal dung. refuse, and last but
The most intensively farmed areas are the basins
of the Sikiang, Yang-te Kiang and Hwang Ho,
which are also the most densely peopled. areas
The eastern coastlands are equally important. As
the fat lands are insufcient for rie cultivation,
Farmers move up the hillslopes and grow padi on
terraced uplands. The artificial terraces retain the
‘excess water as it flows down the slope. Besides rice
the other important crops are ca, grown. for home
consumption and mulberry leaves gathered for feeds
ing sik worms, though serculture is declining
2. Agriculture inthe Gulf sates. Agriculture in the
Gulf states of America diera from that of monsoon
China, though they have a similar climate. Lack
‘of population pressure and the urge o export, make
rice cultivation à relative unimportant occupation.
Its grown only in a few areas in the southern coast-
lands of the Mississippi delta. Americans are bread
‘eaters and one can well imagine how insignificant is

rice in the economy of the Gulf states The most
important erops are corn, cotton and tobaceo,
a) Corn. The chief food crop raised i, in fact

com or maize, The humid ai, the sunny summer and
the heavy showers suit the crop well. I is grown
right from the Gulf coast to the Mid-west south of
the Great Lakes, with the greatest concentration

the Com Belt of Nebraska, Iowa, Indiana and
Ohio. The region accounts for more than half the
worlds production of corn, but oly 3 percent of the
worlds export. This is because most of the com
is used for fattening animals, mostly cattle and pigs
Many farmers do not harvest the com but instead
allow the catle or pgs to hog the com down! in the |

why His so widely culated in both
temperate and the topical ites

(® Caton, Of the cash crops grown in the
Gulf states none is comparable wih coton. In the
Deep South, the fre i so val to the economic
welrbeing of the southemes tat ‘cotton is Kine!
Tt shapes the destiny of the southem states. being
directly responsible for thir trado. prosperity and
polities In the early days of America milion of
Negros were brought rom Africa a save labour for
the coton plantations, because the climate was 00
ot fr the whit sets to harvest the cotton them
sches Altbough sry was abolished in the nine
teenth century, the Negros ae sil oor and under
prie. This isthe case of the present problems
Ben the Backs and the whites in Amer

The Gulf typ of climate is undoubtedly the best
for coton growing. ls long. hot growing season
‘vith 200 days fost fre and a moderately high ten
Aperture of about 79. permits the crop 10 grov
Soul and mature within six months Like most
fibres, coton ike ample rin and an annual pre
piton of around 40 inches is esentil. In fact
fn adequate moisture supply coming from frequent
Tight showers with bright sunshine between them
ies the highest yield. Fine quality coton also
Some from gate fel inthe dir west provided
Salen water supplied during he growing season
“he Cotton Betis ths limited bythe 20-inch soyet
"USA isnot the ony important an producer nds
largest insti

sy coton totes. Here ya being
atthe Ba rls New De Press Information

‘on the west and 77°F isorh
within which there

frost. Inthe

heavy rainfall damages the lint. This area is then
fore les suitable for cotton and is d E
fruits cane sugar and market gard Flora

The commerical cultivation of cotton is now con
úcsntrated only in the most favourable arcas which
are the Mississppi flood plains, the

cosstlands of Georgia and South C
Black Prairies of Texas and the Red Prairies
Oklahoma. Fig. 146 shows the chief co

Generally speaking, the best cotton < n
the maritime districts where the sea breczes and 1
warming effet of the orean are most strongly fel
‘The Sea Island Cotton grown in the islands off the

coast of Georgia and South Carol
(the fibres are between 1S and 23 inches in length)
and is the best in the world, Further inland, y
Staples are shorter (about an inch long). This is
typical of the bulk of the ‘American’ cotton, Be
sides the problem of soil exhaustion and
caused by prolonged cotton cultivation

dreaded enemy of the Cotton Belt i the boll-esi
The pest multiples so rapidly that a pair of ball
weevils if left unchecked, will breed over 10 milion
grubs within a single season! The pestis responsible
Tor the westward migration of the Cotton Belt

A

When it fist appeared in 1892 in the eastern US
it attacked the Sea Island Cotton. Aerial spray
with inseeiides and the thorough burning of old
cotton stalks, have been found effective in eliminating
the bol-weevil,

(©, Tobacco. Another interesting crop closely
associated with the Gulf type of climate is tobacco,
‘which incidentally is alo a native crop of America
‘Though itis cultivated in many parts of the word
and the finished products range from Turkish
tobacco to Havana cigurs and Malaysian cheroots,
there is none so universally known as the Virginia
tobacco, Ne is the raw material from which most
of the world’s cigarettes are blended to suit the
Smokers’ taste. The humid atmosphere, the warmih
and the well-drained soils of the Gulf states, enable
Tobacco to be successfully cultivated in many of
the easter states of USA., eg. Virginia, Maryland,
Georgia, North and South Carolina, Kentucky and
Tennessee. No less than hall the tobacco that
enters international trade comes from these states
Regardless of the views that doctors and schoo!
feachers may hold, cigar and. cigaette-smoking
has long been a universal habit that cannot bs

fan industry and

Aispensed with, It is the bass
provide, through dut, a valu
to the governme

4 Crop cultivation in the castern mar
Southern hemisphere. A close Look at the econ
map of the southern hemisphere wil at once reveal

gricultural importance of its astern m
type of elim

the
which experience a Nat
Varm moist summers and frost-free winters not only
Support many crops but also animals In the
oastlands of Natal, cane sugar is the dominant
Crop. followed by cotton amd tobacco in the interior.
Recent expansion ofthese rops has come about with
improved irrigation. Maire 1 extensively cultivated
for use both as “meali an important food item for
‘Africans and ‘silage’, an animal fodder for cattle
fearing, But in comparison with the maize yield
ff the Corn Bet of US.A., the African yield is rather
How, ofien only halk Improvements can be made,

armes attempt some form of crop rotation 10
arrest the rapid rate of sol exhaustion in regions of
maize monoculture. Scientific manuring and beter
methode of eultivation would ras cs.

In South America where rainfall is Less than 40
inches there is much grassland on which many cate
land sheep are kept for meat, wool and hides It is
ihe continuation of the Argentinian Pampas. The
ala winters mean that the animals can be Kept
Sutofdoors all the time The extensive natural
asnos provide valuable forage for both cattle and
een. The products from these two kinds of
“Gomesticated ankmals account for over thnee-quarters
SE Ihe annual exports of Uruguay: The remaining

Fig. 146 The Cotton Bat
& Ana USA

has, Furth
fall increases 10

north soutien Bra ther
D tan 40 ince and forest gradual replaces
Gan ee the important oscuputlns are the
natos of per mate (Paraguay tex) and the
Fantino, of mer or Parma pie, Calle
Msp are raed, and mare and cae ar

Lester Asilo moi Trade Winds bing
teat ntl do the coastal dies and thee
Me IY monde. Gant eualytus tres,
A atone the eer ight up the astern Highland
Shc ant teins of Europea immigrants, mich
M Jos as teen kare. for tement and
Sling, The ester magn of New South Walks
A hc the ut pur of the contient 10 Be
re exaig wih or acon, the prat
Sa Sian The region is now the eet sous
3 ra mk butter and ches bees tn,
o ar and maiz wich are ina ONO
inthe north

QUESTIONS AND EXERCISES

1. What do you understand by the China type
Of climate? Locate on a world map the regions
hich experience this type of climate, and
escrito the broad pattern of their agricultural
activities

2. Describe the main factors which abt the
Simao and vegetation of any thee of the

ta

PEA

10 latitude and other geographical factors the following climate figures.

Aliado.
33 feet

1,700 feet
ES

3. Give a reasoned account of any rv of the
followin,
(@) Cotton cultivation in the United States
of America.
(6) Padi growing in monsoon China
(e) Dairying in easter Australia,
(8) Lumbering in Canada,

Mean Mean Al
January July Temp. Annual
‘emp mn Rome Rail
CO Sins
mE sr nn
ee GE din

(©) USA. accounts for more han 50 per
‘ent of world production of com (ie
‘aize) but only 3 per cent of world
exports,

(@) Farming in monsoon China is usually
‘onasubsistence bass and the peasants
are permanently land-hungry

Chapter 22 The Cool Temperate Western Margin

(British Type) Climate
Distribution
The cool temperate western margins are under
the permanent influence of the Weseris all round

the year. They are also regions of much eyelonic
activity, typical of Britain, and are this said to
experince the British type of climate. From Britain,
the climatic belt stretches far inland into the lowlands
of North-West Europe, including such regions as
northern and western France, Belgium, the Nether-
Hands, Denmark, western Norway and also north
western Iberia. There is so much oceanic influence
on both the temperature and the precipitation tha
the climate is also refered 10 as the North-West
European Maritimo Climate, In North America,
the high Rockies prevent the omshore esters
from penetrating far inland and the Britsh type of
climate is confined mainly to the cosslands of
British Columbia

In the southern hemisphere, the climate is ex
perienced in southern Chile, Tasmania and most
parts of New Zealand, particularly in South Island.
‘The surrounding large expanses of water have
increased the maritime nature of the climate here
Ge. 149).

Climate

“Temperature. The mean annual temperatures are
usually between 40°F and @PE, The warmest
month in London as illustrated in the temperature
‘raph of London Fig. 14a) is 63°F. and the oldest
month is just around 40°F, thus giving an annual
temperature range of only 24%E, which is come
paratively small or is latitude (SIN) Summers
ar in ac, never very warm. Monthly temperatures
fof over GS even in mid-summer are rae “Heat
unes” as they are popularly called (thet is à short
spl of warm summer days) are a welcome feature
in such cool temperate latitudes, where people
not often see enough of the sun, The climate
ideal for maximum comfort and mental alerness
People can work for long hours without fing
drowsy and lethargic as they do in the topics
“There appears tobe some direct relationship between
iat and Mas outa of wor: I no none
‘thatthe cool temperate regions are some of the most
advanced pats ofthe world, Winters are abnormally
mild, and no stations actually record mean January
temperatures below freezing-point in north-western
Europe. This is attributable to the warming effet

Fig. 147 Regions with Cool Temporato Western Margin Climate (is type).

‘unusual cold spells, caused by the invasion of cold
polar continental air from the interior, may hit the
Western margins for a number of weeks. The climate
‘of the maritime regions as a whole may be described
fs cquible with moderately warm sum
fairly mild winters

eis quite apparent from Fig. 148(b) of Hobart
Tasmania that the British type of climate in the
southern hemisphere is even more equable. Lack of
continental land masses in Tasmania, New Zealand
and southern Chile means that extremes of temp.
erature are not likely at al. Hobart has mid-summer
temperature of not more than 62°F while ts coldest
‘month in July (winter in the southern hemisphere)
is barely below 46°F. The annual temperature range
is reduced to only 16°F the
middle latitudes. This isin fact, the average figure
for all the maritime stations in the south
tinents where insularity overrides all other
The annual ranges of other southerly stations are
Dunedin 15°F, Christchurch 18°E, Valdivia 14°F
and Punta Arenas 17°F (the last two stations are
in southern Chile). The oceanie influences not only
keep the winters very mild but also keep the sunne
cool. Some geographers have described these
southerly islands as “the favoured isles’ which has
much truth init
Precipitation. The British type of climate has ado.
quate rainfall throughout the year with a tenden
towards a slight winter or autumn maximum from
cycloie sources, Since the rain-bearing winds come
from the west, the western marins have the heaviest
rainfll. The amount decreases eastwards with in-
creasing distance from the sea. Though both the
quoted stations London and Hobart have 24 inches
Of precipitation a year, the actual amount varies

quite considerably from place to place. Reich can
make great differences in the annual amount. For
example the western slopes of the Southern Alps of
South Island, New Zealand have as much as 200

ly, the Lake District
Of Britain has well over 100 inches in contrast 10
‘nly 24 inches in East Anl. I is therefore dificult
10 Say how much annual rainfall is typical of the
British type of climate. Perhaps, a welul guide
ul be to confine ourselves to lowland regions

À nomally have 20 10 40 inches a year eg. 23
in Paris, 28 inches in Dublin, 33 inches in
i wesen

ae four d nthe Brith climate type
ormaly only of short duration facts of Ihe
Comparativey mid weather But oer the highlands
Sor asthe Seandinaian Mountain and the Amen
tan Rockies snowfall et and dt he monada
Out at sc, glo are Frequent and can be dangerous
shipping. Spring is the diet and the most
[esos vi to es Olas Eos

n. This is followed by the lo

Sun-bathers, pienikers and. sightseers are out in
hemsehes. With the roar of

usty winds and the fall of “golden” leaves, autumn
pets tell. This type

is ushered in, and the cycle
fof climate with its four distinct seasons is something

that i conspicuously absent in the tropics

Natural Vegetation
The natural vegetation of this climatic type is
deciduous forest, The tres shed their leaves in

fold season, This is an adaptation for protecting
themselves against the winter snow and frost
Shedding begins in autumn, the “ul” season, during
which the leaves all and are scattered by the winds
The golden-brown leaves and the ‘naked? branches
present avery interesting scene, When they are in
leaf the deciduous tres have typical rounded out:
lines with thick trunks and out-spreading branches
tha yield valuable temperate hardwood (Fig. 149)
Some of the more common species include oak,
‘lm, ash, birch, beech, poplar, and hornbeam. In
the weiter areas grow willows, alder and aspen.
Eewhere are found other species, e. chest,

maple and lime,
Unlike the equatorial forests the deciduous tees
occur in pure stands and have greater lumbering
valve from u ei point of view. The open
nature of the forests with sparse undergrowth is
seal in logging operations. Easy penetration means
much cost can be ved in the movement of the logs
The deciduous hardwoods are excellent for both
fuel and industrial purposes In Tasmania, the

mperate evcalypts are ako extensively felled for
the lumbering industry. Higher up the mountains
in the Scandinavian highlands, the Rockies southern
Andes and the Southern Alps of New Zealand, the
deciduous tres are generally replaced by the conifers
which can survive a higher altitude, a lower
temperature and poorer soils

Economic Development

A very lange part of the deciduous woodlands have
been cleared for fuel, timber or agriculture. The
dense population necessitates the removal of the
lowland. forests, particularly for the plough. In
Britain thre is only 4 percent of the orginal forest
Jef. A large range of cereals fits and root crops
are raised, mainly for home consumption rather than
for export. North-West Europ, which includes some
of the most eronded pars of the globe, has litle sur
plus for export. Iti in fact, a net importer of food
{ops especialy wheat from almost all parts of the
hcatlnds for bresd-making and other food items.
“The region differs from many others in is unprece:
ented industrial advancement. The countries are
‘concerned in the production of machinery, chemicals,
textiles and other manufactured articles rather than
agriculture, fishing or Tumbering, though these
fctvities ate wel represented in some ofthe countries

Fishing ls partial import in Brin, Norway
and British Columbia. Sie de mme
aspect of india goer a
Sima grcer detal in Chapter 27, we hal dal ber
Si die agricultural development of the region.

1. Market gardening, ‘Though market gardening ls
aca hroughout the wor! ere tee à a
fr Ton, notre ee io MB

will be tremendous The city dwellers the factor
"workers and the cv serants who make up the bulk
of the urban population consume large quantities
Of fresh provisions daily and these must be provided
by local farmers if fresines of the produce is 10 be
ensured.

In north-western Europe intense market gr
ening is carried out in many specialized areas es.
the Vals of York and Evesham in the United King
dom where climatic, soil and other factors best suit
this form of agriculture. Farms are normally sl
located near large cies or industrial areas. Soils
whether sity, loamy or podzol, are carefully main
tained at a high degree of fet. Very selectivo
ferilzers are applied depending on the typeof crops
in culttation, Farming is carried out intensively,
aiming at high yield and maximum cash returns
A the crops are perishable, a good network of trans
port is indispensable. The produce such as lettuces,
cabbages, caulilowers tomatoes onions, peas and
fruits are seldom shipped but conveyed by high
speed conveyances such as trucks or vans. Perhaps
8 more appropriate term to use is truck farming
Which is commonly used inthe United States.

Ina few instances warmer weather oF better soils,
as in southwest England (Devon and Comal),
‘can also induce farmers to take to market gardening
despite their remoteness from the more populated
ists Early vegetables, early potatoes and tomar
toes reach London from the Canary Islands, the
Channel Islands, and from Brittany, in north
west France, Similarly, bulbs and flowers from the
Polderiands of the Netherlands and eggs, bacon and
Other dairy product from Denmark are sent to most
of the major industrial centres of Europe in almost
perfect condition for household consumption, The
‘horticultural industry in the Netherlands is so highly
specialized that Dutch tulips and bulbs are flown by
the K.LM. (Dutch Airins) 10 Rome, Paris, Zurich,

type of sol, the price of the, cereals an e
plana few frit tees x
pies keep poultry, mainly for eges and

Amongst the cereals, wheat is the most e
ofthe very dense population in north Europe
Atone time, some ofthe European countries (ance
Denmark and the Netherlands) used to be whos

exporters, bu
‘wheat-lands

the keen competition e
the New World forced most of the
their ine

farmers tod
table uses of their land st

dairying or an intensive form of mixed farmin
With the rise of industry, more arable farms are
devoured by factories and wheat is now a net import

item in Europe
Me next mest à
mixed fam & barley, The better quality bar is
Sol to the Breuer for beermaking or wiily
Aisling and is raised preferably in he die aca
Maling barley is ths grown in
Bein near the hop-rowing area (hops are also
used for beet) where rainfall Tess than 30 inches
On heavy sols or weiter regions, barley i grown
mainly as an animal fodder, sometimes mixed With
us as ‘dredge cor’. Both are raised ln cop
rotations with leguminoos cop (be
anda root ero (turnips or beet sugar.
‘The most important animals kept in the mined
farm are cate Norh-westem Europe was ri
nally the home of many world renowned calle
trends eg. Guernsy, Ayrshire and Frisian, which
ae estas dry cat or milk production. The
counties bordering the Noth Sea (Bin, Denmark,
the Netherlands) are some of the most advanced
ing counties where eile are kept on à scene
te and intensive bass Europeans drink more
milk than anybody ese exept the New Zealanders
In the United Kingdom, a person drinks almost a
Pint of milk a day! From milk, other important
‘diy products re derived, These are bute les
sam, and skied milk or case, à raw material
for making plastic, paper and drugs The temperate
ote marin ope of Simat no or
intense dairying. Cheese is a specinized product
of the Netherlands, rom Edam and Gouda From
comes high-quality butter, of which she

ranks with New Zealand as one of the wos
‘atest exportes In Devon and Cornwall clotted

5 oF clover)

‘An English farm, Notice the wellwwooded countryside Central Oca of Information London

ream is made, which is ess perishable than fresh
milk, It can be sent over longer journeys without
being contaminated. The Swiss have also mado
excellent uso of her alpin pastures for keeping dairy
resh milk is converted into various forms
ported
around the world for baby-feeding, confectionery,
{e-ceam and chocolate making
Besides dairying. some catle are kept as bee!
ue, eg. the Herford and Aberdeen Angus, but
‘hei numbers are very small in comparison with those
‘of Argentina or Australia, where meat production
is the primary concern, The high rate of beef
‘consumption in Europe (about 40 Iba year per head
‘of population in the United Kingdom) necessitates
largo imports of frozen and chilled bee. Inthe mixed
farms in Europe, farmers keep cattle also with à view

of enriching hei els wit he anal dung. The Pi
and pouty act as scavengers that fed on the ef
‘re fom root ops abt Gay peters TA
was, Denmark is able to export large quantities of
Bacon (am pigs that are fed onthe sumed mi, a
by-product of buttermaking. Fresh chickens” a
ffom the farms and more recent from large poly
yarl alo form part of the export products of
Denmark Sep are kept bth for woo! and matten,
Tn Bash Columbia, med farming is ested only
tothe most fvoure pars of the Westen lowlands,
the region being so mountainous aad EL forested
3. Sheep rear This is ell Heteloped se
ports of the Bi type of climate. Brain à the
Home of some of the bos known seep breed

Lesers Lincoln and Souhdamns wie are dia
purpose noted fr mutton as wel as wool, With the

ni us: RS

‘A sheep station ner Hawkes Bay, New Zealand NZ. High Commission Malaysia

eater pressure exerted on land by increased urbai-
“atin, indusralizaion and arte, sheep rain
ls being pused fuir and further into the es
{mourd areas The principal shop areas are on
Foothills, wellraned uplands, chalk and linen
‘arpland, and the Hight, sandy coasts. In Brits,
‘the major sheep areas are the Pennines, (Salut
sh Highlands (be Blckfac), the

(Cheviot), the Welsh Mountains

become instead
pedos animals
fire animal

| This is equally

rue of other north-western European sheep ares,
in which industilizstion has effectively altered the
Pattern of land use,

‘In the souther Sheep rearing is the
chef occupation of New Zealand, with its greatest
concentration in the Canterbury Plain, It has been
‘timated that for every New Zealander there are 20
sheep, Many factors have led to this unprecedented
‘growth during the past century including extensive
‘meadows, mild temperate climate, well-drained eve!
round, scenic animal breeding, and las, but most
‘ital, the development of refrigeration, which enables
frozen or chilled Canterbury lamb and Corriedale
‘mutton to reach every corner of the globe. Though
New Zealand has only 4 per cent of the worlds
Sheep population, it accounts for two-thirds of the
‘world’ mutton exports and one sixth of world woo!
‘exports In Tasmania and southern Chile, sheep

4. Other agricultural activities, Apart from market
gardening and mixed farming which have ben singed
out for greater individual treatment, the Bish type
of climate also supports a number of other important
ropa. Amongst the food crops, feature
inently in the domestic economy of the cool
ns I à th supp

n supple

menting wheat or bread for milions of people hi
people In

cereals and can be cultivated over a wide range of
climate and soil types. But normally a cooler and
more northerly latitude is preferred because the crop
wil be less prone to the attack of “big, a virus

Peru and Bol

or rom the Andean sats of

in the sixteenth century, potato
growing has spread far and wide in Europe. Today
“almost two-thirds of the words annual production
‘of potatoes comes from Europe, of which Poland,

Germany, France and Unite
major producers
substitute

Kingdom are the
Besides ls principal

bread, large quantities of potatoes
fare also consumed as

her inertie cop that is found almost
chic in northoeser Europe (nchding Euro
pean USSR) and pats of USA. is bet sugar
The ned for sch a Gop vas eel el during the
Napoleon Wars around 180 when military lok
ad caused a ser of sugar. High pres of
imported topical sugar (rm cate sug) rove mary
fovernmens ofthe tempera land 1 ak serous
About the val importance of scurin a certain
amount of suc) ir sugar requirente
The ist es soga factory in Europe wa subis
in BD Farmer were en SUIS (id or alone
ce) o indac he o devote a es par of hi
farm tothe cop. Since then Hub has become
an inal pt of muy, ae ams 1

Im er on special bet farms for ssh sls or
in conjunction with cls in crop rotten, The
tects shed fr sugar andthe sen ops ar sed
35 animal oder The cop ire Bi te
armer and di ist of Briain and in mainland
Europe. The highest sugar yield obtained hen
the autumn i both dy and sunny Aes 0
tow the cp in he colder north or the weiter West.
fives far ben rar uns up in some

East Ar

QUESTIONS AND EXERCISES

Bi
cribea type ol climate
Westrls come all the year

following statements attempt 10 des

‘there i a tendency towards an a
for winter maximum of rainfall. ght
snow falls in winter....ports are never
frozen...but frosts do occur on cold

nights. the seasons are very distinct
and the climate is very favourable for
maximum human output

(a) Name the type of climate that it
describes.

(0) Locate with the aid of a sketch map a
region where such a type of climate is
bes represented

(Explain why such a type of climate is
deal for human habitation,

2. Deseribe and explain with the ad of sketch

maps the essential différences between the

various climatic types found within the cool

temperate zone

3. (a) What are the characteristic features
of temperate deciduous forest?

(0) Name the various species of deciduous
forests and account for some of their
industrial ses

(9) Explain why there is comparatively

le of the orginal forest et
4, Write a geographical account of any three
of the following economic activi.

(@) mixed farming

(9) beet sugar cultivation

(e) cool temperate orchard farming

(a) sheep rating

(e). woollen textile industry

5. Give an explanatory account of any imo of
ihe following.

(a) The Netherlands is a major exporter
of butter and cheese

(0) Sheep outnumber the population of
New Zealand by 201

(©) No country produces and exports

@

(Siberian) Climate
Distribution

‘The Cool Temperate Continental (Siberian) Cl

mate is experienced only inthe northern hemisphere

here the continents within the high latitudes have à

“broad este spread (Fig 150, On is poleward

+d, it meres ito the Artic tundra of Canada and

| Eurasia at around the Arte Circle. Souhward,

‘the climate becomes less severe and fades into the
tempera Steppe climate delt wth in Chapter 19.

The predominant vegetation of this Siberian or

| sabra rc” type of climate is evergreen coniferous

| fost I streches In a grat, continuous belt across

“America, Europe and Asia. The greatest

le band of the coniferous forest the tiga (a

“word for coniferous forest) in Siberia, In

pS the countries that have a similar ype of

forest are mainly in northern Europ,

Finland. There are small amounts of

forest, due to high alte, in

y, Svizerand, Austria and other

Chapter 23 The Cool Temperate Continental

The Siberian Climate is conspicuously absent iy
the southern hemisphere because of the ramones.
‘ofthe southern continents inthe high latitudes The
Strong oceanic influence reduces the severity of the
inter and coniferous forests are found only on the
‘mountainous uplands of southern Chile, New Zea.
land, Tasmania and south-cast Australia,

Climate

‘Temperature. The climate of the Siberian type is
characterized by a bitterly cold winter of tong
duration, and a cool brie? summer. Spring and
Autumn are merely bref transitional periods. The
is of SE forthe warmest mont ons the
poleward boundary of the Siberian climate and
the winter months are always below freezing. The
Stations chosen to illustrate this type of climate are
‘Moscow, in continental Europe and Churchill, in
northern Canada, bordering Hudson Bay. The col
dest month in Moscow is January with 12°F (20°
below freezing point). The warmest month July)
is as high as 66°F; thus thee is an annual range of
SW, which is common in the Siberian type of

temperature
range for Church

is even higher, reaching 739
ICI in January and SA’ in Ju), This due to
the more northerly position of. Churchill, The
extremes of temperature ar in Siberia th

itis often refered 10 as the ‘coll pole ofthe earth
Some of the lowest temperatures in the world are
recorded in Verkhoyansk (68°N. 113°E. und only
330 fet in altitude) where -90°F: was once recorded
This i, infact, 170 than Kuala Lumpur!
Iv is almost unimaginable In North America, the
extremes are les severe, because of the continents
lesser eustenst stretch. The lowest. mid-winter
means in the cold Mackenzie Valley are not louer
than 70°F

With such low temperatures in the cold season,
heavy snowfall can be expected. Frosts oocur as
early as August and by September lakes and ponds
are already ice-bound. All over Russia, neatly
all the rivers are frozen. The number of days in
Which the rivers are frozen increases from south 10
north. In normal years, the Volga i icecovered
for about 150 days, while those further north (eg.
the lower courses of the Ob, Lena and Yenisey) are
icecovered for more than 210 days or 7 months!
'Oscasionally cold, northerly polar winds such as the
blizards of Canada and buran of Eurasia blow
violently at $0 muph. or more and ata temperature
of SO'E. below freezing point. The powdery snow
flakes are blown around inthe loner atmosphere and
visibility is greatly reduced. Conditions are so
unbearable that Siberia i very sparsely populated but
itis gradually being developed.

Precipitation, The interiors of the Eurasian con
tinent are so remote from maritime influence that
annual precipitation cannot be high. Generally
speaking, a total of 1510 25 inches is typical of the
annual preciitaion of this sub-Aretc type of
climate. It is quite well distributed. throughout
the year, with Summer maximum from conveetional
‘ain when the continental interiors are greatly heated

(miesunmer temperatures of 60° to 75°F. are aut
‘sual and the maximum recorded in Siberia is areal
Surprise. 102°) In winter the pretation isin

‘Annual precipitation: 21 inches
Annual temperature ange: SE (65-12)
Fig. 151 (0) Siberian Climate in Eurasia

RT

CELLES

T

‘ona precision:
‚Annual temperature

The total precipitaion of the Siberian climate
is determined by such factors as altitude
Proximity to the poles, amount

fluences by Wiesteris, (on western parts of
tinent), temperate monsoons (on the casera
Of continents) and the penetration o
European USSR, usualy has m

of annual precipitation because of some on-coming
Westrlies and the periodic penetration of cyclones
Eastern Siberia alo has over 20 inches, being mont
nod by ihe SE, Monsoon from the Pacihe Osan
Central Siberia and Canada av

due 0 their and lack of sea influence
Polewards and southwards, the amount again de
eases to only 12 inches or less. The cold dy ar

Of the north is incapable of holding moisture, and
in he south are the semiarid steppes

Snow falls nearly everywhere in USSR. in the
Jong, cold winter. The amount varies from place
16 place. It is heaviest in the northem tundra and
in the Siberian aia, where a thickness of several
fet is common, Permanent snowflds like thee
of the Alps or the Himalayas are absent, because
any accumulation of snow is melted with the rotura
‘of spring and the warm summer, Frozen river are
awed, causing arise in the water level and exten
sive Moods occur. The lower courses of the Ob: Leng
and Yenisey are marshy and On the
other hand, the presence of a thick mantle of snow
is not without its besings Snow is a poor conductor
Of heat and protects the ground from the seme
old above, which may be as much as 30° 50°F
‚older! It also provides moisture for the vegetation
When the snow melts in spring. When the ground
is ploughed and the leached, acidic podzolic sol

is improved, the continental interiors of the conifer
ous forest belt are capable of supporting some
agriculture.

"ig: 152 Diagram t show changes in vegetation in joumey Polewards from the Tiga Zone

Natural Vegetation

belts of Eurasia and North A i
‘other branches of the chemical industry The mos
Bietet softwood producers are USSR. Usa
Canada and the Fenoscandian countries (Flags
Norway and Sweden). In the production of woot
pulp (by both chemical and mechanical metho,
the USA. isthe leader. But in the eld of no

Canada has outstripped all other producers moo

ing for almost halt of the world’ to
7 Or total annual pr

The more accessible coniferous, fp
have reached the limit of production but the rea
vel inaccessible taiga of Siberia will remain tho

richest reserve oft

5, €. white pine, red pine, Scots p
= lodgepole pine
as Arnd balsam fir

4

Their presence in

es area great advan
forest exploitation

Coniferous forests

1 Coniferous forests are of moderate density. Un
like the equatorial rain forests which are luxuriant
and contain tres of various heights the coniferous
forests are more uniform and grow straight and tal,
‘upto height of about 100 fect. Where the poleward
limit of tee growth i approached the tees are widely
spaced, and give way to tundra vegetation (Fig. 152).

Coniferous forests onthe easter Rockies, Alberts, Canada Matinal Fi Board of Canada

Spl ee
Te e
ee
OURS
en
nt

of he cons fete ae poor. They re cs
Sly leche and voy eld The ergs lens
Provide ide etal fr humus formation amd ie
Fue of decompasiin of be ete mel ln à
sión of such low temperature don Al hee
fos re Seen ote ah of much E
growth, Absne of dit unie an the shor
Sun of immer a ole cs ae
toa u undergrowth, bu whee tes ar wi
Spaced near the rc, ath and tun plans
lve the inet ground
sles the continental interiors of the higher
tados omita fot ate found in tet
late rios wherever lide roles the tem
tre The confers arin fit, the dominant
teat al moutons dit ow ete
erste and topical countries But on tem. sep
{Tops where al ae mat r noc ere
den amount

Economie Development
‘The coniferous forest regions of the northern
emiphere are comparatively lite developed. In
m

sie son nié

Canada, castern Europe and Asiatic Rosi, lange
tracts of coniferous forests are sil untouched. Only
in the more accesible areas are the forts clated
for lumbering
lar and spruce are felled and transported to the
Sawmills fr the extraction of temperate sof-woods
There i ite agriculture, as few crops can survie in
the sub-Arteelimate of thee northerly lands. The
Jong, cold winter the fozen soils and ıhe low mean
Annual temperate thouehout the year exclude all
but the hardest crops. Only inthe more sheltered
valleys and the lands bordering the steppes are some
sercals (barley, oats, ve) and root crops (potatoes)
raised for local needs: Many of the Sumoyeds and
Yakuts of Siberia and some Canadians ar engaged
in hunting, trapping and fishing. We shall deal
with two of the major activi in greater detail
1. Trapping. Many. furbearing animals. inhabit
(he northerl lands of Canada and Eurasia, Wherever
the cold is hoenos, the quality and thickness of the
fur aso increases Consequently, the most severe
inter produce the finest furs which fetch the
hist prices In Canada trappers and hunters
armed with modem automatic is, reside in log
abs in the midst of the coniferous forest to track
down these animals Their Ines are hard and
| prsariou at times, but the rears are great if the
“haness are good. Muskrat, ermine, mink, and
ive fo are the most important fur-bearing animals
sought after in Canada. The Hudson Bay Company
as many stations seatiered in the northern regions
to trade in furs with the Canadian trappers and
hunters. To ensure a more regular supply of furs
‘many fur farms have been established in Canada,
“Animals such as the silver fox and ermine are kept
Je ep a el nen de fr och à
table stage. They fetch high prices in sophis
‘sed ces Ie Nev York, London Pas Kane
nd Za, vir pls e prod sa
‚für coats and women’s handbags. In Siberia
2 animals are trapped. These are
bean, sables,
furs

The various species of pine. ti

‘constructional woods
(0) Paper and pulp industry. Timbe a
by both chemical and mechanical means to moh
wood pulp the raw material for paper i
newsprint. The development of the printing industry
has made paper and pulp indi a
and USA, are leading producers of the worlds
supplies of newsprint and wood pulp respeta

ck uss a power.saw to cut up a
‘Quebec, Canada National Fm Board of Cs

(9 Aa tl Les tan a quan the vor
oo. le lim a fil: ease is, nal
Ds er re ali Ts cca ino
ele OÙ the ory harias ae Da
1a Jud, parla opa! Bancada she be
sir sl a

(@) Av an nial antral, Tinber as
1 whe range of usu In Sande cos ora
major export em From oie feet cu
tay tinker ed for malig furs woo
an

ct le ner muy ehem ps

ara re Aid rch as ton petting var
_nishes, paints, dyes, liquid resins, wood-aleohols, di
nens come

Logs are poled in
‘of the coniferous forests

is characterize by th

1. The conifers are limited in s
And fr are the most important i

while larch is more predominant in the warmer south

They occur in homogeneous groups and not mixed as

orests. This not only saves time

chances the commercial valve

es. Pine, spruce
he northern forests,

and cost, but also
of the elle timber:
2. In these northerly a
impossible and lumbering replaces farming in the
continental interiors. Even where rops are cul

‘ate, farmers are idle in the winter months and ean
supplement ther income by doing part-time lumber-
ing in the forests, they do in most parts of Europe.

3. Lumbering is normally carried out in the winter
hen the sup eeases to flow. This makes fling
‘uch simpler. The snow-covered ground also makes
logging and haulage a relatively easy job. The
logs are dragged to the rivers and float to the se

ropical

mills downstream when the rivers thaw in spi

"This has greatly assisted the development of the
lumbering industry in eastern Canada and Sweden.
Unfortunately, over the greater part of Siberia.
all the rivers drain polewards into the Arctic Ocean
which is frozen for three-quarters of the year and
here are few saemill there. With the use of
tte Northern Sea Route, which links Murmansk and
Vladivostok via the Arctic Osean, development is
increasing. Cheap ity for diving the
‘semis is harnessed in the mountainows uplands
fof North America and Europe and has paty assisted
the lumbering industry

factory from the Ottawa river, Quebec, Canada National Film Board of Canada,

QUESTIONS AND EXERCISES

1. Compare and contrast deciduous forests and
coniferous forests in respect ofthe following

(a) distribution

(6) vegetational characterises

(©) climatic intuenee

(4) economie development
2. Distinguish between hardwoods and sof
‘woods, What industrial uses are made of them?
Account for thet large scale production for
‘export in ny one country

3. Give a reasoned account of any tree of the
Following

(a) The annual
Moscow i $4

(0) The annual precipitation of Leningrad
{snot more than 19 inches.

(0 The lower courses of the Siberian
rivers are frozen for as long as seven
‘months

&) One ofthe coldest spots on the lobe is
Verkhoyansk with a record lowest
temperature of 90°F

temperature range of

44. What meant by

(a) the ga

(0) the veld

(6) theselvas
{Account forthe distribution and characteristics of any
‘wo of them.
5. Describe the role played by fret produet inthe |
‘economy of ether Canada or Sweden,

Sa RES

Chapter 24 The Cool Temperate Eastern Margin (Laurentian)

Distribution
The Cool Temperate Eastern Margin (Laurentian)
(Climate i an intermediate type of climate between
the British and the Siberian type of climate. It has
features of both the maritime and the continental
climates It is apparent from Fig. 153 that the
Laurentian type of climate is found only in two
regions One is north-<astern North America, in-
sluding eastern Canada, northeast USA. (ie
‘Maritime Provinces and the New England stats),
and Newfoundland. This may be refered to as the
North Amerian region. The other region is the
‘astern coastlands of Asia, including eastern Siberia,
North China, Manchuria, Korea and northern Japan
maybe referred toas the Asiati region,

Inthe southern hemisphere, this climate type is
absent because only a small section of the southern
ontinents extends south of the latitude of 408.
‘The only possible location is in eastern Patagonia,
South of Bahia Blanca (at 39°S) to Tierra del Fuego
‘at. $48), But the climatic barrier of the southern
Andes is so complet, that the Wester hardly
‘ever each Patagonia. The region is subjected to

aridity rather than continental

Pian $ mo more than 10 inches vo tar FR
finshudow deer Elovier in the donne
hemes the mat so able and Ihe nm

influence is so profound that neither the continental
‘nor the caster margin type of climate exist

Climate
The Laurentian type of climate has cold, dry
Winters and warm, wet summers. Winter temper,
atures may be well blow freezing-point and show
falls to quite a depth. Summers are as warm as the
tropes (10° 80°F.) and if it were not forthe cooling
effets of the offshore cold currents from the Arctic
the summer might be even hotter. Though tain
falls throughout the year, there isa distinct summer
maximum from the easterly winds from the oceans,
(Of the annual precipitation of 30 to 60 inches, two.
thirds come in the summer. Winter is dry and cold,
because the winds are dry Westelies that blow out
{fom the continental interiors. We shall now examine
in coser detail the variations of the Laurentian type

ELZIIER]

Alttude: 216
Annual precpitaon: 41 inches

Annual temperature tango: AE (41-31)
Fig. 154(a) Laurentian type of Climate in North

America

ELLE

American region is is unlformity se proto
(about 3 to 4 inches monthly) with a hte summer
maximum. New York in Fig, 1549) has an anual
Precipitation of 41 inches with the wettest months
in July and August (42 inches cach). No month is
really dy, and the driest month, November, has 25
inches of rain, This uniformity of precipitation
is largely due to the Atlantic influence and that of
the Great Lakes The warm Gui Stream increases
the moisture content of easterly wind from the open
Atlantic, The prevalling Weserlis which penetrate
across the Rockies carry depresions over the Great
Lakes to the New England states These winds this
promote wet conditions especially in winter which
are vital for the agricultural activites of mort
sistem North America. The mectng of the warm
Gulf Stream and the cold Labrador Current on
coastal waters off Newfoundland produces dense
mist and fog and gives rise to much precipitation,
St. John's its capital has as much as $4 inches of
annual precipitation. It i said that Newfoundland
experiences more dis thin any other part of
the world,

Monsoon type in India, where the whole year’s
‘nfl is concentrated in the three summer months
‘The mountainous interior of China has such pro
‘Bounced continental effects thatthe intense heating

Summer creates a region of extreme low pressure
| and moistureladen winds from the Pacific Ocean
and the Sea of Japan blow in as the South-East
‘Monsoon. The Laurentian type of climate here
is often described as the Cool Temperate Monsoon
Climate. It has a very long, cold winter and a
big annual range of temperature, The July mean for
Peking is 79°E while that of January is only 24°F
‘The temperature range is therefore more than SS.
‘The dry, cold wind that Blows out from the heart
‘of Asia in winter caries fine, yellowish dust and
posits it as a thick mantle of loess in Shans,
‘Shensi and other neighbouring provinces atthe bend
of the Hwang Ho. Much of the winter precipitation
in northern China, Korea and Hokkaido, Japan, is
in the form of snow. In the mountainous districts,
‘thesnow piles toa depth of 510 10 feet.

currents. It receives adequate rinfall from both
the South-East Monsoon in summer and the North.
West Monsoon in winter: The later isthe dry, cold

speaking, the forest tend to be coniferous
the SON, parallel of latitude. The ino

Tength and severity of the winter excludes fürs
that are not adaptable to cold conditions. In un
Asiatic region (eastern Siberia and Korea), the
coniferous forests ar, in fact, a continuation ef the
reat coniferous belt of the tiga, Lumbering

always been a major oecupatio

la isa leading
export item. Much of the original coniferous fore
‘of fi spruce and larch have been cleared as a result
‘of lumbering rather than agriculture, Eastern
Canada, along the banks of the St. Lawrence River
fs the heart of the Canadian timber and wood pulp
indus

South of latitude SON, the coniferous forests
gie way 10 deciduous forests Oak, beech, maple
and birch are the principal res. Like their counter
parts on the western margins, the deciduous forests
are fairly open, A long growing season of over six
months and an adequate supply of moisture from
‘maritime sourees encourage rapid growth of ferns
and other temperate undergrowth. The occurrence
of tres in almost pure stands, and the predominance
‘of only a handful of speci

they
ave been extensively felled for the extraction of
femperate hardwood. In many parts of Manchuria,
Korea and Japan, the forests have made way for the
Plough. Both food and cash erops are raised. In
‘Canada, due 10 the greater reserves of coniferous
softwoods and their overriding importance in indus
trial uses the annual production of deciduous
hardwood is much less significa.

Economic Development
Lumberng and is associate timber paper and pulp
industries are the most important economic under
taking. (Details of lumbering have already been dealt
within Chapter 2).

Agriculture sess important in view of the severity
of ‘the winter

and is long duration. Fortunately
maritime influence and the heavy rainfall enable

|
|
|

“American region, arable farming is not cari out
On à sizable sale, xe inte mor noe los
likes, Famers are engiged in day farming ay
canton an, in mild martine ares fat growing
“he ferile Annapoli vay in Nove Scotia he
worlds most renowned region for apples. Fishing
iS however, the most oustanding eonom activity
ofthe Laurentian climate regions.

rll mer ans
and New England
This is one of

ives

A fisting setlementin Newfoundland. Much o the fish is dried for export National Film Board of Canada

ee
ee
rawlers, dragging large conical-shaped nets, and
PL ne
De...
LT ee
rn
Bere
eo...
en
eo...

spe and very client In &
isa growing problem. The Unite States gover:
ment and intermaona ing boi are non co
templating ict measures tn fsb conservation if
this major sours of protein fod i tobe sustained
Real spp in th years to come

Filing off Japan. In the nose Pasi
surrounding the lands of Japan, is another major
fing rea of the word, Nowhere ds inthe
world athe o many people nga in fing as in
this prof the north Paste The mountings
autre of Japan and pars ol mainland easter Aia
ine den many tok a lo fo thee

sui of met (er le pasture In pen
for livestock farming of any Kind) and religous
reasons have popular sh ste pina tem of
die and the che! pros food ofthe Japanese
And he Chinese aswell, Large qua offhand
fh products are cher camed or pressed for
export to neighbouring counties, The Japanese
ko make use of fish wastes fh mel and sones
a eli in thee farma Japan e on ofthe few
Sout dat hs uam fo seabed clan

ums that are submerged in water

a ers chal pedo nd

Another interesting aspect of Japanese sine
is pet tue The divers of southern Japan die
down int the coastal waters und bring 10 hr sara

shellfish called and extract the highly

f ments The lining ofthe

led mother-of-pearl is used for the

ns, and other decorative

Pearls in oysters are difficult

© numbers, the Japanese have begun

to Breed the young oysters By injecting tiny ‘seeds

ade to secrete the peal

cumulates to form ‘cultured pearls
collected and exported,

AS natur

These a

The Japanese interest in fishing is not confined to
their own territorial waters, they venture far and wide
10 the Arctic, Antaretie and the Atlantic waters.
Large whaling lots complete with processing plants
“and experienced crews stay out in the open seas and
return only occasionally. for refuelin
istment of fresh
accounts for a sixth of the world’ total
caught. She is the worlds greatest fishing nation
today. Her active participation in international
fishing enterprises and her advanced fishing techni-
ques speak well of her relentless drive to make good
from the seas what she lacks on land

Let us find out why this is possible
1. Japan isnot well endowed with natural resources
for as much as 80 per cent of her land is classed
‘non-agricultural’. She has to take to the sea if she
wants to survive. This has compelled the people to
develop the seas, and fishing has for centuries been
the traditional occupation of many coastal Japanese.
2. The continental shelves around the islands of
Japan are rich in plankton, due to the meeting of the
warm Kuroshio and the cold Oyashio eurrents and
provide excellent breeding grounds for all kinds of
fish including herring, cod, mackerel, bonito, salmon,
sardine and tuna, as Wel as crabs and lobsters
3. The indented coastline of Japan, provides shel-
tered fishing. ports, calm waters and safe landing

‘cultured pearl frm in Jap

places, ideal forthe fishing industry In Hokkaido,
Where the Laurentian type of climate is too cold for
€ agriculture ishing takes first place. Hakodate
and Kushiro are large fishing ports, complete with
ration faci
44. Lack of lowlands and pastures means that only a
few animals can be kept to supply meat and other
protein food. Fish, in all its varied forms, fresh,
canned, dried, frozen, and in the form of sh pases,
fish sauce and spiced condiments takes the place of
meat as Japans primary source of protein food
There is great demand for it loclly and for export
to other cast Asiatic neighbours which lack the tech
niques of large scale commercial fishing
5. The Japanese fishermen began with small fishing
boats, using nets taps and lines. With the progress
made in industries, ishing has also become more
Scientific, aiming at heavy hauls, high returns and
economy of time, effort and money. Though thre
(quarters of the fishermen practise offshore pelagic
fishing ether fulltime or part-time, in small boats
most of the commercial deepsea demersal sing
is now highly mechanized. Powered trawlers and
modern reirigeration plants backed by sound finan-
cial organizations have greatly increased the annual
fish yield, Japan is now not only a major producer
and exporter of fish and marine products, ut also a
‘entre for marine and fishing research,

QUESTIONS AND EXERCISES

1. (a) Locate on a world map the extent of
the Cool Temperate Eastern Margin (Lauren-
tian) Climate.

(©) Explain why this ype of climate is
confined tothe northern hemisphere

(©) Describeits climate.

2. Compare and contrast the climate of any
‘no ofthe following pairs of areas

(a), Laurentian Climate inthe North Amer
can region and the Asiatic region.

(6), Tropicalmonsoon Climateof Indi and
the Warm Temperate Eastern Margin (China.
type) Climate in S China.

(0). Fishing in Japan.
(6) Soya bean culation in Manchuria,
(9, Fritgrowinginthe Martine Provinces
of Canada

5. The following statistics are a guide to four
diferent types of climate in the northern

(a) Name the type of climate that each
of them represents,

(0), Locate a probable station foreach

(9) For any two of them describe their
imate characteristics,

“Annual

Fara Month of max. rain

temp.renge Rainfall,
SE 96 Apriland October
ASE e June, July, August
OE = Irregular
AE ar July, August, September

Chapter 25 The Arctic or Polar Climate

Distribution
‘The polar type of climate and vegetation is found
mainly north of the Arctic Cirle in the northern
hemisphere. The ice-caps are confined to Greenland
and to the highlands of these highdattude regions,
where the ground is permanently snow-covered
‘The lowlands, with a few months ie frs have tundra
vegetation. They include the coastal strip of Green
land, the barren grounds of northern Canada and
Alaska and the Arctic seaboard of Eurasia. (Fig.
156), In the southern hemisphere, the virtually
uninhabited continent of Antarctica isthe greatest
Single stretch of ice-cap where the layers of permanent
ice areas thick as 10,000 fet,

Climate

‘Temperature. The polar climate is characterized
by a very low mean annual temperature and its
‘warmest month in June seldom rises to more than
SO'E. In midavinter (January) temperatures are as
low as -39'R and much colder in the interior.
‘Normally not more than four months have tempe-
‘atures above freezing-point! Winters are long and

Fig. 156 Ico Cap and Tundra

very severe: summers are cool and brief Within
the Arctic and Antarctic Circles, there are weeks
‘of continuous darkness. At the North Poe, here
are six months without light in winter Despite the
long duration of sunshine in summer, when the sun
does not set, temperatures remain low because the
sun slow in the sky and much of the warmth of its
faint rays is ciber reflected by the ground snow,
or used up in melting the ice. I has litle power
Jet to rase the air temperature. Water in the soil
is frozen to great depths and the summer heat can
‘only thaw the upper si inches ofthe soil. The ground
remains solidly frozen for all but four months,
inaccesible 10 plants Frost occurs at any time and
blizzrds, reaching a velocity of 130 miles an hour
are not infrequent. They can be very hazardous
for the polar inhabitants. In coastal districts where
armer water meets col land tick fogs may develop.
‘They last or days, and in many instances it is not
possible to se for more than a few feet.
Precipitatio. Precipitation is manly inthe form.
of snow, filing in winter and being drifted about

Tundra vegetation
In such an adverse environment as the tundra, few
plants survive. The greatest inhibiting’ factors
the regions With a growing
season of es than three months and the ware
month not exceeding FF. (he tresurvival line)
there are no trees in the tundra, Such an em

ment can support only the lowest form of vegetation
mosss lichens and sedges in the unde
is usually poor asthe subsoils permanently frozen
Ponds and marshes and waterloggod areas are found

in hollows.
TruAn Tun GONG In the more shelter stunted
war willows and undersized alders sru

E meagre existence. Climatic conditions along the

coastal lowlands are a lite more favourable. Here
are found some hardy grasses and the reindeer moss

Place: Upernavik, Greenland (720, 56W)
ee ) hich provide the only pasturago forthe herbivorous
Behe ee estes laches animals like reindeer In the brief summer, when

[temperature range: 92 ($417) the snows melt and the days are warmer and longer

bem-bearing bushes and Arctic lowers bloom
‘Though shortlved, they brighten the monotonous
tundra landscape into Arc In the
Summer, the tundra is fl of activities. Birds migrate
‘orth o prey on the numerous insets which emerge
When the snow thaws. Mammals like the wolves,
foxes, musicox, Arctic hare and lemmings also lve
in tundra regions,

ring lizards Snow a wih li, i
fal her as ee crystals or large, amulgamated
Sov tte Arne 1) ne oh ee
Make inch of rain, precipitation in polar regions
Lo be lg, not more than 12 inches

a eat. Comeetional rainfalls generally absent
because of the low rate of evaporation and the lack
in the old polar ar Tere is normaly

he precipitan is then

Human Activities
Human atts of he tundra are target com
fine (0 the eos. Wher plateaus and monas
ince te lud it unnkablab or tho are
ermanentysnowcoveret, The fen’ people who
{hein he tne ve aser nomad He nd hc
tap em a mamen
> ed, Horte Canada and Ala
Ine the Eakin numbeang Is than 28.00 tly.
They wed to Tne as busta, bes and oo
ati but in eel years mor and more ol hem
ate sing in permanent huts The Polar timos
around Thule in nontewest Grenland i
uncertain life, not very much different from
“he seasonal changes in lime

nomadic way of life. During winter
Pact igloos and in summer when
they pith portable tents of

seams. Their fod is derived

the Europcans, the way of life of the Eskimos has
undergone tremendous changes. Coastal. villages
have permanent wooden houses complete with
modern facilites; speed-boats are replacing mil

Kayaks Deadly res instead of traditional harpoons

are used to track down animals and seals. Fur
bearing animals eared on a commercial
scale and fishing, 100, is being commercialized. In
Some more accesible parts of Canada and Alaska,
school hive been established and the Eskimo
children are being taught the skills which will allow
them 10 ft into the modern way of life

Ihe Eurasian tundra are other nomadic tribes

such as the Lapps of northern Finland and Scandi
via, the Samoyeds of Siberia (rom the Ural Moun:
tains and the Yenisey basi), the Yakuts from the
Lena basin, and the Koryaks and Chuckchi of
north-eastern Asia, They wander with their herds
of across the Eurasian tundra where there
are pastures. Many of them have taken to a more
settled life In the USSR. have been
‘established for rising reindeer and for breeding
fur-bearing animals

‘The Importance and Recent Development
of the Arctic Region

The Arctic region, once regarded as completely
sees, now of some economie importance. Apart
from the efforts of the various governments in asis
ing the advancement of the Arte inhabitants the
Eskimos, Läpps, Samoyeds te, new settlements
have sprung up because ofthe discovery of minerals

is mined in Alaska, nickel near Petsamo,

USSR um in the Kenai Peninsula, Alaska

4 copper at the Rankin Inlet, Canada. Coal has
een mined in Spitsbergen for a longtime and also
in Alaska. With the declining reserves of iron ore

around Lake Superior, the Great Lakes industrial
sare using more and more iron from lage
re deposits in Labrador, New

have been constructed to bring the ores to the SL
Lawrence River for subsequent shipment to the
major industrial districts Rich deposits of iron
res at Kiruna and Gallivare in Sweden have made
it possible for Sweden 10 enjoy a prosperous export
trade in iron and steel and other metallurgical

the establishment of ports on the Arctic
seaboard of Eurasia it is now possible to ship timber
and fur from Siberia. Though the ports Such as.
Tarka at the mouth of the Yensey, are not ice
free, modem o keep the passage open
most of the time. On the Arctic lowlands where the
growing season is Fengthened by warm currents or
jeher temperatures experiments have been carried
‘out to devise varieties of hardy cereals for local
reeds. It may not be long before the tundra is
brought under greater agricultural, especially past-
oral, use. The healthy air and its preservative
‘qualities (iis practically germ-fre) are factors worth
‘consideration for. future colonization. Scientist
meteorologists and explorers have lived in the Artic
and Antarctica, making studies of their geology,
‘weather conditions plant and animal Tie, that will
be of great significance In years to come

‘The borderlands between the Taiga and th tundra Elizabeth Mayor

“any one of them explain how the features are
‘elated tothe climate ofthe area

2, Statistics of rainfall and temperature for
three towns are given below. For any mo of
them.
(a), State their season of maximum rainfall
(b) Name the typeof climate
(©) Suggest a possible location of the town
(@)_ Describe their climatic rhythm.

Range/Total
100 O D

A
57 4 71 76 76 70 62 53 4% 39
26 22 18 07 10 25 50 44 39 327

BS 4 NS 24 25 14 1049
06 06 05 09 01 11 11 11 05 91
ss

5 55 55 55 65 55 55 510
46 15 11 22 26 39 40 36423

4, Explain briefly any four of the folowing
ferms connected with the Arctic climate and the
‘tundra vegetation:
blizzards, permafrost, midnight sun, ice
ap, snow-blindness, kayaks, international
decp-freee.

Make a comparative study of the Polar
SGrealnd and the Orang Asi
ee,
obtain their food.

For ach ofthe uo you have chosen, describe the chief feature of the vegetation and show how they ane eae io
the geographica characteristics ofthe region. (1962)
4. With the aid of sketch maps locate examples of two ofthe following:

(4) An evergreen forest in a hot region,

(0) A deciduous temperate forest

(©) A region of tundra.

For ach one you choos, describe the chie features ofthe vegetation and show how these are related tothe ciate
of the area. (1961)

5. (2) Drawasketch map of onemajorland area, which extends in latitude from the equator tat east 25° North
(035 South, On the sketch map, mark distinctively and name three major areas of different natural

(6) Describe the important features of the natural vegetation inthe areas marked on the sketch map. (1960)
6 Mean Monthly Rainfall in Inches
Tom Lat Log JF M A M J I As O N D ml

Darwin 12°S. 13I°E. 152 123 100 38 06 01 00 02 OS 20 47 94 587
Adelaide 395. LWE. 08 07 10 18 27 30 26 26 21 17 LI 10 24
Alice 25'S IE 17 13 11 04 06 05 03 03 03 03 12 15 99

Springs

For each town:
(a) Describe briefly the main features of its rainfall
(0) Suggest reasons forthe amount and distribution of the rainfall (1967)

7. Records of temperature and rainfall for tree towns are given below For each:
(a) write a description ofthe temperature and ranfs
(0) name the typeof climate, give reasons for your answer,
(©) locate one area in the world wher his typeof climate occurs (1963)

A. (Altitude 9,350.)

JU FUUM AM NS Agee ta en
E SS SSS) SSS 5) Ba
Rainfal(in) 32 39 48 70 46 15 LI 22 26 39 40 36

B. (Alitude30n)
Temp (F) # 4 # #
Rainfall Gin) 55
©. (Aude son)
Temp.(F) 7% m 8
Rain) 15

Chai snes.

solo 33

nts 63

Clpuès: 100-105, Clasitcaion or
100-102 Caras 98 Funnel fy

“Ground cloud", 104; Cum

108; Status 108

Cloudicover, 10: forms
106;-1ype, 100

Cloudiness 70,116

‘Coastal landforms, 72-78

‘Coastal plain, se under Plains

Cocoa, 119

Cols 126

Compressed (ai, 112

‘Compressional forces,

‘Condensation, 100, 108

Conduction, 105

Conduit, 22

‘Conglomerate, 13
Conifers 165

Continental blocks 17-ctinas
‘Continentality, 106-107, 126, 139, 162
Convergence 109

Gonvetin 105

Coombes, 65.

Cora:

Cyclonic at
press 1

1 112,157, 163

Dairy products, 166

Dame

Date palms, 136, 139

Day. FO: daylight, 5

Deciduous tree, so under Tres,
Forests

Deflation, 19, $-hollows 56, 58-59

Deforestation, 18

De

Sv arcane binds
Le ame «#4
Dekan
ai pli, ce under Plains
Denn TS a
posts pela 86 erigenous
Deponien.
Depostionl (atures), 48,43
NO
Depressions 11.136 (3, 150,156
Desens: 35: desert introns 185
Dow-point. 98
Diamonds 19
Different beating, 111
Diseases 120
Disease control, 133
Dsinbutarie 43
Diurnal etm), 111
Divergence 109
Dive (or watershed), 38
Doldrums 109
Done. 8

Epicentres 26
Epiphvti (plants), 118
Equator 6.7.8
Eduinones 6

Erg (desert), 59, 60
Erosion: 18,28) SÍ; marine 82

Glacial control theory. 82
Glacial dea 3
“Glacial

Glacial troughs 50
Glaciaion. 48,82
Glaciers 47: piedmont-48

Erostonal tires a8 Gare
ERS Sate
stares Gomes, 39, 40,44
Escapes 15.165 {Gout ae under Rocks: must
Evaporation, 108 171 Graduation 98
Repent eines Grapes ae
ln So at ong par 15. et spe
nore eal 13)

Fallowing, 127
Farms: ur 174; collective
ate, 152
ing arable, 166; pastoral,
ST 6 sales 17,

E
Ferrel lay of defection, 110
Festoons (snd ares) 9
Bima,

Firs LE

marie and ishing research 181;
Freshwater fishing 45, 70-71;
“grounds, 85

Fisures 26

Flash floods 60

Flax, 161

Flood plains see under Pains

og, 10,108 177,188 il 1S lad
10 radiation, 108; sea 108,

; a0 3
Fob Wn ener Winds
Rib romeo ts
Ras
Fort dk ool

comicos INLET

coc Hepa dis
Friction 8

Leseche, 143
Tevees. 43
Lianas 118
Light ius (or refracted), 6
Lignis, 13

on, 62-65, 80;-noas. 3
pavement, 6
Limon, 60
Limonite, 209
Lines of Weakness 15

Er.
an
Ein.
Feen

-
=
a
Se
Ei

TEvestck farming, 12; -cconomy,
Bs = E

Moine debris, 67
Mortlake, se under Lakes by
Mountains: residual, 17: of cesta
lation, 17; of denudation Iron
Hein D or on
16-17: id 14-15 volcan
Mats 7
fushroom rocks (or gour, sce un
Rocks og

Nappe 15

National pas, 131

Natural robber 113

Natural elo, se under

Vegetation

Nebula see under Galaxies

Negative movement, 44

Nolirungs 76

Neve 41038,

ee
made (mono
Notch, 73

ness), 133

ase or samp), 9,139
‘Oats. 166,178.

outwash, 18,33 tills 18, 52
Undulatng- 88. depositional 18
onal, 19: structural, 1,

udation, 19

the ecliptic, 5

12

Plankton, 85, 179

Plantations 119,12

Plateaux: 17-18, 134; itermont
à. 17: shallow

wwavepla
Playas 61
Plucking, 48,51
Plunge-pool 41
Pole 668
Polyps 80
Port
Positive movement, 44
Potatoes, 163,178
Prepon: 70,106 108,116
149-150, 164 171, 183-184,
uniformity of 177
Pressure 9596, 109: high
Til 12

11,113,
u

Revoles 4
Rin cous, 76
Res
Ridges
Ridge and furow landscape, 57
Rifles, see under Gaben

River capture, 39,40; <i 39 42
rejuvenation, #4; sourc dh,
system, 38

Roating Forties sec under Weser

Rock: basins SD: hour;
hummock, I; pedestal 57
salts 13.08: top Si

Rocks basic, 1: base 13
‘urbonaceous 13 ea, 12
Suse, 13: granite
3, 208; molen (ma
pluie, 13,20; sedimentary, 62
309 srta, 13; voeani 13

Roots Tong, 130, 136

Rotates à

Routeways, 53

Rubber se under Natural rubber

Runoft 38

Silk 13,20

Simons 139

Se ar

Slot 108,184

Siva slope 42

Slope 107

Smog. ser under Fog

Shout se under Méraines

Soon, 108, 14,171, RS montó
27 moine 47

Sodium corde 87

Sctwood. 2

SOI 0716 sere

Solr system, 1.2

So, ts

Sol (summer and wnt) 6117

Solution

Sounds,

Sou Bunter. 158

Souther temper 6

Spectrum, 108

Sper hae

Shine (or plo

Shin se

Spring, 143150

Machines 18 SS as nein, ance Bk, = ‘Spurs interlock
ites m en Tees
Mi ina glacier, 48. Oil, 139 ‚ramidal peak, see under Angular Salinity, 86, 88, 136. 74
alexa acid Sen lia on E nee Sen)
ee ais. A
Mantle (x mesophere), 12 ‘Oranges, 14d Quartzte, 13 sandstones, 13
res, 14 Quebracho, 158 Sand- blasting. see under Abrasion
a ae Eee
E 1 rfold, Radar sounding, 84 Savanna (or thorny scrubland), see Stratosphere,
one en Een ee oe
ee Sra een :
OA en a ae
Be. een la allen
Be Poa tia DE Ji E
i, Mel Pampas 18 on an, 78 blood (lon, 40 Sept com
Hr Pampero, 158 TP rime 150, santry, Seeds, 136, SS (ot wend

Parner sender Natal rl Suso
HET ST nées al ado are, 1, 134,164.16. D 2
Paral

Pass (plant 118
[Sid js peal oysters, 181

a 1,61

Summer 5 108, 11, 122,128, 49,
fsa Vath
au

(ormudstone) 13
a etes

her 138

for dome). 21
aoe Je) dr Vans
EURE
Shotts 6

sa

Trapping, 173 ais 56,60,
96-98, 106-107, Trailers 180 Water 105,137: depth of 0: head of
195 186, 183:annual_ Tes 150151 deeuous- 129,188, Ti-supply. À mare
DS Spas és cer II8:shori-, 129; “vapour 06: waters
123 126; mean mal, _ umbrelieshaped-. 129 desees 129; vaternay 3
1. Trenches 86 az Yale

E 122,14

Tipico Capos 67, 123,128,157 Waves 73

‘Hepa a mt 1 Wea 898-9410, 10;-cars

“Tropical (ones). 3 $4: forecast, 83

‘Troposphere, 105 there, 18.80.97

Trough ofa wave), 72 Whaleback" hummocks, 52

“Tsetse fies, 120,133, When, 136 151, 182.155 106

‘Tsunamis Winds Bere, 98-55,

‘Chinook 107,

110; Wester, 110, 142,150,
ee
eo.
le
mein

Wood pulp 74

‘Woollen textiles industry, 168

eres (rouge)

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