Geomorphic processes

Geomorphic processes

1. SEMINAR
ON
GEOMORPHI
C PROCESSES

2. CONTENT
GEOMORPHIC PROCESS
INTRODUCTION
EXOGENETIC PROCESS
ENDOGENETIC PROCESS
EXTRA-TERRESTRIAL PROCESS
CONCLUSION
REFERENCE

3. INTRODUCTION
The geomorphic process are all those physical and
chemical changes which effect a modification of the
earth surficial form.
A geomorphic agent is any natural medium, which is
capable of securing and transporting earth material.
The leading natural agencies that play a major role in
this cycle of making and breaking are :-
Running water, ground water, waves and currents,
wind, glaciers, lakes and swamps, volcano's and
earthquake and living organism.
Most of the geomorphological agents are originate
with in the earths atmosphere and are directed by the
force of gravity and energized by the sun.

5. DEGRADATION
The process of reducing the elevation of a high
land due to the removal of material by the
geomorphic agent may be described as
degradation.
Degradation of earth surface is chiefly brought by

Weathering
Mass wasting
Erosion

6. WEATHERING

7. PHYSICAL WEATHERING

8. FROST ACTION

9. FROST WEDGING
It is a common process of physical weathering in
sub polar region where temperature often vary
around freezing point of water
Rock break down caused by expansion of ice in
cracks or joint

10. CRYSTAL GROWTH
Growth of crystal in rock fracture with the
evaporation of saline ground water causes
disintegration
The salt is in solution and precipitate as soil
water and ground water evaporate.
It is most effective in dry land landscapes where
water tables are near the surface (e.g., saline
seeps)

11. THERMAL EXPANTION &
CONTRATION
Repeated daily heating cooling of causes
expansion & contraction
Different minerals expand & contract at different
rates causing stress along mineral boundaries
Thermal expansion due to the extreme range of
temperatures shutter rocks in desert
environments
Repeated swelling and shirking of minerals with
different expansion rates will also shatter rock

12. EXFOLIATION
Rock breaks off into leaves or sheets along joints
which parallel the ground surface.
Expansion makes cracks parallel to surface.
Contraction makes crack right angle to surface.
Layers of rock peel off as expansion alternates
with contraction

13. CHEMICAL WEATHERING
Chemical weathering is the process by which
rocks are decomposed or dissolved or loosened by
chemical processes to form residual material.
The agents of chemical weathering are;
Water,Oxygen,CO2,Living organism, Acid rain.

14. HYDRATION
The process where minerals in the rock absorb
water and expand, creating stress which cause
the disintegration of rock.
Eg:CasO4+2H2O CasO42H2O

15. HYDROLYSIS
Hydrolysis is a chemical weathering process
affecting silicate minerals.
In such reactions, pure water ionizes slightly and
reacts with silicate minerals.

16. SOLUTION
It is the process by which rock is dissolved in
water.
It is strongly influenced by pH and temperature.
When water becomes saturated, chemicals may
precipitate out forming evaporate deposits.
Calcium carbonate(calcite, limestone),sodium
chloride(salt), and calcium sulphate(gypsum) are
particularly vulnerable to solution weathering.

17. OXIDATION
Iron combines with oxygen in the presence of water
to form iron hydroxide. This processes called
oxidation

18. CARBONATION
It is the action of CO2 in combination with the
water which give rise to carbonic acid which is
tern responsible for dissolving various rock &
minerals
E.g. calcium carbonate + water + carbon dioxide
calcium carbonate

19. MASS - WASTING
Mass wasting is the process that involves the
spontaneous downward movement of soil,
regolith and rock under influence of gravity
Mass wasting is usually aided by the presence of
water but without any dynamic action of it or in
other words the amount of water present is not
sufficient to act as a transporting medium
The process occur at speeds ranging from those
which are so slow that the movement is
imperceptible to rapid flow and catastrophic
slumping and rock falls
Evidences of the down slope movement of rock
and soil is found almost universally

20. EROSION
Erosion is the process associated with the
geomorphological agents like :-wind, river,
glaciers etc.
By which rock materials are loosen or dissolved
and then transported from one place to other
Erosion consist of process like :-
Collecting together of the loose material produced
by weathering
Wearing down the surface and curve out valley
features which is commonly known as abrasion &
corrosion

21. AGGRADATION
The process of living up of low land due to the
addition or deposition of material by the agents
of gradation
During the transportation an agent like wind,
water, glacier, ocean, waves

22. VOLCANISM
Volcanism includes the movement of rock or
magma towards the earth surface
It beyond the scope of geomorphology to explain
the complex changes with in the earth which
indicate volcanism
Molten rock may be extruded through centralized
vents called volcanoes

23. DIASTROPHISM
Diastrophic process are usually classified into
two types
Organic (mountain-building with deformation)
Epirogenic (regional uplift without important
deformation)
Organic movements are more localized than are
epirogenic and usually involve tangential forces
with resulting compression or tension of rock
strata

24. IMPACT OF METEORITES
Probably the most usually land forms are those
that originate from the impact of meteorites
 Such forms are rather rare but approximately
fifty well
Substantiated meteorite craters are known to
exist
Their uniqueness lies in the fact that they were
produced by extra-terrestrial agents, although
the earths gravitate alteration was responsible
for the in fall of the meteorites

25. CONCLUTION
The geomorphological process, as already
indicated, play significant roles in shaping the
surface of the earth
Depending up on their individual nature and
mode of operation, the processes classified into
two categories
Exogenetic process
Endogenetic process
Impact of meteorites is considered as a special
category is named as extraterrestrial

26. REFERENCE
WILLIAM D. THORNBURY, (1954),
PRINCIPLES OF GEOMORPHOLOGY, Page
No:-34
Dr.A.V.GEORGE, M.N.RAJESH, T.S.SABITHA
(2005),AN INTRODECTION TO PHYSICAL
GEOLOGY AND GEOMORPHOLOGY
BERNAND W.PIPKIN AND D.D.TRENT,(2001),
GEOLOGY AND THE ENVIORMENT
PARBIN SINGH, ENGINEERING AND
GENARAL GEOLOGY
RAUL A DEJU AND Et al,(1972),THE
ENVIORMENT AND ITS RESOURCES

27. CONT……..
S.M.MATHUR,(2008),ELEMENT OF GEOLOGY
G.B.MAHAPATRA,(1994),TEXT BOOK OF
PHYSICAL GEOLOGY
P.K.MUKERJEE,(1962),A TEXT BOOK OF
GEOLOGY