Lithosphere I - Tamil Nadu State Board

This lesson is to be studied for writing Stage 1 NTSE

1. NTSE (2021)
Lithosphere –I
Endogenic Processes

6. Lithosphere and
Crust notthe same
but also with upper
most part of the
mantle

7. All territorial planets
have Lithosphere

8. The lithospheres of
Mercury,
Venus, and Mars are
much thicker and
rigid

9. Crust
Outermost layer
“Skin of the earth”
5 to 30 kms
More thickness in
continental than oceanic
Two layers –SIAL and
SIMA

11. Mantle
Interior part
2900 kms thickness
Upper part solid
Lower part molten
Molten form ‘magma’

12. Core
Innermost
Hottest
NIFE (Nickel and Ferrus)
Solid Inner core & Liquid outer core
Gravitation –due to solid iron
Liquid outer core spins over inner
core hence generates magnetic field

13. Rocks –aggregate of
minerals
Petrology–Study of rocks
Hard like granite
Soft like clay
Loose like sand

14. The deepest
artificial hole dug -
In 2012, Z-44
ChavyoWell
(Western Russia)
(12,376m)

15. Igneous Rocks
‘igneous’ -Latin word Ignis
-‘Fire’.
‘Magma’. ‘Lava’.
The lava cools & solidified
Granite and basalt
Primary or Mother rocks

16. Sedimentary Rocks
Latin 'sediment' meaning settle.
Rivers, glaciers and winds
transport and deposit them in
layers.
After a few million years, these
deposits form as Sedimentary
rocks.

17. Sedimentary Rocks
The bodies of plants and animals that
fall on the deposits get embedded
in the layers and form Fossils.
Sandstone, limestone, chalk,
gypsum, coal and conglomerate are
examples of sedimentary rocks.

18. Metamorphic Rocks
The word ‘metamorphosis’, which
means, ‘change of form’. Parent rocks
under extreme heat and pressure 
change.
Granite to gneiss
Basalt Schist
Limestone Marble
Sandstone Quartzite.

19. Rock Cycle
Transformation
of one rock to
another

20. Geomorphic Processes
Endogenic –Forces acting from
earth’s interior, shape the
topographic relief

21. Exogenic Processes
The forces that act on the
surface of the Earth due to
natural agents like running
water, glacier, wind, waves
etc. are called exogenic
processes.

22. Internal processes
generate heat and
eject materials from
deep below the earth’s
crust with the power
of internal
radioactivity.

23. Plate Tectonics
Major rock mass
Major plates and minor plates
Plates float over the mantle
Collisions Irregular surface
features
Plates movement due to
thermal energy

24. Types of Plate Boundary
Convergent boundary
When plates collides against
each other
Divergent boundary
When each plate move away
from each other
Transform boundary
When plates slides against
each other

25. Movement of Continental
Plates
Plates move upwards and
downwards due to lateral
compression which is called
foldingresults in the
formation of fold mountains

26. The plates keep moving
The continents too move
Ex:250 million years ago Indian
Plate was a part of Gondwana
Land but 140 million years ago it
got broken with Gondwana land
and started colliding with Asiaas
a result the formation of
Himalayasand Tibetian Plateau

27. Earthquake
Sudden vibrations in the
Earth’s crust
Point of origin –Focus or
Hypocentre
Epicentre is the point at
which on the surface it is
felt

29. Seismic wavesgenerated by
earthquake
Nature, force and speed varies
according to the medium
through which it passes

30. Seismic –Primary or P-
waves
Fastest of all seismic waves
It can travel through liquid,
solid and gases
Velocity5.6km to 10.6km
per second

31. Secondary or S-waves solids.
These transverse waves shake the
ground perpendicular to the
direction in which they propagate.
Velocity of these waves is 1 km
per second to 8 km per second.

32. Surface Waves (or) L-waves
are similar to P-waves 
along the ground surface.
Slower and are the most
destructive waves
Velocity -1 km per second
to 5 km per second.

33. C.F. Richter devised a scale to
measure the magnitude of
Earthquakes.
The highest magnitude ever
recorded is 9.5 on Richter
scale
(Bio-Bio, Chile in 1960).

34. The study of the
earthquakes 
Seismology

35. Tsunami–Japanese term ‘
harbour waves
generated by earthquake
travel with speed 500km/ hour
length of the waves 600 mts
height 15 metres
2004 tsunami –2.8 lakhs dead,
600 kms / hour, triggered near
Indonesia took 7 hours to reach
Chennai

36. Tsunami -26/Dec/2004
Due to subduction of Indo-
Australian plate over
Eurasian plate
Magnitude 9 –Richter Scale
Earthquake triggered seafloor
to uplift thereby displacing
water to move

37. Volcano
Magma comes out through
a vent or opening on the
surface erupt out

38. Volcano
Formed when plates
move apart
Major component –Magma
chamber (large pool of liquid),
vent (opening) and volcanic
cone (land form) Crater –
depression on the top of the
volcano

39. Volcano Classification –
Periodicity
Active –constantly eject
Dormant –Sudden
eruption but no sign like
Fuji
Extinct –permanently
stopped erupting like
Kilimanjaro

40. Volcano –Structure and
Composition
Composite –Conical in a
layered form, hardened lava
Volcanic Dome –Circular
mound formed due to slow
eruption
Shield –Intense viscous lava

41. Earthquake & Volcano –
Distribution
Along the plate boundary
–Circum Pacific Ring of
Fire

42. Constructive Effects of
Volcanoes
Enrich soil fertility
Promotes agriculture
Generates geothermal
energy
Attractive tourist spots
Used as building materials too

43. Destructive Effects of
Volcanoes
Flash flood
Mud slide
Rock fall
Alter weather conditions
Dust causes breathing
difficulties
Disrupt transportation