The lithosphere consists of the crust and uppermost mantle. It is thicker on Mercury, Venus, and Mars than Earth. The crust is the outermost layer and varies in thickness between continents and oceans. Below the crust is the mantle, which is solid on top and molten below. The innermost core is hot and composed of iron and nickel. Rocks are composed of minerals and classified as igneous, sedimentary, or metamorphic based on their formation. The movement and collision of tectonic plates shapes the Earth's surface features and causes earthquakes and volcanic activity along plate boundaries.
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.
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
folding results 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 Asia as
a result the formation of
Himalayas and 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
30. Seismic – Primary or P-
waves
Fastest of all seismic waves
It can travel through liquid,
solid and gases
Velocity5.6km 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).
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
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
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