This document provides an overview of plate tectonic theory, which unified and improved upon earlier continental drift and sea-floor spreading theories. It discusses key evidence for plate tectonics from ocean floor mapping and paleomagnetism studies. Mapping revealed the global mid-ocean ridge system and age dating showed sea floors are younger further from ridges, supporting the idea of sea floor spreading. Paleomagnetism data also indicated periodic reversals of the Earth's magnetic field and allowed calculation of spreading rates.
2. Study material
ATLAS
• Orient Longman
• Study publication – India
and world
• Oxford publication
Book list
• Goh Cheng Leong
• Physical Geography – by
Savinder singh
• India: comprehensive
geography by D.R. Khullar
4. Meaning and span of Geography
• Geo= earth and Graphy = study,
which means study of earth
• Geography can be divided into two
parts:
• Physical geography and Human
geography
5. Two Parts of Geography
Physical
• Landforms
• Atmosphere
• Hydrosphere
• Biosphere
Human
• Habitation
• Population
• Agriculture
• Industries-
resources
8. Latitudes
• Largest latitude –
equator
• Tropics – heat
surplus
• Temperate, polar
regions – heat
deficit
• Responsible for
pressure system
and planetary
wind system
10. Q. Who among the following was
first to state that Earth was
spherical?
A. Aristotle
B.Copernicus
C.Ptolemy
D.Strabo
UPSC Prelims 2001
Correct Answer is A
13. Prelims
2013
Q. Variations in length of
daytime and night-time from
season to season are due to
a) Earth’s rotation on its
axis
b) Earth’s revolution
around the sun in an
elliptical manner
c) Latitudinal position of
the place
d) Revolution of earth on a
tilted axis
UPSC
Question
14. Prelims
2013
Variations in length of
daytime and night-time from
season to season are due to
a) Earth’s rotation on its
axis
b) Earth’s revolution
around the sun in an
elliptical manner
c) Latitudinal position of
the place
d) Revolution of earth on a
tilted axis
UPSC
Question
16. Longitudes
• Angular distance of
a place from prime
meridian
• Also called
meridians
• 0 degree =
Greenwich in UK
• 180 degree =
International date
line
21. Standard time
1) Every country selects its standard
meridian.
2) Angular distance between standard
meridian of a nation to Greenwich
meridian time (GMT)
23. British launched
Chaibagaan time (1 hr
ahead of IST) 150 years
ago in Assam
After independence –
rejected
2007 DST study –
rejected – admin
challenges
Jan 2014 CM of Assam –
declare to apply
Chaibagaan time
Chaibagaa
n time zone
IST
25. If 12 noon at GMT what
is the time at 75 °E?
• Difference = 75 °
• 15 ° => 1 hour
• 75 ° => 5 hours
• East (means add) 12
+5 = 5 pm
Time
zones
Question
26. If 12 noon at GMT what
is the time at 30 °W?
• Difference = 30 °
• 15 ° => 1 hour
• 30 ° => 2 hours
• East (means minus)
12 - 2 = 10 am
Time
zones
Question
27. Prelims
1999
Q. If it is 10.00 am IST,
then what would be the
local time at Shillong on
92 deg E Longitude?
a) 9.38 am
b) 10.38 am
c) 10.22 am
d) 9.22 am
Ans. B)
UPSC
Exercise
28. Prelim
s
2006
Q. Through which one of the
following groups of countries
does equator pass?
a) Brazil, Zambia and
Malaysia
b) Columbia, Kenya and
Indonesia
c) Brazil, Sudan and
Malaysia
d) Venezuela, Ethiopia and
Indonesia
UPSC
Exercise
29. Prelims
2008
Q. Which of the
following cities is
nearest to the equator ?
a) Colombo
b) Jakarta
c) Manila
d) Singapore
UPSC
Exercise
30. Prelims
2008
Q. Which one of the
following straits is
nearest to the
International Date Line?
a) Malacca Strait
b) Bering strait
c) Strait of Florida
d) Strait of Gibraltar
UPSC
Exercise
34. Prelims
2009
Q. Consider the
following countries:
1. Australia
2. Namibia
3. Brazil
4. Chile
Through which of the
above does the Tropic of
Capricorn pass?
UPSC
Exercise
38. Origin of the Earth
Nebula Theory
Theory of Laplace
Overview
Geomorpholo
gy
39. Origin of earth – Nebular theory of
Laplace
Gaseous cloud
of H, He –
radiation –
cooling-
Contracting
• Separation of
outer ring – 9
parts => 9
planets
40. Nebular Theory of Laplace
• Heavier
elements near
the core and
lighter at the
surface
• Layered
structure of
earth’s
interior
41. 1. Density study:
2. Temperature study
3. Structural study
- Direct evidences
- Indirect evidences
Interior of
the Earth
Geomorpholog
y
42. Edward Suess
• Outer layer
(continents)– SIAL
• Mantle and oceanic
crust – SIMA
• Core – Ni +Fe
43. Seismic wave studies
• Seismic waves = mechanical waves =
require medium for propagation
• Their behaviour changes with changes of
medium
• 2 imp waves: primary P and secondary S
waves
• S waves can travel into only S and G
medium
• P can travel in all 3 mediums
• But speed is highest in S>L>G
50. formed due to
solidification of magma
(Interior) or lava
(Exterior)
They don’t have strata or
layers
Because entire lava is
solidified
They are crystalline
They don’t have fossils
Igneous
Rocks
Rock
Types
51. formed due to
lithification of soil
erosion of rocks =>
deposition of granules
=> compaction =>
lithification
Always stratified
They may have fossils
Sedimentary
rocks
Rock Types
52. Metamorphosed rocks
• both igneous and sedimentary rocks
changed under heat or pressure or
both
• No fossils
• No stratification
53. Examples of metamorphosed rocks
gneiss
Granite
Marble
Limestone
quartzite
Sandstone
Slate/ schist
Clay/muds
tone
54. Prelims
2001
Consider the following
statements made about
sedimentary rocks:
1. Sedimentary rocks are
formed at earth’s surface by
hydrological system
2. Formation of sedimentary
rocks involves the
weathering of pre-existing
rocks
3. Sedimentary rocks contains
fossils
4. Sedimentary rocks occur in
layers
UPSC
Question
56. Interior of the earth
Different layers – structure and
composition
Rocks
Properties of rocks
57. Geological time scale of Earth
years Eon Era Importanc
e
4.6 -3.5
billion
Pre-
Cambrian
Proterozoic No Life
3.5 -2.5
billion
Archean 1st life form
2.5 to 545
million
Hadean 1st fish
eveloved
58. Geological time scale of the Earth
Years Eon Era Period Epoch Importan
ce
545 ml –
245 ml
Phaneroz
oic
Paleozoic Carbonife
rous
Coal
245 ml-65
ml
Mesozoic Triassic,
Jurassic,
Cretaceou
s
Reptiles
=>
Dinosaur
s =>
extinct
65 ml –
present
Cenozoic tertiary Oiligocene
,
Pliocene
Birds and
mammals
65000
years
quaternar
y
Holocene Human
74. Main
s
2013
What do you understand
by theory of continental
drift? Discuss the
prominent evidences in its
support. (5)
UPSC
Question
75. Preli
ms
2014
Q. Which of the following
phenomena might have
influenced the evolution
of organisms?
1. Continental drift
2. Glacial cycles
Ans. Both
UPSC
Question
76. Arthur Holmes
• Arthur Holmes:
• Convection current
theory
• Convection cells – force
behind drifting of
continents
78. Sea-floor mapping
• During 1940s
and 1950s
• Diversity of
ocean-floor
• Submarine hills
– guoyts – MOR
–Trench
79. Ocean floor mapping
Questions:
1) Ocean crust
not older than
mid-Mesozoic
2) Age increase
away from MOR
3) Sea-mounts
deformed at
trenches
80. Sea floor spreading Theory
• 1960s Harry Hass and Dietz answered
question regarding ocean mapping using
convection theory
• revealed mystery of mid-oceanic ridge and
trenches
83. MOR
• Rising limb of current breaks the Ocean crust
• Basaltic eruption
• Accumulation of lava – ridge => MOR
• New Oceanic crust
• Divergent limb – expansion of ocean crust
85. MOR - Trench
• At trench Ocean floor
destroyed – melted in
mantle
• Oceanic crust heavier
than continental crust
• Ocean floor act like
conveyor belt
• Ocean floor – cyclic
process – 300 ml yrs
87. Prelims
2006
Q. In which one of the
following oceans the
Diamantina Trench is
located?
a) Pacific Ocean
b) Atlantic Ocean
c) Indian Ocean
d) Arctic Ocean
Ans. C)
UPSC
Question
89. Palaeo-magentism
• Magnetism of rocks
along MOR
• Magnetometer -
Magnetic parallel
stripes– normal and
reverse magnetic
profile
• 1st Carlsberg ridge –
Indian ocean
90. Palaeo-magentism
• Vine and mattheus
• Molten lava get polarity
geomagnetic field of
that period -Solidify
• Ocean floor – magnetic
tape
91. Palaeo-magnetism
conclusion
1) Periodic reversal of magnetic field of the
earth
2) Rate of sea-floor spreading decided by age +
distance between two equal magnetic stripes
• Atlantic – 1.0 cm/ year
• Indian – 1.5 cm/year
• Pacific – 6.0 cm/year
92. Prelims
2011
Q. Between India and East
Asia, the navigation time
and distance can be greatly
reduced by which of the
following?
a) Deepening Malacca strait
between Indonesia and
Malaysia
b) Opening a new canal
across Kra Isthmus
between gulf of Siam and
Andaman sea
UPSC
Question
World Geography:
Asia= China, Japan, South East Asia, West Asia
Europe = UK, Russia, Germany-France, Eastern Europe
North America = USA, Canada
South America and Africa