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![Page 1: geographiclongi l1](https://reader035.fdocuments.net/reader035/viewer/2022062522/577c7ddc1a28abe0549ffaa3/html5/thumbnails/1.jpg)
Daylight Saving in Temperate regions
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Longitudes
• Angular distance of a place from prime meridian
• Also called meridians• 0 degree = Greenwich in
UK• 180 degree =
International date line
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International Date Line
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• Earth rotates 360 °s in 24 hours
• 360/24 = 15°• 15° longitude • = 1 hour
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31st Dec MorningRussia
30th Dec Morning
Alaska
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International Date Line
Moving
West1 DAY Lost
Moving East1 DAY Gain
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1) Every country selects its standard meridian. 2) Angular distance between standard meridian of a nation to Greenwich meridian time (GMT)
Standard time
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• IST – 82.5 E Meridian• IST - 5.5 hours ahead
of GMT, so GMT+5.5
Indian Standard Time
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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
Chaibagaan time zone
IST
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Russian Time Zones
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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
Timezones
Question
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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
Timezones
Question
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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 amb) 10.38 amc) 10.22 amd) 9.22 am
Ans. B)
UPSC
Exercise
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Prelims 2006
Q. Through which one of the following groups of countries does equator pass?a) Brazil, Zambia and
Malaysiab) Columbia, Kenya and
Indonesiac) Brazil, Sudan and
Malaysiad) Venezuela, Ethiopia
and Indonesia
UPSC
Exercise
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Prelims 2008
Q. Which of the following cities is nearest to the equator ? a) Colombob) Jakartac) Manilad) Singapore
UPSC
Exercise
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Prelims
2008
Q. Which one of the following straits is nearest to the International Date Line? a) Malacca Straitb) Bering straitc) Strait of Floridad) Strait of Gibraltar
UPSC
Exercise
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Malacca strait
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Strait of Florida
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Strait of Gibraltar
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Prelims 2009
Q. Consider the following countries: 1. Australia2. Namibia3. Brazil4. ChileThrough which of the above does the Tropic of Capricorn pass?
UPSC
Exercise
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Prelims 2009
a) 1 onlyb) 2,3 and 4c) 1,2 and 3d) 1,2,3,4
UPSC
Exercise
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1. Longitude2. Latitude3. Reason for
Seasons on Earth
4. Time zones
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Self StudyNCERT Class6: Chapter 2- Longitudes, Latitudes and time-zones
Map: Greenwich line passes through which famous cities and countries of the world?
Map: IST line passes through which famous cities and states of India?
NCERT
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GEOMORPHOLOGY
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Origin of the EarthNebula TheoryTheory of Laplace
Overview
Geomorphology
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Gaseous cloud of H, He – radiation –cooling- Contracting • Separation of
outer ring – 9 parts => 9 planets
Origin of earth – Nebular theory of Laplace
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• Heavier elements near the core and lighter at the surface
• Layered structure of earth’s interior
Nebular Theory of Laplace
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1. Density study:2. Temperature study3. Structural study - Direct evidences- Indirect evidences
Interior of the Earth
Geomorphology
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• Outer layer (continents)– SIAL
• Mantle and oceanic crust – SIMA
• Core – Ni +Fe
Edward Suess
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• 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
Seismic wave studies
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S-wave Propagation
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P-waves propagation
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Observations• Asthenosphere –semi-
molten• Beyond
Asthenosphere- mantle rocks are dense • Outer core –liquid • The inner core is solid
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Self StudyClass11 Chapter3: Interior of Earth NCERT
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Earth as a whole• Iron (Fe) - highest• Oxygen (O2)• Silicon (Si)• Magnesium (Mg)• Sulphur (S)• Nickel (Ni)• Calcium (Ca)• Aluminum (Al) - lowest
• Oxygen (O2) - highest• Silicon (Si)• Aluminum (Al)• Iron (Fe)• Calcium (Ca)• Magnesium (Mg)• Sodium (Na)• Potassium (K) - lowest
Earth’s crust
Composition of the interior of the earth
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Igneous rocksMetamorphous rocksSedimentary rocks
Rocks in the
crust
Geomorpho
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Rock cycle
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formed due to solidification of magma (I) or lava (E)
They don’t have strata or layers
Because entire lava is solidified
They are crystallineThey don’t have fossils
IgneousRocks
Rock Types
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formed due to lithification of soil
erosion of rocks => deposition of granules => compaction => lithification
Always stratifiedThey may have fossils
Sedimentary rocks
Rock Types
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• both igneous and sedimentary rocks changed under heat or pressure or both
• No fossil• No stratification
Metamorphosed rocks
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gneissGranite
MarbleLimestone
quartziteSandstone
slate/ schistClay/mudsto
ne
Examples of metamorphosed rocks
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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
Prelims
2001
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Prelims 2001
Q. Quartzite is metamorphosed from:a) Limestoneb) Obsidianc) Sandstoned) shale
UPSC
Question
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Interior of the earth Different layers – structure and composition
Rocks Properties of rocks
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Geological time scale of Earthyears Eon Era Importa
nce4.6 -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
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Years Eon Era Period Epoch Importance
545 ml – 245 ml
Phanerozoic
Paleozoic Carboniferous
Coal
245 ml-65 ml
Mesozoic
Triassic, Jurassic, Cretaceous
Reptiles => Dinosaurs => extinct
65 ml – present
Cenozoic tertiary Oiligocene,Pliocene
Birds and mammals
65000 years
quaternary
Holocene
Human
Geological time scale of the Earth
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Rodinia in Pre-Cambrian
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Rodinia break up - Palaeozoic
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Mesozoic merger - Pangaea
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200 ml years ago – break up of Pangaea
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165 ml – break up of Gondwana
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Movement of India
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Continental drift Sea-floor spreading Plate tectonic theory
3 Theories
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Alfred Wegener
• 1st to propound movement of continents
• His Continental Drift Theory
• His 4 main observations
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1st ObservationMatching Coastlineszig-saw fit
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2nd ObservationSimilarity of Age of the rocks
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3th ObservationFossil evidences
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4th observationPalaeo-climatic evidencesGlacial evidenced in Tropical lands
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• Super continent - Pangaea• Ocean – Panthalasa• Continent – SIAL rocks• Ocean – SIMA rocks• Mid- Mesozoic Pangaea broke up and drifted
apart
Continental Drift Theory
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• Driving force?• Gravitational pull of sun and moon• Idea of SIAL and SIMA
Limitation of Continental Drift theory
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Limitation of Continental Drift theory
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Mains
2013
What do you understand by theory of continental drift? Discuss the prominent evidences in its support. (5)
UPSC
Question
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Prelims
2014
Q. Which of the following phenomena might have influenced the evolution of organisms?1. Continental drift2. Glacial cycles
Ans. Both
UPSC
Question
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Arthur Holmes
• Arthur Holmes:• Convection current
theory• Convection cells – force
behind drifting of continents
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Continental drift Sea-floor spreading Plate tectonic theory
3 Theories
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Sea-floor mapping• During 1940s and
1950s• Diversity of ocean-
floor• Submarine hills –
guoyts – MOR –Trench
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Questions:1) Ocean crust not older than mid-Mesozoic 2) Age increase away from MOR3) Sea-mounts deformed at trenches
Ocean floor mapping
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• 1960s Harry Hass and Dietz answered question regarding ocean mapping using convection theory
• revealed mystery of mid-oceanic ridge and trenches
Sea floor spreading Theory
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Mid- Oceanic Ridge
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Mid –Oceanic ridge
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• Rising limb of current breaks the Ocean crust• Basaltic eruption• Accumulation of lava – ridge => MOR• New Oceanic crust• Divergent limb – expansion of ocean crust
MOR
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Trenches
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• 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
MOR - Trench
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Mariana trench
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Prelims 2006
Q. In which one of the following oceans the Diamantina Trench is located?a) Pacific Oceanb) Atlantic Oceanc) Indian Oceand) Arctic Ocean
Ans. C)
UPSC
Question
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Diamantine trench
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Palaeo-magentism• Magnetism of rocks
along MOR • Magnetometer -
Magnetic parallel stripes– normal and reverse magnetic profile
• 1st Carlsberg ridge – Indian ocean
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• Vine and mattheus • Molten lava get polarity
geomagnetic field of that period -Solidify
• Ocean floor – magnetic tape
Palaeo-magentism
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conclusion1) Periodic reversal of magnetic field of the earth2) 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
Palaeo-magnetism
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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
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Continental drift Sea-floor spreading Plate tectonic theory
3 Theories