Daylight Saving in Temperate regions

Longitudes

• Angular distance of a place from prime meridian

• Also called meridians• 0 degree = Greenwich in

UK• 180 degree =

International date line

International Date Line

• Earth rotates 360 °s in 24 hours

• 360/24 = 15°• 15° longitude • = 1 hour

31st Dec MorningRussia

30th Dec Morning

Alaska

International Date Line

Moving

West1 DAY Lost

Moving East1 DAY Gain

1) Every country selects its standard meridian. 2) Angular distance between standard meridian of a nation to Greenwich meridian time (GMT)

Standard time

• IST – 82.5 E Meridian• IST - 5.5 hours ahead

of GMT, so GMT+5.5

Indian Standard Time

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

Russian Time Zones

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

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

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

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

Prelims 2008

Q. Which of the following cities is nearest to the equator ? a) Colombob) Jakartac) Manilad) Singapore

UPSC

Exercise

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

Malacca strait

Strait of Florida

Strait of Gibraltar

Prelims 2009

Q. Consider the following countries: 1. Australia2. Namibia3. Brazil4. ChileThrough which of the above does the Tropic of Capricorn pass?

UPSC

Exercise

Prelims 2009

a) 1 onlyb) 2,3 and 4c) 1,2 and 3d) 1,2,3,4

UPSC

Exercise

1. Longitude2. Latitude3. Reason for

Seasons on Earth

4. Time zones

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

GEOMORPHOLOGY

Origin of the EarthNebula TheoryTheory of Laplace

Overview

Geomorphology

Gaseous cloud of H, He – radiation –cooling- Contracting • Separation of

outer ring – 9 parts => 9 planets

Origin of earth – Nebular theory of Laplace

• Heavier elements near the core and lighter at the surface

• Layered structure of earth’s interior

Nebular Theory of Laplace

1. Density study:2. Temperature study3. Structural study - Direct evidences- Indirect evidences

Interior of the Earth

Geomorphology

• Outer layer (continents)– SIAL

• Mantle and oceanic crust – SIMA

• Core – Ni +Fe

Edward Suess

• 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

S-wave Propagation

P-waves propagation

Observations• Asthenosphere –semi-

molten• Beyond

Asthenosphere- mantle rocks are dense • Outer core –liquid • The inner core is solid

Self StudyClass11 Chapter3: Interior of Earth NCERT

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

Igneous rocksMetamorphous rocksSedimentary rocks

Rocks in the

crust

Geomorpho

Rock cycle

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

formed due to lithification of soil

erosion of rocks => deposition of granules => compaction => lithification

Always stratifiedThey may have fossils

Sedimentary rocks

Rock Types

• both igneous and sedimentary rocks changed under heat or pressure or both

• No fossil• No stratification

Metamorphosed rocks

gneissGranite

MarbleLimestone

quartziteSandstone

slate/ schistClay/mudsto

ne

Examples of metamorphosed rocks

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

Prelims 2001

Q. Quartzite is metamorphosed from:a) Limestoneb) Obsidianc) Sandstoned) shale

UPSC

Question

Interior of the earth Different layers – structure and composition

Rocks Properties of rocks

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

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

Rodinia in Pre-Cambrian

Rodinia break up - Palaeozoic

Mesozoic merger - Pangaea

200 ml years ago – break up of Pangaea

165 ml – break up of Gondwana

Movement of India

Continental drift Sea-floor spreading Plate tectonic theory

3 Theories

Alfred Wegener

• 1st to propound movement of continents

• His Continental Drift Theory

• His 4 main observations

1st ObservationMatching Coastlineszig-saw fit

2nd ObservationSimilarity of Age of the rocks

3th ObservationFossil evidences

4th observationPalaeo-climatic evidencesGlacial evidenced in Tropical lands

• Super continent - Pangaea• Ocean – Panthalasa• Continent – SIAL rocks• Ocean – SIMA rocks• Mid- Mesozoic Pangaea broke up and drifted

apart

Continental Drift Theory

• Driving force?• Gravitational pull of sun and moon• Idea of SIAL and SIMA

Limitation of Continental Drift theory

Limitation of Continental Drift theory

Mains

2013

What do you understand by theory of continental drift? Discuss the prominent evidences in its support. (5)

UPSC

Question

Prelims

2014

Q. Which of the following phenomena might have influenced the evolution of organisms?1. Continental drift2. Glacial cycles

Ans. Both

UPSC

Question

Arthur Holmes

• Arthur Holmes:• Convection current

theory• Convection cells – force

behind drifting of continents

Continental drift Sea-floor spreading Plate tectonic theory

3 Theories

Sea-floor mapping• During 1940s and

1950s• Diversity of ocean-

floor• Submarine hills –

guoyts – MOR –Trench

Questions:1) Ocean crust not older than mid-Mesozoic 2) Age increase away from MOR3) Sea-mounts deformed at trenches

Ocean floor mapping

• 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

Mid- Oceanic Ridge

Mid –Oceanic ridge

• 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

Trenches

• 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

Mariana trench

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

Diamantine trench

Palaeo-magentism• Magnetism of rocks

along MOR • Magnetometer -

Magnetic parallel stripes– normal and reverse magnetic profile

• 1st Carlsberg ridge – Indian ocean

• Vine and mattheus • Molten lava get polarity

geomagnetic field of that period -Solidify

• Ocean floor – magnetic tape

Palaeo-magentism

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

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

Continental drift Sea-floor spreading Plate tectonic theory

3 Theories