Physiograpy of In"a Introduction Physiography of India

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Revision A note about the symbol " ⇒ " : Just ensure that you revise This symbol means " implies / leads this module directly whenever to / causes " and has been used you need to revise this topic . extensively in our notes . ¥If you have any doubts/queries , mail us on [email protected] . If you cant understand For example , in Himalayan and ¥We will send you more such free material periodically with even better learning aids something , you may easily Peninsular mountains , their young , we are working on . All our modules will be complete in themselves and will go a long refer to that particular section weak and flexible geological way in easing some of the burden of the syllabus on you . in the books . structure leads to an interplay between exogenetic and The mindmapping technique endogenetic forces . We express ensures that you use both left this in the notes as : and right hemispheres of your young , weak and flexible geological brain while learning and structure ⇒ interplay between ensure a much better retention and reproduction in the exam . exogenetic and endogenetic forces . Geo VI - Ch. 7 - page 2 Physical divisions of India

Northern Indian Plains fertile land for cultivation ⇒ High concentration of population

Northernmost : Great Himalaya / Himadri

Himalayas : 3 main parallel ranges South of the above : Middle Himalaya/Himachal

Southernmost : Shivalik

Tsunami : Alluvial deposits : Tributary : Peninsular plateau : rich in minerals like coal and iron ore a huge sea wave generated due to very fine soils brought by rivers and river/stream discharging its waters an earthquake on the floor deposited in the river basins to a main river from either side

Important terms

Delta: area of land formed at the mouth of the river Mouth of river : where rivers enter the sea

Corals

skeletons of tiny marine animals : polyps

when polyps die - skeletons left

other polyps grow on the skeleton

this grows higher and higher , forming the coral islands Geo IX - Ch. 2 - page 2 Geologically : Young Structurally : fold mountains folds : asymmetrical composition : highly compressed and altered rocks

great himalayas composition : granite imp range : mahabharat

No. of glaciers snow bound : perennially The Himalayan Mountains Himachal / lesser himalaya Kashmir

imp valleys Kangra Composition : unconsolidated sediments brought down by rivers. Shiwalik Kullu divisions from W to E divided by river valleys Altitudinal variations

covered with thick gravel and more in eastern half then in western half alluvium

Indus Satluj Kali Tista Dihang Brahmaputra marks the eastern most boundary Punjab Himalaya ( / Kashmir / Kumaon Himalayas Nepal Himalayas Assam Himalayas Himachal Himalaya )

Himalayas bend sharply here and extend to eastern composition : strong sandstones ( sedimentary ) boundary - Purvanchal

Northern Plain split into numerous deposition of silts channels→distributaries soil cover : rich

rivers’ in lower course agriculturally very productive water supply : adequate

climate : favourable three sections

⇒ forms riverine islands due to gentle slope , velocity of river ⬇

Majuli on Brahmaputra west - punjab plains Ganga plain - b/w Brahmaputra plain ( largely in Pak ) Ghaggar and Teesta - Assam

The soil in the bhangar region contain - calcerous deposits called kankar Geo IX - Ch. 2 - page 3 volcanic origin ⇒igneous rocks denuded over time ⇒ leading to formation of black soil Composition : old crystalline , igneous and metamorphic rocks Deccan trap Black soil

formed - due to breaking and drifting of the Peninsular Plateau gondwana old - part of the oldest landmass

highly eroded ⇒ found as broken hills Aravali hills

Northern extension - Meghalaya , Deccan Plateau Central Highlands Karbi anglong plateau , NORTH river flow : SW to NE ⇒ slope towards east CACHAR HILLS

wider in west , narrower in east by facing the rain bearing moist winds to rise along the western slopes cause orographic rain W.Ghats Bundelkhand eastward extension

Baghelkhand

Chotanagpur drained by Damodar plateau

Corals short lived microscopic organisms

live in colonies

coral polyps fringing reef need shallow , mud free , warm water Importance of various Physiographic units Mountains : source of water and forest wealth secrete calcium carbonate this alongwith their skeletons form reefs barrier reef eg. great barrier reef of Aus Northern plains : Granaries

Plateau : mineral wealth

Coast and islands : fishing and ports

atoll - circular / horse shoe shaped Geo XI (2) - Ch. 2 - page 1

460 mn yrs old Still Continues… N endogenetic India

changed by forces … Earth Indo Aus Plate initially : South of Equator broke apart Aus

exogenetic Eg. rift valleys of narmada , tapi , SE movement mahanadi and block mountains of satpura ( see fig . on left )

vertical movements block faulting

Overlaying the block : desert and desert like features subjected to

3 Geological Divisions of India

Rajasthan As part of Indo Aus plate

Also its parts are … Karbi Anglong gneisses

Meghalaya Plateau The peninsular Block formation by ancient…

granites part of w. coast submerged under sea

Northern boundary

rigid since cambrian period exceptions

river some parts changed shallow by tectonic activity NE parts separated by Malda fault ( WB) from Chhotanagpur Plateau valleys low gradients

consist of relic and residual mountains ( see map on next page ) east flowing ones - form deltas ( see map on next page ) Geo XI (2) - Ch. 2 - page 2 gorge 3 geological divisions of India ( contd…) origin : tectonic ⇒ dissected by fast flowing Max development during 3rd phase youthful rivers⇒ ⇒ V shaped valleys of himalayan mountain formation ⇒ The himalayas and other peninsular rapids and waterfalls originally : geosynclinal mountains depression

Indo-Ganga- gradually , filled by Brahmaputra Plain sediments from himalayan and peninsular rivers faults young , weak and flexible exogenetic F ⇒ geological structure ⇒ ⇒ interplay of ⇒ folds avg depth of alluvial deposits : endogenetic F 1000-2000 m ⇒ thrust plains

affects other aspects

⇒

Geological str of India significant variations

of an area is the outcome of … Physiography relief

structure process stage of development

physiographic divisions of india

Mahendragiri is the highest peak on the eastern ghats Geo XI (2) - Ch. 2 - page 3 trans himalayas

length : 2500 km ( E to W ) great himalayas ( / great himalayan range Inner Himalayas / ( central axial range ) Himadri )

width : 160-400 km ( N to S ) middle himalayas shivalik North and NE mountains Himalayas series of parallel mountain ranges

climatic

act as a divide between Indian A number of valleys subdivisions of Himalayas ( see drainage lie in between map ) on basis of … subcontinent and C. and E. Asia cultural

physical relief alignment of ranges other geomorphological features

Siachen Baltoro Indus and its tributaries cultivation of a kind of saffron : zafran Series of ranges imp. glaciers drained by formation of Karewa : thick deposits of glacial clay and other materials embedded with moraines

Kashmir / NW himalayas Vaishno devi pilgrimage Amarnath cave

Charar e sharif Imp. passes Lakes South : longitudinal valleys ( duns ) Jhelum Srinagar

caused by : local base level youth stage but forms meanders provided by erstwhile larger lake freshwater salt Jammu dun Pathankot dun ( which is a mature stage ch/ in the ( of which the prsent Dal lake is a evolution of fluvial landform ) small part )

Dal Wular Tso Moriri Pangong Tso Geo XI (2) - Ch. 2 - page 4 Satluj slope - moderate Beas Chandrika Kalka dun Yamuna Ghaghra Britishers introduced tea soil - thick , high organic content plantations because of climate : well distributed Ravi rain and mild winters nalagarh dun Indus system Ganga system Dehra dun largest Kanchenjunga river - Tista ( kanchengiri ) dun formations

drained by Harike dun West : Nepal Darjiling and Sikkim Himalayas East : Bhutan

Himachal and Uttarakhand Himalayas distinguishing features Kota dun higher regions : Lepcha Northern most part

absence of shivaliks tribes all 3 ranges present extension of Ladakh cold desert - Spiti lower : nepali , bengali and from origin of word shivalik : central india geological found in and around duar formations more important a place called Sivawala ( also used for tea gardens ) Great himalayan range Lesser himalayas Shivalik UK : Nagtibha

valleys inhabited by … locally known as Kameng perennial and high rate of fall HP : Dhauladhar Brahmputra - flows through a deep Subansiri gorge after crossing namcha barwa ⇒ Imp rivers Dihang Bhotias : nomadic grps - migrate to high Dibang highest hydroelectric potential summer grasslands ( bugyals ) during dissected by fast flowing N to S summer and return in winter to valleys rivers ⇒ deep gorges Lohit

East of Bhutan Arunachal Himalayas Diphu pass Valley of flowers rugged topography Tribals Places of importance in HP and UK Himalayas ⇒

Gangotri W to E : Monpa , Daffla , Abor , Mishmi , Nishi , Nagas nominal inter valley transportation linkages Yamunotri Five prayags ⇒ most practice shifting cultivation Imp Mt Kedarnath so , most of the interactions are carried through the duar region along the arunachal assam border Badrinath Kangtu Namcha Barwa Hemkund Sahib Geo XI (2) - Ch. 2 - page 5 tributary of Irrawady in Myanmar

form tributaries of Brahmaputra rivers in E. Manipur tributaries of Chindwin most rivers of Nagaland 2 rivers of Mizo and Manipur Tributaries of Barak

separated by numerous small rivers Tributary of Meghna The eastern hills and mountains

Loktak lake Mizoram ( Molassis Basin )

Low hills - inhabited by various tribals - practising Jhum surrounded by mountains in manipur made of soft unconsolidated deposits

3200 km ( E to W ) 150-300 km alluvial deposits brought by systems of Indus Ganga Brahmaputra length width formed by Majuli - largest inhabited in the world Sunderbans : world’s largest delta some the largest deltas in the world The northern Plains have ch/ feature of mature stage of fluvial erosional and depositional landforms like braided channels water divide b/w Indus and Ganga system Haryana and Delhi major zones riverine islands eg. Brahmaputra plain sand bars right turn to south at Dhubri Brahmaputra alluvial plains periodic floods and shifting river courses forming braided streams

¥ Here most of the rivers and streams re-emerge without having any properly demarcated channel Mnemonics : BHaag Tilkha BHA-KH! ( capital letters stand for the 4 zones ) Geo XI (2) - Ch. 2 - page 6 Hazaribagh Eg. Bhima fault - recurrent seismic WG EG Palamu activities more continuous discontinuous and low hills Ranchi series of patland plateaus higher elevation Low hills Malwa undergone recurrent phases of most of the Peninsular highly eroded by rivers like Coimbatore upliftment and submergence rivers originate here mahanadi , godavari , accompanied by crustal krishna , kaveri Karnataka faulting and fractures

NE plateau

Deccan plateau The peninsular plateau 3 Broad groups Central Highlands NW : complex relief of tors ravines and gorges

block mountains

Imp. physiographic rift valleys chambal bhind morena features spurs bare rocky structures

series of hummocky hills

wall like quartzite dykes

natural sites for water storage Geo XI (2) - Ch. 2 - page 7 Vindhya many of Yamuna originate here N NE

tributaries Kaimur

marble slope towards Banas only tributary of chambal metamorphic process originating from Aravali slate ⇒ in geological history Central Highlands gneiss barchans : crescent Jaisalmer Boundary shaped sand dunes series of scarped plateaus highly denuded longitudinal and sand ridges Satpura relict mountains discontinuous ranges max rain from SW monsoon

coal limestone meghalaya plateau rich in mineral reserves iron uranium highly eroded surface sillimanite NE plateau Rajmahal hills eg. Cherrapunji → barely rocky surface devoid of any permanent karbi anglong plateau Origin of Himalayas → NE Huge fault created b/w later - filled by rivers vegetation cover movement of Indian Plate Meghalaya plateau

vegetation cover : low but surface features - carved by extension of peninsular plateau physical weathering and wind actions due to aridity ⇒ underlying rock structure rain: < 150 mm barchans climate : arid ⇒

Indian desert ( Marusthali ) topography N : sindh sloping towards longitudinal dunes : more prominent near Indo-Pak boundary

S: Rann of Kachchh under sea ( mesozoic era ) luni water bodies land features rivers ephemeral mushroom rocks evidence : wood fossils park at streams disappear into brackish water : oasis ( mainly in south ) Aakal and marine deposits around lake/playa main source of salt shifting dunes brahmsar ( near jaisalmer ) Geo XI (2) - Ch. 2 - page 8 fishing

Malabar Coast Distinguishing features Kayals (backwaters) navigation N and S : Broad tourism breadth Punnamada kayal - Nehru Trophy Vallamkali ( boat race ) N : Northern Circar mid : narrow Coastal Plain ( CP) S : Coromandel coast

rivers passing dont form any delta W E rivers passing form well developed deltas Dwarka : a part of WCP ⇒ submerged emergent coast

Goan coast also called as Kannad WCP → AW narrow belt broader

continental shelf upto 500 kms into sea ⇒ difficult natural conditions for development of ports/harbours for devp of ports/harbours ⇒ lesser no. of ports

storm beaches consisiting of Barren island : only active volcano in India unconsolidated pebbles , shingles , cobbles and boulders on the eastern board

entirely built of coral deposits The Islands some mountains : volcanic origin Kavaratti Island : administrative HQ elevated portions of submarine mountains

Pitti island coastal line - some coral deposits ( uninhabited ) : Bird sanctuary rain : convectional Earlier known as Laccadive , A & N islands Minicoy and Aminidive . Lakshdweep Name changed in 1973 vegetation : equatorial type

280-480 km off 2 principal groups KL coast 36 islands - 11 inhabited 572 islands Ritchie’s Archipelago Labrynth island

largest island : Minicoy