PHYSIOGRAPHY OF INDIA
PHYSIOGRAPHY OF INDIA
Physiography deals with study of surface features i.e. reliefs and landforms of the Earth. Both endogenic and exogenic forces continuously operate to create and shape the present landforms.
The Indian landmass can be divided into following broad physiographic units:
- Himalayas or northern mountains
- The Great Plains of north India
- Peninsular plateau
- Coastal plains
The physiographic units can be shown in other way also as given in following diagram.
HIMALAYAN MOUNTAINS | GREATER HIMALAYA/ HIMADRI
- The Himalayas are the youngest and loftiest mountain chains in the world. They run in north-west to south-east direction, in the form of arcuate shaped curve which is convex to the south. They stretch for 2400 km in length. Width-wise they range from 500 km in Kashmir to 200 km in Arunachal Pradesh. On southern side, the Himalayas rise sharply to great heights within few kilometers from the Plains while northern boundary merges imperceptibly with the high altitude Tibetan plateau.
- On the western side, Himalayas extend into Hindukush, Sulaiman & Kirthar mountain ranges. On eastern side, Himalayan ranges in the north-east India merge with Arakan Yoma ranges of Myanmar, Thailand etc. On the northern side, Himalayas merge with the mountain ranges of Central Asia at a knot like structure called the Pamir plateau.
- The Himalayas are characterized by complex geological structure, high attitude, huge glaciers, deeply dissected topography, youthful drainage, rich temperate forests in subtropical latitudes, etc.
ORIGIN & DEVELOPMENT
- About 120 million years ago, there was a super continent called Pangaea whose northern part was called Angaraland and Southern part Gondwanaland. Both were separated by a long, narrow and shallow sea i.e. a geosyncline called Tethys Sea. As per theory of plate tectonics, the Indian Plate of Gondwanaland moved northward across the Tethys sea and thrust into Eurasian plate of Angaraland.
- As a result, the sediments accumulated in Tethys Sea (brought by rivers) were compressed, squeezed and series of folds were formed one behind the other, giving birth to folded mountains of Himalayas. Indian plate is still moving northwards at the rate of 5 cm/year and pushing into rest of Asia, thereby constantly increasing the height of Himalayas. Thus as the process of mountain building is still going on, the Himalayan region frequently experiences earthquakes such as in Sikkim 2011, Pakistan January 2011.
DIVISION OF HIMALAYAS | GREATER HIMALAYA/ HIMADRI
- Himalayas can be studied in regional manner by making politico-cultural divisions. Various features of Himalayas in a particular region are then grouped together and studied.
- Kashmir or Northwestern Himalayas
- Himachal and Uttaranchal Himalayas
- Nepal Himalayas or Mahabharat ranges
- Darjiling and Sikkim Himalayas
- Bhutan Himalayas
- Arunachal Himalayas
- Eastern Hills and Mountains.
- On the basis of relief, alignment of ranges and other geomorphological features, the Himalayas can be divided into the following sub-divisions:
- Greater Himalayas or Himadri
- Middle Himalayas or Himachal
- Lesser Himalayas or Outer Himalaya or Shivaliks
- Hills of the North-East or Purvachal
GREATER HIMALAYA/ HIMADRI
- This is also known as central axial range. These are of highest elevation with heights above 6000 m and have width of about 25-40 km. The mountains are asymmetrical with steep southern slope and gentle northern slope merging with Tibetan plateau. They abruptly turn southward at the syntaxial bends (hairpin like) of Nanga Parbat in the west and at Namcha Barva in the east. More than 100 peaks have a height of more than the average height of the range.
- The highest peak of the world, Mount Everest, (8848 m) is situated in this range. Kanchenjunga, Makalu, Dhaulagiri, Annapurna are some of the other peaks having a height of more than 8000m. Kanchenjunga is the highest peak of Himalayas in India. Several passes in these ranges are part of ancient ‘Silk Route’ of trade. Karakoram, Qara Tagh, Zozi Ia, Burzil (J&K), Bara Lacha La, Shipki Ia (Himachal Pradesh), Thaga Ia, Niti, Lipu lekh (Uttarakhand), Nathu la, Jelep Ia (Sikkim), Patkai, Bomdi la (Arunachal Pradesh) etc are important passes from trade and strategic point of view.
- The Greater Himalayan range is snow clad throughout the year. There are a number of large and small glaciers. E.g. Gangotri and Yamunotri. After melting of snow and ice, their water falls in the rivers of northern India making them perennial throughout the year.
- With elevations above 3500 to 4500 m ASL and 60-80 km width, they present hogback topography having steep, bare southern slopes and gentle forest covered northern slopes. The important ranges include Pir Panjal in Jammu and Kashmir, Dhaula Dhar in Himachal Pradesh, Masoorie and Nag Tibba in Uttaranchal and Mahabharat range in Nepal. Pir Panjal, Golabghar, Banihal (Jammu-Srinagar Highway) are important passes.
- Between middle and greater Himalayas are located some broad synclinal valleys — beautiful, fertile and densely settled such as Kashmir valley between Pir Panjal and Greater Himalaya, Kangra valley between Dhauladhar and Greater Himalayas and and the Kathmandu valley in Mahabharat Ranges. Also the majority of Himalayan hill resorts such as Shimla, Kullu, Manali, Massoorie, Nainital, Dalhousie, McLeodganj etc. are located in middle Himalayas. Some of the most beautiful lakes such as Nainital, Bhimtal, Chandertal, etc. are located in these ranges.
LESSER HI MALAYAS/SHIWALIKS/OUTER HIMALAYAS
- The Shiwaliks are outermost range with similar hogback looks. They have average elevation of 600 m and width of 15-50 km. Shivalik ranges have been formed much later by the accumulation of sediments from Greater and middle Himalayas brought about by the rivers. In course of time, the earth movements caused folding of these relatively fresh deposits of sediments, giving rise to the least consolidated Siwalik range.
- They are covered by dense forests aided by the orographic rainfall of monsoon and at the same time suffer from great erosion by the Himalayan Rivers.
- The longitudinal valleys between Shivaliks and Middle Himalayas are called as ‘duns’ in the west. e. g. Dehradun, duns of Udhampur and Kotli. Shivalik ranges are conspicuously absent in eastern Himalayas and in their place low rolling hills known as ‘duars’ are present. These duars of West Bengal and Sikkim are known for their tea garden plantations and its scenic beauty.
- The range north of the Himadri in Jammu and Kashmir and running parallel to it is called the Zaskar range. North of Zaskar range is the Ladakh range. The river Indus flows towards northwest between Zaskar and Ladakh range.
- North of the Ladakh range lie the Karakoram. Karaoram Mountains also called Krishnagiri form India’s frontier with China, Turkmenistan, Afghanistan and Pakistan. K2 (in Pakistan occupied Kashmir) is the highest peak in these ranges & 2nd highest one in the world (8611m). Ladakh plateau is the highest plateau -5300 m ASL- of India having physiography of ‘cold desert’. PHYSIOGRAPHY OF INDIA
- Near Dihang gorge in Greater Himalayan ranges where Brahmaputra enters into India, the Himalayas take a sudden southward turn and run in north-south direction. They form a frontier initially between India and China and then India and Myanmar.
- These ranges include Patkai Bum, Naga hills, Barail hills, Manipur hills, Mizo hills. Although comparatively low in height (2000-3000 m), these hills are forbidding because of rough terrain, dense forests and swift streams. It should be noted that the hills of Garo, Khasi aand Jaintia in Meghalaya are structurally part of peninsular plateau and not the Himalayan ranges.
GLACIERS OF HIMALAYAS | PHYSIOGRAPHY OF INDIA
- All the important rivers of Indian subcontinent are fed by Himalayan glaciers. Karakoram ranges have half of the snow bound area of Himalaya and some of the largest glaciers outside polar and subpolar regions such as Siachen glacier (75 km long).
- Baltoro, Biafo, Hispar, Chogo Lungma. The Sona Pani and Gangri glaciers are present in Pir Panjal while In Kumaon Himalayas Gangotri, Kedarnath, Milam, Pindari are important glaciers. Central Himalayas in Nepal have several large glaciers like Rongbuk, Khumbu, Annapurna, Zemu, Kanchanjunga etc.
- These glaciers form the sources of perennial rivers of the subcontinent. It is feared that under the effect of climate change and global warming, they are fast receding and melting down.
- SIGNIFICANCE OF HIMALAYAS | PHYSIOGRAPHY OF INDIA
Himalayas are not only the physical barrier; they are also a climatic, drainage and cultural divide. Himalayas contribute to the genesis of monsoon winds as well as to the precipitation by obstructing northward moving monsoon winds. The high altitude of Himalayas also blocks cold continental air masses of Central Asia from entering India. They also act as defence barrier against outside invaders.
Himalayas are the main source of north Indian rivers which provide water for drinking, irrigation, creation of reservoirs and hydel power. The fertile alluvial soil formed by weathering and erosion of Himalayan ranges is deposited by the rivers into the Great Plains. Himalayan slopes support crops like barley, maize, potato, and fruits of temperate climate.
Himalayas are home to rich variety of flora and fauna including medicinal herbs. In fact they are one of the biodiversity hotspots of the world. They also have important minerals reserves like petroleum, limestone, precious stones, etc. Himalayas have been favoured places of nature, leisure and religious pilgrimage. PHYSIOGRAPHY OF INDIA
GREAT PLAINS OF NORTH INDIA
- The Great Plains or Indo-Gangetic-Brahmaputra plains are the largest alluvial tract in the world stretching for 3200 km from the mouth of Indus to the Brahmaputra valley in the east and to the mouth of Ganga southward. Its length in India is 2400 km and width of around 500 km in Punjab narrowing down to 100-60 km in Assam.
- The area of this plain is more than 7 lakh square km. Their northern boundary is well defined by Shivalik foothills while southern boundary merges with irregularly shaped peninsular edge. This aggradational or depositional plain is characterized by extreme horizontality & negligible slope (10-25 cm/km). Frequent floods and changing courses of rivers deposit fresh layers of fertile silt on the floodplains.
ORIGIN | PHYSIOGRAPHY OF INDIA
The Great plains are formed by infilling of foredeep between northward moving Indian peninsula and Himalayas-Asian Continental mass. The infilling has been done by prolonged deposition of detritus (sediments) brought by Himalayan and peninsular rivers from their erosive activity. The rivers have been depositing their sediments in this plain over millions of years. Therefore, the depth of alluvium in this plain ranges from quite a few hundred metres to as much as 2000 to 3000 m.
PHYSIOGRAPHIC FEATURES/FEATURES OF THE PLAINS
- The heavy boulders, gravels and coarse sediments flown in by the Himalayan Rivers are deposited at the foothills of Shivalik Mountains. The plains formed by these coarse sediments are called Bhabar or piedmont plains. Due to high porosity small river streams disappear in Bhabar tract.
- These streams re-emerge south of Bhabar forming a marshy tract called Tarai forests. Today the Tarai region has been reclaimed for agriculture & now there are no forests. Further South of Tarai is the alluvial plain formed by the deposition of alluvium or silt by the rivers. The older alluvium located at relatively higher ground away from the river course is called Bhangar plains. It contains calcium carbonate nodules called Kankars.
- The areas of newer alluvium along the course of rivers are called Khadar or betlands. Every year during floods fertile silt is deposited in Khadars. The Brahmaputra plains are known for their riverine islands and sand bars.
- The alluvial plains have characteristic features of mature stage of fluvial erosional and depositional landforms such as sand bars, meanders, oxbow lakes and braided channels. Reh, Kallar, Bhur are other micro features of plains. Most of these areas are subjected to periodic floods and shifting river courses forming braided streams.
REGIONAL DIVISIONS | PHYSIOGRAPHY OF INDIA
- The Gangetic plain is the largest physiographic unit of Northern plains. The upper Gangetic plain includes the upper Ganga-Yamuna doab. Plain to the east of doab is called Rohilkhand plains. Further south-east is Avadh plain which merges into middle Gangetic plains. The middle Gangetic plain is drained by Ghaghara, Gandak & Kosi rivers and includes their doabs. Gandak-Kosi doab is known as Mithila plain while the area lying south of Ganga & west of Son River in Bihar is known as Magadh plain.
- The lower Ganga plain lies in West Bengal. The northern part of this plain is formed by sediments deposited by Tista, Jaldhaka & Torsa. Besides this area also includes the Darjiling Tarai known as Duars and the Barind plains which extend from Kosi-Mahananda belt to Sankosh River in the east. The physiographic features observed are mentioned above. Apart from those features this region has meanders, oxbow lakes, river bluffs etc. The delta plains of Bengal are actually extension of Khadar lands. In delta region low lying marshy areas or alluvial lakes are called bills while uplands are called Char.
- The Brahmaputra plain is surrounded by mountains on all sides except west. Many small rivers from Himalayas debouch in the plains, particularly on northern bank. This has led to formation of marshy lands, lakes, river islands, dense forests and rich wild life in Brahmaputra plains. Every year vast tracts of these plains are inundated by the flooded rivers.
- Great Indian Desert or Thar Desert, an extension of Great Plains, is present to the east of Aravallis. Marusthali — the western part of desert is covered with shifting sand dunes while eastern part called as Rajasthan Bagar is semi-arid rocky plain. Rohi is the fertile agricultural tract in South-West of Aravallis with seasonal streams originating from the mountain.
- The adjacent Punjab-Haryana plain is divided into many doabs i.e. area between two rivers. It is dominated by Satluj-Yamuna river systems, their levees locally called ‘dhaya’ and Khadar lands locally called as ‘bet’. Many small streams known as chos descend from adjacent Shivaliks into these plains. They have significantly eroded the adjacent lands such as in Hoshiarpur. To the south of Satluj river lays the Malwa plain of Punjab and Haryana. PHYSIOGRAPHY OF INDIA
SIGNIFICANCE OF PLAINS | PHYSIOGRAPHY OF INDIA
The Great Plains harbour intensive agriculture based economy, highest population densities and dense network of roads and railways. The plains of Punjab, Haryana and Western UP are called Granary of India because of Green Revolution. Hindu, Muslim, Sikh, Buddhist cultures and their religious places have flourished on these plains.
- PENINSULAR PLATEAU
- Peninsular India is the oldest and largest physiographic unit of India. Its average elevation is of 600-900 m. It’s a roughly a triangular block with apex pointing southward. Delhi ridge — an extension of Aravalis – in the northwest, the Rajmahal hills in the east, Gir range in the west and the Cardamom hills in the south constitute the outer extent of the peninsular plateau. However, an extension of this plateau is also seen in the northeast, in the form of Shillong and Karbi-Anglong plateau.
- The plateau is bordered on all sides by the hill ranges. The entire plateau is an aggregation of several smaller plateaus and hill ranges interspersed with river basins and valleys. While the general slope of the plateau is from west to east with rivers draining into Bay of Bengal, the base of the plateau slopes northward with Chambal and Son valleys draining in Yamuna and Ganga rivers. The plateau has senile topographic features due to prolonged erosion like shallow river valleys and small rounded hills.
- The plateau is also characterized by presence of black cotton soil in its western parts. Geologically the plateau is regarded to be stable, although it has seen some changes like recurrent phases of upliftment and submergence accompanied by crustal faulting and fractures. E.g. Narmada – Tapi rift valley formation and eruption of basalt lava through the fractures.
HILL RANGES OF PENINSULA | PHYSIOGRAPHY OF INDIA
- THE ARAVALLIS
It is relict of one of the oldest fold mountains of the world. At present it is seen as discontinuous ridges from Delhi to Ajmer and rising up to 1722 m (Gurushikhar peak in Mt. Abu) thence southward. Pipli Ghat, Haldi Ghat, Dewair, etc. are important passes.
- VINDHYAN RANGES
They rise as an escarpment running parallel to Narmada-Son Valley. Most of them are made up of sedimentary rocks of ancient ages: They continue eastward as Bhanrer-Kaimur ranges. These mountains act as watershed between Gangetic and peninsular river systems.
- SATPURA RANGE
Satpura ranges run parallel between Narmada and Tapi, parallel to Maharashtra – MP border. They include Rajpipla hills, Mahadev hills and Maikala range. Dhupgarh (1350 m) near Panchmarhi, Astamba Dongar and Amarkantak are important peaks. PHYSIOGRAPHY OF INDIA
- WESTERN GHATS (SAHYADRI)
It is a faulted part of the Deccan plateau running parallel from Tapi valley to little north of Kanniyakumari (1600 km). The western slope is like an escarpment risinng sharply from western coastal plains while eastern slope merges gently with plateau. The Sahyadris form a real watershed of peninsula. Godavari, Krishna and Kaveri rivers originate in Western Ghats. In Karnataka, Sahyadri runs quite close to the coast. Kudremukh (1892 m), Kalsubai (1646 m), Mahabaleshwar and Harish Chandra are important peaks. The passes Thal ghat, Bhor Ghat (both in Konkan), Palghat Gap (between Kerala and Tamil Nadu) connect coastal plains with interior plateau. The Anaimudi (2696 m) is highest peak in the whole south India from where three ranges radiate in three directions — Cardamom hills to the South, Anaimalai to the north and Palni to the north east.
- EASTERN GHATS
Eastern Ghats is the discontinuous chain of isolated, broken hills. In Odisha, they are known as Maliya and Madugula Konda ranges with Mahendragiri as the tallest peak (1501m). In Andhra Pradesh these are known as Nallamalai & Palkonda ranges. Further southwards these are present as detached low hills — Javdi, Shevroy, Panchaimalai, Sirumalai, Varushnad hills.
The Nilgiri is the meeting point of Western Ghats, Eastern Ghats and southern hills. Dodabetta (2637 m) is its highest peak and Udhagmandalam (Ooty) is a nearby hill station.
THE PLATEAUS OF PENINSULA | PHYSIOGRAPHY OF INDIA
- Marwar Upland — It lies to the east of Aravalis in Rajasthan. It is a rolling plain carved by the Banas River.
- Madhya Bharat Pathar — To the east of Marwar upland it comprises ravines (badlands) of Chambal and thick forests.
- Bundelkhand Upland — It has senile topography comprising small rounded hills of granite, gneiss and sandstones. Because of intensive erosion, semi-arid climate and undulating area it is unfit for cultivation.
- Malwa Plateau — It’s a rough triangle based on Vindhyan hills. It is present between Aravallis and the scarps overlooking Bundelkhand.
- Baghelkhand — East of Maikal range is the Baghelkhand. It comprises Vindhyan Sandstones, Son river basin and thick forests.
- Chhota Nagpur Plateau — It includes Jharkhand, northern Chattisgarh and Purulia in West Bengal. It has average elevation of 700 m comprising Archean rocks, Gondwana rocks and Deccan lavas. This plateau consists of series of step like sub-plateaus (locally called as patlands — high level laterite plateau) such as Hazaribagh and Ranchi plateau. Rajmahal hills are northeastern projection of Chhota Nagpur Plateau. Numerous rivers flow radially downward from this plateau making number of waterfalls. Chhota Nagpur is a mineral rich plateau.
- Meghalaya/Shillong Plateau — It is separated from peninsular rock base by Garo-Rajmahal gap. This gap was formed by downfaulting & at present filled with alluvium of Ganga & Brahmaputra. The Meghalaya plateau has Garo, Khasi, Jaintia and Mikir (Rengma hills). It slopes down to Brahmaputra valley in north & to Surma & Meghana valley in south. The portion between Meghalaya and Purvanchal ranges is occupied by North Cacher hills. Shillong (1961m) is the highest point.
- Deccan Plateau — It’s the largest unit of peninsula. It can be subdivided as follows: Maharashtra plateau has typical Deccan Trap topography underlain by basaltic rock. The lava derived black colored regur is typical soil of this plateau. The Kamataka plateau is divided into the western hilly country region of Malnad and the eastern plains of Maidan. Both Karnataka & adjacent Telangana plateau in Andhra Pradesh have Archean, Dharwar and Cudappah rocks. The Deccan plateau is drained by the shallow and broad basins of Godavari, Krishna and Kaveri rivers. PHYSIOGRAPHY OF INDIA
- Chattisgarh Plain is the only plain in peninsula. It’s a saucer depression drained by upper Mahanadi course. It lays between Maikala range and Odisha hills. It is occupied by dense Dandakaranya forests.
SIGNIFICANCE | PHYSIOGRAPHY OF INDIA
- The peninsular landmass is geologically very rich and yields a variety of metallic and non-metallic minerals. The basaltic rocks results in fertile black Regur soil giving good yield of cotton and sugarcane, while the areas of Sahyadri are known for tropical crops such as spices, tea, coffee, banana, alphonso mangoes etc. The hydel power potential of peninsular rivers is limited although by seasonal nature of these rivers.
- The biodiversity hotspots of Western Ghats and dense central Indian forests sustain varied flora and fauna. The Vindhyas have acted as natural watershed between north and south India. The Vindhya and its dense forests have acted as a physical barrier between the Northern Plains and the Peninsula, as a result of which the cultural traits of area south of Vindhyas are different than the Northern plains. Even within peninsula there are regional variations in cultures commensurate with geographical variations of hills, rain shadow regions and plateau region.
- There are number of hill resorts in peninsula such as Mount Abu, Panchamarhi, Lonavala, Mahabaleshwar, Matheran, Ooty, Kodaikanal etc. The peninsula harbours lesser population than the Northern plains because of its rugged terrain and water scarcity. But the presence of mineral deposits and availability of ports on the adjacent coasts have helped change the economic potential of the region.
- COASTAL PLAINS | PHYSIOGRAPHY OF INDIA
The total coastline of India runs for 7517 km and that of the peninsula is 6100 km. between peninsular plateau and the sea.
- Western Coastal Plain: These are straight (1500 km) narrower (10-25 km) and wetter than their eastern counterpart. The northernmost section, Rann of Kachchh comprising Great Rann and Little Rann, is a salt soaked plain subject to marine inundations. Kathiawar peninsula contains volcanic hills made up of basaltic lava (Gir and Mandav hills). The coastal plains from Daman to Goa are called Konkan Coast (500 km) which is generally flat and composed of basaltic trap rocks. Karnataka coast runs from Goa to Cannanore. It is the narrowest part of western coastal plains. From Cannanore to Cape Camorin (Kanniyakumari) for 500 km runs the Malabar Coast. It has characteristic lagoons or backwaters locally called Kayals such as Asthamudi and Vembanad. Many small rivers descend from Western Ghats making a chain of waterfalls throughout the length of Sahyadris. The western coast being more indented than eastern coast has more number of natural harbours.
- Eastern Coastal Plains: These are wider but drier resulting in shifting sand dunes on its plains. The major peninsular rivers have formed thick alluvial deltas which are very fertile. The coast belt from Kanyakumari to Godavari delta is known as Coromandel Coast while coastal tract of Odisha is called Utkal Plains. Lake Chilka and Pulicat are famous lagoons while freshwater Kolleru Lake lies between Krishna-Godavari deltas.
- The coastal plains are agriculturally very productive. Western coast grows specialized tropical crops while eastern coasts witnessed green revolution in rice. The delta regions of eastern coastal plains have a good network of canals across the river tributaries.
- Coastal plains are source of salt, monazite and mineral oil and gas as well as centres of fisheries. Although lacking in adequate natural harbours, the coastal plains have number of major and minor ports.
- These ports are centres of commerce and have attracted dense human settlements and are home to the some of the largest cities of the world. The coastal regions of India inhabiting large population is facing the risk of inundation due to probable sea level rise caused by global warming.
- THE ISLANDS | PHYSIOGRAPHY OF INDIA
- Of the total 247 islands of India, 204 are in Bay of Bengal and remaining in Arabian Sea and Gulf of Mannar. The islands in Bay of Bengal are mostly tectonic and volcanic in origin. Andaman Islands are actually the continuation of Arakan Yoma mountain ranges of Myanmar and form an elevated portion of submarine mountains. Barren Island is a dormant volcano while Narcondam Island has extinct volcano. The Andamans are separated from Nicobar Islands by Ten Degree channel while Dancan Passage separates Little Andaman from Great Andaman. Saddle peak (737m) in North Andaman is the highest peak.
- Nicobar Islands are just 147 km away from Sumatra and have coral origin. The Indira point or Pygmalion point in Great Nicobar is southernmost point of India. The Great Nicobar Biosphere Reserve and the Wandoor Marine Biosphere reserve in South Andaman have rare Giant Robber Crabs.
- The Andaman and Nicobar Island have tropical weather moderated by cooling effect of the ocean. Tropical crops such as rice, coconut, arecanut, banana, etc grow here. These islands are abode of many aboriginal tribes such as Onges, Jarwa, Sentinelese etc who are seeing invasion in their traditional way of life and a rapid decline in numbers.
- Lakshdweep and Minicoy Islands in Arabian Sea are coral islands. While the Eight degree channel separates Minicoy Island from Maldives, the Nine degree channel separates Minicoy Island from main Lakshadweep. Kavaratti is the capital of Lakshadweep. While coconut is the main crop on the islands, fishing is main occupation of people. The corals act as good habitat for fishes to lay their eggs.
- Besides these, there are numerous offshore islands in the
- delta regions of great rivers of India e.g. Sagar, New Moore island (mouth of Ganga), Shri Harikota (mouth of Pulikat Lake), Wheeler (Mahanadi-Brahmani mouth), Aliabet (Narmada), etc. On the other hand, islands like Pamban, Crocodile, Adunda (Gulf of Mannar), Elephanta (Mumbai), etc. are tectonic in origin formed due to submergence. The islands are gaining importance because of increasing interest of superpowers in the geopolitics of Indian Ocean.
SIGNIFICANCE OF INDIAN OCEAN | PHYSIOGRAPHY OF INDIA
- Like formidable Himalayas, Indian Ocean also provides for isolating and guarding of human interaction. The Himalayan mountains and Indian Ocean together make it look as if India was planned by nature as an indisputable geographic unit, sharply isolated from the outside world.
- The monsoonal climate of India is also attributed mainly to the salutary effect of Indian Ocean. It is Indian Ocean which makes the southwesterly monsoon winds laden with moisture and therefore causes heavy rainfall.
- As India lies at the head of Indian ocean it helps in establishing trade and communication links with south-east Asia and Oceania on one hand and west Asia and East Africa on the other.
- The islands in the Indian Ocean are geo-strategically located facing the crucial Sea Lanes of Communication which are important from trade and defence point of view.
- The two branches of the ocean wash the western and eastern shores providing great potential for exploitation of deep sea fishing resources. There is a vast potential of lobsters and shrimps in the Indian Ocean.
- Besides fish resources, Indian Ocean also provides for storehouse of non-living India has been accorded the status of Regional pioneer investor in 1987, pursuant to its efforts and progress in identification and assessment of poly-metallic nodules in the central Indian Ocean.
- The significance of Indian Ocean can also be seen in the form of Cultural It helped Indian culture to venture in eastern and western hemisphere with periodic assimilation of their culture in India.