India Physical Environment Chapter 2 Structure And Physiography

The characteristics of Arunachal Himalayas:

To the northwest of the Aravali hills lies the Indian desert.

Following are the features of Deccan Plateau:
(i)This is bordered by the Western Ghats in the west, Eastern Ghats in the east and the Satpura, Maikal range and Mahadeo hills in the north.

(ii)Western Ghats are locally known by different names such as Sahyadri in Maharashtra, Nilgiri hills in Karnataka and Tamil Nadu and Anaimalai hills and Cardamom hills in Kerala.

(iii)Western Ghats are comparatively higher in elevation and more continuous than the Eastern Ghats. Their average elevation is about 1,500 m with the height increasing from north to south. ‘Anaimudi’ (2,695 m), the highest peak of Peninsular plateau is located on the Anaimalai hills of the Western Ghats followed by Dodabetta (2,637 m) on the Nilgiri hills.

(iv)Most of the Peninsular rivers have their origin in the Western Ghats. Eastern Ghats comprising the discontinuous and low hills are highly eroded by the rivers such as the Mahanadi, the Godavari, the Krishna, the Kaveri, etc.

(v)Some of the important ranges include the Javadi hills, the Palconda range, the Nallamala hills, the Mahendragiri hills, etc. The Eastern and the Western Ghats meet each other at the Nilgiri hills.

Karewas are the thick deposits of glacial clay and other materials embedded with moraines.
The Kashmir Himalayas are famous for Karewa formations, which are useful for the cultivation of Zafran, a local variety of saffron.

There are two major island groups in India – one in the Bay of Bengal and the other in the Arabian Sea. The Bay of Bengal island groups consist of about 572 islands/islets.
(i)These are situated roughly between 6°N-14°N and 92°E -94°E. The two principal groups of islets include the Ritchie’s archipelago and the Labrynth island. The entire group of island is divided into two broad categories – the Andaman in the north and the Nicobar in the south. They are separated by a water body which is called the Ten degree channel. 
(ii)The islands of the Arabian sea include Lakshadweep and Minicoy. These are scattered between 8°N-12°N and 71°E -74°E longitude. These islands are located at a distance of 280 km-480 km off the Kerala coast. The entire island group is built of coral deposits.

1. Northern mountains

2. The Great plains.

3. Peninsular plateau.

4. Coastal plains and Islands.

5. Indian desert

The three mountain peaks are :

(i)Everest (8848 m)
(ii)Kanchenjunga (8598 m)
(iii)Annapurna (8078)

The three types of sand dunes of the Thar desert are :

(i)Longitudinal 
(ii)Barchans 
(iii)Transverse

The ports are:
(i)Kandla
(ii)Mazagaon
(iii)JLN port Navha Sheva
(iv)Marmagao
(v)Mangalore
(vi)Cochin

The central Highlands:
(i)They are bounded to the west by the Aravali range. The Satpura range is formed by a series of scarped plateaus on the south, generally at an elevation varying between 600-900 m above the mean sea level. This forms the northernmost boundary of the Deccan plateau.
(ii)The extension of the Peninsular plateau can be seen as far as Jaisalmer in the West, where it has been covered by the longitudinal sand ridges and crescent-shaped sand dunes called barchans.
(iii)The general elevation of the Central Highlands ranges between 700-1,000 m above the mean sea level and it slopes towards the north and northeastern directions.
(iv)Most of the tributaries of the river Yamuna have their origin in the Vindhyan and Kaimur ranges. Banas is the only significant tributary of the river Chambal that originates from the Aravalli in the west.
(v)An eastern extension of the Central Highland is formed by the Rajmahal hills, to the south of which lies a large reserve of mineral resources in the Chotanagpur plateau.

2. It lies between the Bay of Bengal (east) and the Eastern Ghats (west). Expansion : West Bengal → Kanyakumari.

3. Its width varies between 60 to 100 kilometres.

4. North circar (Andhra Pradesh) and Coromandal Coast (Tamil Nadu) are its two subdivisions.

5. Four fertile deltas formed here by the rivers are- Mahanadi, Godavari, Krishna and Kaveri.

1. Features of Lakshadweep :

(i) It is a group of 36 smaller coral islands with total area of 32 sq. kilometres.

(ii) Formally, this islands group was known as Laccadive, Minicoy and Amindive islands renamed as Lakshadweep in 1973.

(iii) It lies at a distance of 300 kilometres from the west of Kerala coast.

(iv) These islands are inaccessible and only eleven islands are inhabited.

(v) Headquarter of this Union Territory is located at Kavaratti, famous for numerous species of flora and fauna.

(vi) This groups of islands lies between 8°N-12°N latitudes and 71°E-74°E longitudes.

2. Features of Andaman and Nicobar Islands :

(i) This U.T. is located in Bay of Bengal.

(ii) Two hundred islands of this group are spread over an area of 350 km. There are 19 islands in the Nicobar group.

(iii) Almost all islands of this group are inhabitable.

(iv) Here exists densely forested land and abysmal sea.

(v) These islands are like beads in a garland.

(vi) Here is equatorial climate, wildlife and ample quantity of natural resources.

(vii) An active volcano is located in one of its barren islands. Eruptions were seen on 10 April, 1991.

(viii) Headquarter of this islands group is located at Port Blair.

(ix) These lie between 6°45'N and 14°N latitudes and 92°E and 94°E longitudes.

(i)Fresh water lake - Dal and Wular

1. In the first stage, the uplift of the central Himalayan axis took place in Oligocene period about 150 million years ago.

2. The second uplift took place during the Miocene period when Potwar region of West Pakistan was uplifted.
3. The third stage was marked by the folding of the Siwalik in the post-Pliocene period about 100 million years ago.

Some geologists believe that Himalayas are still rising. It proves the gradual rising of the Himalayas.

A belt of marshy ground and vegetation on the lower parts of the alluvial fans.

1. Bist Jalandhar Doab : Between the Satluj and the Beas.

2. Bari Doab : Between Ravi and the Chenab.

3. Chaj Doab : Between the Chenab and Jhelum.

4. Sind Sagar Doab : Between Chenab and Indus river.

1. The occurrence of Karewas, the tilted bends of the lake deposits of Kashmir at altitudes of 1500--1800 meters on the flanks of Pir Panjal Range.

2. The fossils of post-tertiary mammals have been found in the sub-Himalayan foot- hills, pointing continuity of upliftment during the Pleistocene times.

3. The archaeologists have collected curious stone tools, representing the Paleolithic times, early man in the terraces of Himalayan rivers, such as the Sohan, and in the Siwalik deposits near Chandigarh. The Siwaliks are believed to be the latest upliftment of the Himalayas.

1. The western coastal plains have narrow alluvial margin interspersed by hilly terrains.

2. This coast has beautiful lagoons in the Malabar coastal area and many estuaries in the Konkan coast.

3. This coast has been divided in to Gujarat and Konkan plains and Malabar coast. This coast is dominated by the S.W. winds.
Eastern Coastal Plains :

1. The eastern coast has a wide plain with well developed deltas of the rivers.

2. The eastern coast has well formed deltas by the major rivers and a few lagoons.

3. The eastern coast plain has two broad subdivisions i.e., Coromandal and North Circar plains. These are dominated by S.W monsoon as well as North-West monsoon winds. These winds have cyclonic disturbances in winter.

‘E’ stands for Shivaliks or Outer Himalayas.

‘F’ stands for Indo-Gangetic plains.

16 = Nilgiri Hills 23 = Satpura Hills

At Haridwar he will enter the plains.
(i)At several places the river forms the meanders.
(ii)In central plain the river forms the oxbow lakes and braided streams.
Finally he will reach swampy and marshy delta which is formed by Ganga.

The valley plains are formed by the alluvial deposits brought by the rivers.

(i)Bhabar: It is a narrow belt ranging between 8 km and 10 km parallel to Shiwalik foothills at the break up of the slope.

(ii)Tarai : South of Bhabar is the belt of Tarai with a width about 10 to 20 km where the most of rivers re-arrange without having any properly demarcated channel creating a marshy and swampy condition known as Tarai.

(iii)Bhangar : It is composed of old alluvium and forms the alluvial terraces above the level of the flood plains.

(iv)The Khadar : The flood plain which has newer alluvium is called Khadar. A newer layer is deposited by river floods every year.

(v)Delta : The mouth of mighty rivers also form the delta. Sunderban delta is an example.

Characteristic features : 1. The whole region is forested and is inhabited by the Gonds, Santhals, Oraons and Bhils.

2. It contains the Aravalli range, the east Rajasthan uplands, the Madhya Bharat upland and Bundelkhand upland, the Malwa Plateau, the Vindhyan scarpland and the Narmada valley.

3. The first four form the northern part of the highlands and the last four the southern highlands.

1. It has been learned that the Himalayas had been formed by the internal forces in various phases of movements. It had been uplifted from the great Geosyncline known as Tethys sea in the folded form. These uplifted ranges had been denuded by the weathering and the other agents of changes such as rivers and glaciers. These agents of changes carved the minor physical features such as gorges, U-shaped valleys, hanging valleys and ridges. The Indus gorge is the result of erosion and weathering.

2. Many U-shaped and hanging valleys found in this region are the result of erosional work of glaciers and ice.

3. The high order complexities in the relief features of the Himalayas were achieved by the various processes of weathering and cycle of erosion.

4. The fertile valley of Kashmir represents the depositional work of the agents of changes.

5. The rivers rising from Himalayas such as Ganga, Indus and their tributaries are busy is carving the minor physical features.

6. The snow-capped peaks of Himalayas represents the work done by earth movements.

The Himalayas can be divided into four parts : 1. Northern Kashmir Himalayas, 2. Main Himalayas, 3. Offshoots of the Himalayas 4. Regional Divisions.

1. Northern Kashmir Himalayas : The north-western part of the Himalayas is known as the Kashmir Himalayas. Their breadh is about 40 to 50 kilometres.Karakoram, Ladakh, Zaskar and Kailash are the main ranges of the Kashmir Himalayas. There are many high peaks in these ranges.

2. Main Himalayas : The main Himalayas consist of three parallel mountain ranges. We can describe them as under :

(a) Greater Himalayas (Himadri) : This range spread in a west-east direction from the Indus to the Brahmaputra. Mount Everest (8,848 metres), the highest peak of the world is in this range. Zojila, Jailpala and Lingshila are some of the important passes of this range. Many glaciers like Gangotri and Yamunotri originate from these snow-covered mountains. The Bhagirathi which further comes to be known as River Ganga originates from this (Gangotri) glacier.

(b) The Middle, Lesser or Himachal Himalayas : This range spreads in the south of the Greater Himalayas. It runs parallel to Himadri form east to the west. The average height of this range is 3500 to 4500 metres and its breadth is 60 to 80 kilometres. Hill stations of Shimla (H.P.), Mussoorie, Nainital, Ranikhet, Kausani (all in Uttaranchal State) are located on this range.

(c) Siwaliks or the Outer Himalayas : The average height of this range is 900 to 1200 metres and breadh is 10 to 50 kilometres. Altitudinal variation exists here because this range is broader enough than average (i.e. 10-50 kms) in Himachal, Punjab and Kashmir states.

3. Offshoots of the Himalayas : The

Himalayas turn to the south on the eastern and western flanks. They are called eastern and western Himalayas.

(a) Eastern Himalayas : These consist of the famous hills of Patkai, Naga and Mizo. These form Purvanchal. These are very low hills and fully covered with forests and bushes.

At the extreme east, there are the Jaintia, the Khasi and the Garo hills.

(b) Western Himalayas : These consists of Suleman and Kirthar ranges. Khyber, Bolan and Tochi passes exist here.

4. Regional Divisions of the Himalayas :

Regionwise expansion of the Himalayas is classified as –the Himachal Himalayas, the Garhwal and Kumaon Himalayas, the Nepal Himalayas and the Assam Himalayas.

D.

C.

C.

A.

2. It is 8-16 km wide.