Physical features of India

What do the movements of tectonic plates cause?

The movements cause stresses which cause folding, faulting and volcanic activities.

What are the types of tectonic plate movements?

Convergent boundary, divergent boundary and transform boundary.

What was the Gondwana land? Which countries were a part of it?

The Indian peninsula is the oldest part of the Indian subcontinent as it was part of the Gondwana land. This landmass included countries like India, Australia, South Africa, South America and Antarctica.

Describe the movement of the Gondwana land.

Convectional currents split the crust of the Earth and the Indo-Australian plate was separated from the Gondwana land and the plate moved into the north, Subsequently, the Australian plate got separated from the Indian plate and the Indian plate hit the Eurasian plate.

Describe the formation of the Himalayas.

When the Indian plate hit the Eurasian plate, the sedimentary rocks in the Tethys sea folded to form the Himalayas.

How were the northern plains form?

The formation of the Himalayas made a depression. This depression gradually got filled with sediments by flowing rivers from the mountains in the north and peninsular plateau in the south which led to the creation of the alluvium filled northern plains of India.

What are the most stable and unstable landforms of India?

The peninsular plateau is the most stable and the Himalayan mountains are the most unstable

What are the physiographic divisions of India?

1) The Himalayan mountains.

2) The Northern plains.

3) The Peninsular plateau.

4) The Indian Desert.

5) The Coastal Plains.

6) The Islands.

Introduction to the Himalayan mountains.

They run in a west to east direction, from the Indus to the Brahmaputra.

They are the most loftiest and rugged mountain barriers of the world.

They form an arc which is 2,400km long.

They have a variable width, from 400km long in Kashmir to 150km long in Arunachal Pradesh.

Higher altitude variations in the east than in the west.

The Himalayas consists of three ranges, the "Himadri", "Himachal" and the "Shiwaliks".

The Himadri

Most continuous range.

Loftiest peaks in the world with average height of 6km.

The folds are not symmetrical.

The core is composed of granite.

Perennially snow bound.

There are many glaciers.

The Himachal

Lies to the south of the Himadri.

Known as the lesser Himalayas.

The ranges are composed of highly compressed and altered rocks.

Altitude range from 4.5km to 3.7 km.

Average width is 50km.

Pir Panjal is longest and most importan range.

Another range is Mahabharat range.

Famous valleys like Kangra and Kullu.

Many famous hill stations too.

The Shiwaliks

Width of 10-50km.

Altitude of 0.9km to 1.1km

Ranges are composed of unconsolidated sediments brought down by rivers from main Himalayan ranges.

Valleys are covered with gravel and alluvium.

Longitudinal valley lying between Himadri and Shiwalikks are called the Duns. Some famous Duns are Dehra Dun, Patli Dun and Kotli Dun.

Name some of the tallest peaks of the Himalayas.

Mount Everest in Nepal at about 8,848m and Kanchenjunga in India at 8,598m.

Describe the longitudinal divisions of the Himalayas.

Longitudinal divisions from west to east. These divisions have been separated by rivers.

1) Punjab Himalayas:-Lies between Indus and Satluj rivers.

2) Kumaon Himalayas:-Lies between Satluj and and Kali rivers.

3) Nepal Himalayas:-Lies between Kali and Tista rivers.

4) Assam Himalayas:-Lies between Tista and Dihang rivers.

What comes after the Assam Himalayas?

The Brahmaputra marks the end of the Himalayas at the east. After the Dihang gorge, the mountains bend sharply to the the south and spread along the eastern boundary of India. These are called the Purvachal or eastern hills. They run along the north-eastern states and are mostly comprised of sandstone. The Purvachal has hills like the Manipur hills, Mizo hills and Naga hills.

Introduction to the northern plains.

Formed due to the Indus, Ganga and Brahmaputra with their tribuataries. Alluvial soil. Spreads of 700,000 km^2, 2,400km long and 240-320km broad. Densely populated with rich soil cover and adequate water supply for a very productive part of India. The rivers from the north are involved in depositional work. The velocity of the rivers slowly decrease due to a gentle slope and form riverine islands. In the lower course, rivers split up due to depositions and these rivers are now called distributaries.

Riverine divisions of the northern plains.

Divided into three sections.

1) Punjab plains:-Western part of the plains. Formed by Indus and tributaries. Mostly in Pakistan. Indus and tributaries originate in Himalayas. This section is dominated by doabs.

2) Ganga plains:-Lies between Ghaggar and Teesta rivers. In the states of Haryana, Delhi, UP, Bihar, part of Jharkhand and West Bengal.

3) Brahmaputra plains:-Mostly in Assam, to the west of the Ganga plains.

Relief variation divisions of the northern plains.

The northern plains do have a diverse relief.

1) Bhabar:-The descending rivers deposit pebbles in about 8km- 16km width which lie parallel to the Shiwalik slopes.

2) Terai:-A wet and marshy region. It was once densely forested but it has been cleared to form a place for the refugees of Pakistan.

3) Bhangar:-Largest part of northern plain. Soil contains calcareous deposits locally called Kankar. The younger deposits are renewed every year and are called Khadar.

Introduction to the peninsular plateau

Composed of old crystalline, igneous and metamorphic rocks.

Oldest landamass as it was originally part of Gondwana land.

Has broad and shallow valleys and round hills.

Two divisions, Central Highlands and Deccan Plateau.

Central Highlands

North of the Narmada river.

Covers most of the Malwa plateau.

Vindhyan range on the south.

Aravalis on the northwest.

As you go west you slowly get the desert conditions of Rajasthan.

Sind, Betwal and Ken are some important rivers that drain the region. They do it from southwest to northeast and that is the direction of the slope.

Wider in the west and narrower in the east.

Eastward expansion is locally called Bundelkhand and Baghelkhand. Chotanagpur plateau marks further eastward expansion and it's drained by Damodar river.

Deccan Plateau

Triangular landmass.

Lies to the south of the Narmada river.

Satpura range in the north.

Mahadev, Maikal and Kaimur hills in the east.

Higher in the west and gently slopes towards the east.

Extends towards Meghalaya and North Cachar hills.

Separated by a fault from Chotanagpur plateau.

Some prominent hills are Khasi and Jaintia.

The Ghats

Western Ghats and Eastern Ghats bound the Deccan Plateau. Western Ghats lie parallel to western coast and same thing for Eastern Ghats and eastern coasts.

Western Ghats

0.9km-1.6km elevation.

Cause rain by forcing the rain bearing winds to rise along the slopes.

Height of the Western Ghats increases from north to south.

Highest peaks is Anaimudi (2.695km)

Eastern Ghats.

0.6km elevation.

From Mahanadi valley to Nilgiris.

Discontinuous and irregular, dissected by rivers from Bay of Bengal.

Mahendragiri (1.501km) is the tallest peak.

Udagamandalam or Ooty and Kodaikanal are famous hill stations.

Distinct features of the Deccan Plateau.

Deccan Trap, black soil with volcanic origin. Aravali hills lie on the west and northwest of the plateau.

The Indian Desert

Lies towards the east of the Aravali Hills.

Sandy plain covered with sand dunes.

Rainfall below 150mm per year.

Arid climate and low vegetation.

Streams appear in rainy season and dissapear after the season. They cannot reach the sea.

Luni is the only large river in the region.

Barchans are crescent shaped sand dunes and cover larger areas and longitudinal dunes are prominent as you near Pakistan.

Barchans in Jaisalmer.

The Coastal Plains.

The peninsular plateau is surrounded by coastal strips. These run along the two seas. The western coast is flanked by the Arabian sea. It is made of two parts, Konkan (Mumbaia-Goa), Kannad Plain (Karnataka) and Malabar coast. The eastern coast is flanked by the Bay of Bengal and are much more wide and level. It is made of Northern Circar and Coromandel Coast. Rivers like Krishna, Godavari and Kaveri have made deltas here. One important lake is Lake Chilika.

The Islands

India has two Islands, Lakshadweep and Andaman and Nicobar Islands. Lakshadweep is at the southeast of India and it was earlier known as Amandive, Laccadive and Minicoy. It was changed to Lakshadweep in 1973. Covers 32km^2. Kavaratti island is the administrative group of Lakshadweep. Lots of Flora and Fauna. Pitti island, which is uninhabited has a bird sanctuary. Andaman and Nicobar Islands are to the southeast of India. Bigger and more numerous. Andaman in the north and Nicobar in the south. They may be elevated submarine mountains. Strategic importance to the country. Lots of flora, fauna and forest cover.

Things that we get from different physiographic features.

Mountains: Water and forest wealth.