(Study Material) Geography - World & Indian (Physiography of India)

Geography - World & Indian (Physiography of India):

Indian landmass can be divided into the following units:

• Northern mountains or Himalays

• Northern plains

• peninsular plateau

• Western and Eastern coastal plains

• Islands

Survey of the Himalayas

Longitudinally Himalayas can be divedinto the following 5 sections.

a) Kashmir Himalayas: The average height of this section is around 3000m. Pir panjal range and the valley of Kashmir lies in this section

b) Punjab Himayalas characterised by rugged northern slopes and forested southern slope. High peaks are rare, Likes like Manasarovar,Rakas, passes like Zojila, Rohtang,Bara Lapcha and valleys like Kangra,Lahul and spiti lies in this section.

c) Kumaon Himalayas extends from Sutlej to kali river. Pilgrimage centres like Badarinath and gangotri lies in this section

d) Central Himalayas extends from Kali to Tista and the highest peaks in the world including Himalayas situated here.

e) Assam Himalayas extend from Tista to Brahmaputra. Naga and the Patkai bum hills are included in this section forms a watershed between India and Myanmar.

Vertically the himalayan ranges can be classified into the following in the ranges from north to south.

a) Greater/ Outer Himalayas: The average height is 6000 m and the average width is 120 to 190 kms and these ranges are composed of archaen rocks like granite, gneisses and schists. These ranges have highest mountains in the world and several passes.

b) Lesser Himalayas/Himachal ranges has an average height of 3500-5000m and has a width of 50-80 km. These ranges are composed of metamorphic rocks and unfossiliferous metamorphic rocks. This range has the famous and beautiful hill stations which include Shimla, Mussoorie, Nainital, Ranikhet etc. Imporant ranges include Pir Panjal,Dhaula Dar, Nag Tiba.

c) Sub Himalayas or shivaliks ranges have an average height of 1000 to 1500 m. and have an average width of 15 to 50 kms. These ranges are made of clay, sand,gravel ,slate, boulders etc. The doon valleys are situated in the ranges which includes dehradoon, patlidoon, and Kothridon.

Significance of Himalayas

1) They are the source of perennial north Indian rivers
2) bring fertile soils
3) Blocks the cold wind from North and monsoon winds
4) rich variety of flora ,fauna and natural resources like petroleum, uranium, limestone, herbs etc

Survey of the Himalayas

Longitudinally Himalayas can be divedinto the following 5 sections.

a) Kashmir Himalayas: The average height of this section is around 3000m. Pir panjal range and the valley of Kashmir lies in this section

b) Punjab Himayalas characterised by rugged northern slopes and forested southern slope. High peaks are rare, Likes like Manasarovar,Rakas, passes like Zojila, Rohtang,Bara Lapcha and valleys like Kangra,Lahul and spiti lies in this section.
c) Kumaon Himalayas extends from Sutlej to kali river. Pilgrimage centres like Badarinath and gangotri lies in this section
d) Central Himalayas extends from Kali to Tista and the highest peaks in the world including Himalayas situated here.
e) Assam Himalayas extend from Tista to Brahmaputra. Naga and the Patkai bum hills are included in this section forms a watershed between India and Myanmar.

1. Northern Mountains

These mountain systems are one of the youngest of Fold Mountains in the world, characterised by its youthfulness, tectonic origin, great erosive capacity. Northern mountain consists of Himalayan ranges and trans himalaya which lies north of the great Himalayas. Karakoram , ladak and zaskar ranges are the part of trans Himalayas. Mt. K2 (Godwin Austin) the highest mountain in India is situated on the karakoram range. These ranges converge on the Palmir plateau.

2. Northern Plains

It is formed by the sediments brought by rivers from the Northern and southern side covers an area of 7.5 lakhs sq. km and extends from Punjab to Assam.

Bhabar: These are porous and gravel ridden plain at the foothills of Himalaya. Streams disappear in this area except in the monsoon season

Terai: The streams reappear in this area and are poorly drainded and forested
Bhangar: The term used to refer older alluvium in the river beds Khader: It refers to the new alluvium in river beds in low lying zones.

North Indian plains have highly fertile soils, perennial water source and a good clime suited for agriculture. Although the North Indian plains cover 30% of the geographical area of India, it supports 40% of its population.

3. Peninsular plateau

It is the oldest part of India known as the Indian Plate. This division covers whole of the peninsula in the form of an irregular triangle. The peninsular plateau can be sub divided into the following

a) Aravallis are relict mountains lie to the north west of the peninsula. These are highly eroded and deeply worn down. Mt. Abu is an important peak of Aravallis.
b) Bundelkhand lies in the east of Aravallis, formed by the erosion of gneisses and quartizites which offers the natural sites for water storage.
c) Malwa is drained by chambal and betwa
d) Vindhyan Kaimur range is a escarpment between Narmada and son valleys.
e) Chhotanagpur plateau is the mineral rich area in India in the east of the son river
f) Shillong Plateau is the continuation of the Deccan Plateau
g) Deccan plateau is an elevated tableland consisting of horizontal lava beds and has a homogeneous sloping towards east and south east.
h) Karnataka Plateau composed of gneisses and schists and the two main sub divisions are Malnad and Maidan.
i) Western Ghats: It is also known as sahyadris stretch continuously to the southern tip have a general altitude 900-1100 kms. Dodabetta (2637m) is the highest peak inthe Nillagiri range. Anaimudi (2695 m) in annamalai is the highest peak in South India.
j) Eastern Ghats are broken hills with no well defined structure. The eatern ghat are called northern hills in the northern sector , cudappah ranges in the middle sector and Tamil nadu hills in the southern sector.

4. Coastal Plains:

This is the region between the coast and mountain ranges of the peninsular plateau. This can be divided into western and eastern coast. With the exception of Gujarat, the western coast is narrower than the eastern coast. It has characteristic lagoons or backwaters called kayals such as Asthamudi and vemband in the southern most stretch. The eastern coast has developed deltas of major rivers following through it.

5. The islands:

India has 247 islands of which 204 lie in the Bay of Bengal and the remaining in the Arabian sea and gulf of mannar. The Andamans and the Nicobars form two major groups in Bay of Bengal Group. These 2 major groups are separated by Ten degree channel which 121 km wide. This chain of islands are formed by the submergence of Arakan Yoma ranges . The Barren and Narcondam islands , situated north of Port Blair , are volcanic islands. Lakshadweep islands are a group 27 of coral origin and are surrounded by fringing reefs with a total area of only 32 square kilometers. The pamban island , situated between India and Sri Lanka , has a rocky surface, is an extension of the peninisular surface in Ramnad district of Tamil Nadu.