The Peninsular Plateau:
The Deccan plateau is the oldest structure of India. It is the core of the geology of India. It is surrounded by oceans on three sides. Therefore it is often called Peninsular plateau. It covers an area of 16 lakh sq. km. The average altitude of the plateau varies from 600 to 900 metres. Its limits are formed by the Aravallis in the North Rajmahal Hills and Shillong plateau in the East. There is Malda gap between Rajmahal hills and Shillong plateau. The southernmost point is known as Kanyakumari. It is an ancient, stable, hard block formed by igneous and metamorphic rocks. It was part of Gondwana land.
Division of Peninsular Plateau. A series of low hills, known as Satpura ranges between 21° N to 24° N latitudes divided the Peninsular plateau into two parts.
(a) Malwa Plateau
(b) Deccan Plateau.
(a) Malwa Plateau: The Malwa plateau covers a large part of central highlands. It extends from Aravallis in the West, Ganges valley in the North and East, and Vindhyas in the South. The Aravallis are residual mountains or Relict Mountains. Its highest peaks are Mt. Abu (1158 metres) and Guru Shikhar (1722 metres). This plateau includes Bundelkhand, Baghelkhand and Chambal valley. This Vindhyan plateau consists of long narrow ridges made up of Quartzite rocks. It extends upto Mahadeo Hills, Kaimur range, Maikal range, Rajmahal hills in the East. In the East lies Chotta Nagpur plateau drained by Damodar river. This plateau is the storehouse of minerals of India.
Vindhyas: This range extends from east to west in the north of River Narmada. It separates Northern India from Southern India. Its average height is 300 metres. It starts from Gujarat in the west and goes up to Bihar in the East passing through the Madhya Pradesh.
Satpuras: This mountain range spreads between the Narmada and the Tapti rivers. They extend from Gujarat in the west to Amarkantak in the east. Dhupgarh (1350 metres) is the highest point of these ranges.
(b) Deccan Plateau: This plateau lies South of Narmada river. It is surrounded by mountain ranges on three sides Western Ghats, Eastern Ghats and Satpuras. Narmada and Tapti valleys are rift valleys between Satpuras and Vindhyas. Karnataka Plateau lies between Eastern Ghats and Western Ghats. Deccan plateau is a tilted plateau with a general eastward slope. It covers an area of about 70 lakh sq. km. Its average height varies between 500 metres to 1000 metres.
The rivers have divided this plateau into many sub divisions. N.W. Deccan plateau is made up of lava and is known as Deccan trap.
1. The Western Ghats: The Western Ghats extend from Tapti Valley up to Kanyakumari for about 1500 kms. It has three passes Thai ghat, Bhor ghat and Pal ghat. These ranges rise abruptly from the coast. Short swift streams flow towards the west and do not form deltas. The average height is about 1200 metres. Godavari, Krishna and Cauvery rivers rise from Western ghats and flow towards East. Anai Mudi (2698 metres) is the highest peak.
East-West Cross Profile of the South Indian Plateau
2. Eastern Ghats: Eastern Ghats extend for about 800 kms from Mahanadi valleys upto Nilgiris. These are not continuous ranges. Rivers form wide gaps. Javadi, Shevroy and Nallamalai bills are found in the Southern part.
Nilgiris: The western and eastern Ghats join each other in the south where they are known as the Nilgiris. Doda Beta (2637 metres) is the highest peak in the Nilgiris.
