Figure 14 – Peninsular India: Relief

3.3.1. The Deccan Plateau

This physiographic division is the largest region (about 7 lakh square km) of the Great Indian Plateau. The shape of this plateau is triangular and lies to the south of the river Narmada. 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.The Satpura range is formed by a series of scarped plateaus on the south, generally at an elevation varying between 600-900 m. It is a classic example of the relict mountains which are highly denuded and form discontinuous ranges. The Deccan Plateau is higher in the west and slopes gently eastwards.

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. These are block mountains formed due to the downwarping of a part into the Arabian Sea. Western ghats lie parallel to the western coast from mouth of Tapi rover to Kanyakumari. The western slope is steeper as compared to gentle eastern slope. Thal, Bhor and pal Ghats are major passes of Western Ghats. The Eastern Ghats stretch from the Mahanadi Valley to the Nigiris in the south. The Eastern Ghats are discontinuous and irregular and dissected by rivers such as Mahanadi, the Godavari, the Krishna, the Kaveri draining into the Bay of Bengal. Shevroy Hills and the Javadi Hills are located to the southeast of the Eastern Ghats.

Western Ghats are comparatively higher (900-1600m) in elevation and more continuous than the Eastern Ghats (600m). 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. Mahendragiri (1,501 metres) is the highest peak in the Eastern Ghats. The Eastern and the Western Ghats meet each other at the Nilgiri hills.

3.3.2. The Central Highlands

It extends between Vindhayalchal range in South and Great Northern Plains in nroth. The Aravallis form the west-northwestern edge of the Central Highlands. An eastern extension of the Central Highland is formed by the Rajmahal hills. Malwa plateau forms the dominant part of the Central Highlands. The part of the Central Highlands which extends to the east of Malwa Plateau is known as Bundelkhand and is further followed by Baghelkhand and the well known Chhotanagpur Plateau with large mineral reserves. Chhotanagpur is drained by Damodar river. The Mahadeo Hills, Kaimur Hills and Maikal Range lie towards further east. The valley of Narmada has been formed due to the subsidence of the land mass between the Vindhyas and the Satpuras.

The general elevation of the Central Highlands ranges between 700-1,000 m and it slopes towards the north and northeastern directions. Most of the tributaries (Chambal, Sind, Betwa, Ken) of the river Yamuna have their origin in the Vindhyan and Kaimur ranges. Banas, tributary of the river Chambal, originates from the Aravalli in the west.

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. Aravallis hills extend from Gujarat, through Rajasthan to Delhi in the northeasterly direction for a distance of about 700 km till Delhi. The highest peak of the Aravalli hills is Gurushikhar (1722 m) near Mt. Abu, hill station.