Peninsular Plateau

• Roughly triangular in shape with its base coinciding with the southern edge of the great plain of North India. Apex of the triangular plateau is at Kanniyakumari.
• It covers a total area of about 16 lakh sq km (India as a whole is 32 lakh sq km).
• The average height of the plateau is 600-900 m above sea level (varies from region to region).
• Most of the peninsular rivers flow west to east indicating it’s general slope.
• Narmada-Tapti are the exceptions which flow from east to west in a rift (rift is caused by divergent boundary (Go back to Interaction of plates).
• The Peninsular Plateau is a one of the oldest landforms of earth.
• It is a highly stable block composed mostly of the Archaean gneisses and schists {Rock System}.
• It has been a stable shield which has gone through little structural changes since its formation.
• Since few hundred million years, Peninsular block has been a land area and has never been submerged beneath the sea except in a few places.
• Peninsular Plateau is an aggregation of several smaller plateaus, hill ranges interspersed with river basins and valleys.

Chotanagpur Plateau

• Chotanagpur plateau represents the north-eastern projection of the Indian Peninsula.
• Mostly in Jharkhand, northern part of Chhatisgarh and Purulia district of West Bengal.
• The Son river flows in the north-west of the plateau and joins the Ganga.
• The average elevation of the plateau is 700 m above sea level.
• This plateau is composed mainly of Gondwana rocks.
• The plateau is drained by numerous rivers and streams in different directions and presents a radial drainage pattern. {Drainage Pattern}
• Rivers like the Damodar, the Subarnrekaha, the North Koel, the South Koel and the Barkar have developed extensive drainage basins.
• The Damodar river flows through the middle of this region in a rift valley from west to east. Here are found the Gondwana coal fields which provide bulk of coal in India.
• North of the Damodar river is the Hazaribagh plateau with an average elevation of 600 m above mean sea level. This plateau has isolated hills. It looks like a peneplain due to large scale erosion.
• The Ranchi Plateau to the south of the Damodar Valley rises to about 600 m above mean sea level. Most of the surface is rolling where the city of Ranchi (661 m) is located.
• At places it is interruped by monadnocks (an isolated hill or ridge of erosion-resistant rock rising above a peneplain. Ex: Ayers Rock in Australia) and conical hills.
• The Rajmahal Hills forming the north eastern edge of the Chotanagpur Plateau are mostly made of basalt and are covered by lava flows {Basaltic Lava}.
• They run in north-south direction and rise to average elevation of 400 m (highest mount is 567 m). These hills have been dissected into separate plateaus.