Deccan Plateau

(from Sanskrit dakshin, or south), a plateau covering the interior of the Hindustan peninsula, between the Narmada River on the north and the Cauvery River on the south. The plateau covers about 1 million sq km. Its surface is raised at the edges and tilted eastward, so that most rivers cross the plateau from west to east and empty into the Bay of Bengal. The plateau’s relief is determined by broad expanses of Mesozoic and Paleo-Neocene outcrops reaching respectively 1,000-1,500, 600-900, and 300-500 m. There are also laterite crusts reaching as high as 100 m, above which rise insular mountains of 1,000-2,000 m with domed peaks. The northwestern part of the Deccan plateau is typified by stepped plateau denudational structures in the relief. The river valleys in the central regions are broad, and those on the borders of the plateau are narrow and precipitous. Geologically, the Deccan plateau forms part of the Indian platform, which is composed chiefly of Archean and Proterozoic gneisses, crystalline schists and quartzites, partially alternating with granite intrusions. In the northwest there are basalt mantles (traps) of the upper Cretaceous and Eocene epochs, ranging in thickness from 1,500 to 1,800 m and covering about 520,000 sq km. There are deposits of iron, copper, manganese, tungsten, gold, and coal.

The climate of the Deccan plateau is subequatorial monsoon. The basic seasons are a dry, cool period (November to February), a hot, dry period (March and April), and a hot, rainy period (May to October). Annual precipitation in the central region is 500-700 mm and on the windward slopes 2,500-3,000 mm. The maximum rain falls in the summer. The average temperature in May, the warmest month, is 29°-32°C, and in January is 21°-24°C. The rivers Narmada, Mahānadī, Godāvari, Cauvery, and the others have a monsoon profile. The predominant soil types are red laterites, reddish-brown soils, and on traps, black tropical soils, or regurs. Zonal types of landscape are monsoon deciduous forests on the windward slopes, dry savanna and sparse forests in the central region, and arid savannas in the west, in the rain shadow of the western Ghats. Virgin forests are preserved on 10-15 percent of the territory, mainly on mountain slopes and hills. They are mainly teak, sal, ironwood, and bamboo. About 60 percent of the territory is cultivated. There are more than 150,000 reservoirs for irrigation and water supply. The basic agricultural crops are grains, beans, oil-bearing plants, and cotton. The remaining territory is a heavily used grazing area, which includes the secondary thin forest, scrub growth, and jungles.