Hindustan Peninsula

a peninsula in South Asia with an area of approximately 2 million sq km. In the west it is washed by the Arabian Sea and in the east by the Bay of Bengal of the Indian Ocean. The northern border is conventionally drawn from the delta of the Indus to the delta of the Ganges. A significant part of India and parts of Pakistan and the People’s Republic of Bangladesh are situated on the Hindustan Peninsula.

The western coast (Konkan and the Malabar Coast) is a narrow, aggradational lowland with bays and rocky capes, and the eastern coast (Coromandel Coast) is an abrasion plain with lagoons and hills formed from granites and gneisses. The Deccan plateau (average altitude of approximately 800 m) occupies a large portion of the Hindustan Peninsula and is characterized by a mesa-berm relief in the northwest and extensive distribution of rolling peneplains on crystalline foundations. Its raised western periphery (the Western Ghats) descends in steep grades toward the ocean. In the east there is a group of block massifs of various origins that together are called the Eastern Ghats. In the south of the Hindustan Peninsula are found the Nilgiri, Palni, Anaima-lai (Mt. Anai Mudi with a height of 2,698 m), and Cardamon hills, which are divided into separate massifs.

The Hindustan Peninsula is part of an ancient Precambrian Indian (Hindustan) platform, which also encompasses the basins of the middle and upper courses of the Indus, Ganges, and Brahmaputra rivers and the island of Sri Lanka (Ceylon). The platform is composed of Archean gneisses, metamorphosed granites, and vulcanites, which in certain areas are covered by a sheet of sedimentary rock.

Powerful sheet eruptions of basalts occurred in the area of the modern Deccan plateau during the end of the Cretaceous and the beginning of the Paleocene. Then there occurred a sinking of the platform’s outer limits along the coasts of the Arabian Sea and Bay of Bengal. Sinkings of preoceanic depressions continued during the Cenozoic. During the Myocene a graben emerged, consisting of a strait separating the Ceylon horst from the remainder of the platform. At the end of the Cenozoic, along the northwestern, northern, and northeastern peripheries of the platform, there emerged the large structures of the Sulaiman Range, the Himalayas, and other mountains, along the uplifts of which a system of frontal troughs was formed.

The interior of the Hindustan Peninsula has abundant supplies of mineral resources. Large deposits of iron and manganese ores, gold, nonferrous metals, graphite, and rare elements are related to metamorphic rocks and granites of the platform foundation. The sedimentary sheet includes deposits of coal and oil. There are diamond and monazite placers.

The climate is subequatorial monsoon. The median temperature in January is 21°C in the north and 29°C in the south. In May, temperatures reach 40°C. Annual total precipitation in the central area of the Hindustan Peninsula is approximately 700 mm, and on the windward slopes up to 3,000 mm. Up to 90 percent of the precipitation falls during the summer monsoons (from May to October). Most of the rivers cross the Hindustan Peninsula from west to east in tectonic valleys, where broad alluvial plains alternate with gorges filled with rapids. Flowing into the Bay of Bengal, rivers frequently form deltas. The rivers of the Arabian Sea basin are usually short and descend abruptly; notable exceptions are the Narmada and Tapti rivers in the north of the Hindustan Peninsula. The rivers are fed by rain. Monsoon conditions with summer and fall high waters prevail. Floods are frequent. The Godavari and Krishna and the lower reaches of the Narmada and Tapti are navigable. The rivers are used extensively for irrigation. Some of the soils are red, and those that are on basalts are black tropical soils (regurs). Natural vegetation consists of damp tropical evergreen forests on the windward slopes of the Western Ghats; monsoon deciduous forests (of teak and sal), savanna forests, and savannas in central areas; and mangrove forests in the deltas. Natural terrains are considerably varied over large areas. Cultivated savannas predominate— groves of palms and fruit trees among the fields. Animal life has been largely destroyed, but Indian elephants, lions, wild bulls, tigers, and panthers have been preserved, as well as many monkeys, reptiles, and birds.