The Himalayan Foreland Basin
The Indus-Ganga-Brahmaputra Plains are important regions that are characterized by a flexural asymmetrical basin, which is bounded by the rising Himalaya mountain range in the north and a subdued fore bulge in the south. The axial river of the basin is the Ganga, which is joined by major Himalayan tributaries before draining into the Bay of Bengal. The mighty Brahmaputra river also meets the Ganges and forms a major deltaic depocenter in the Bengal basin. The Indus borders it to west. The exposed stratigraphy of the basin exhibits an interplay Himalayan tectonics, climate, sea level changes and sediment supply and faunal evolution over the past 125,000 years. This interplay has created a complex and dynamic geological landscape that is rich in natural resources and biodiversity.
The Brahmputra basin is one of the most ecologically diverse regions of the Indian foreland basin, containing significant portions of the Himalayan and Indo-Burmese biodiversity hotspots. The region is known for its unique combination of tropical evergreen and deciduous forests, mixed deciduous forest, riverine grasslands, bamboo orchards, and numerous wetland ecosystems that support a wide variety of plant and animal species. The Indus-Ganga-Saraswati basins and Brahmaputra Plains are also important agricultural regions and provide livelihoods to millions of people. The fertile alluvial soils of the region have supported agriculture for thousands of years, and the rivers have been used for transportation, irrigation, and fishing.
In addition to its ecological diversity, the Himalayan foreland basin is also home to a fifth of present-day humanity and is characterized by diverse human cultures. Recent archaeological research from the region is challenging the concepts about the origin and divergence of human populations from the continent of Africa. India is considered one of the nuclear areas of early plant domestication, and the observed human diversity on the sub-continent is attributed to amicable and adequate shelters with conducive climatic and environmental conditions that offered life to a variety of human populations from the Late Pleistocene to today's environment. The existence of modern humans in India has been reported since the Early Upper Paleolithic, followed by several waves of human migration into the subcontinent, which gave rise to various ethnic groups of South Asia comprising tribes, castes, and populations identifying themselves by different religions, being largely endogamous and hence revealing complex, multilayer genetic differentiation.