Quaternary sediments of Indo-Gangetic, Brahmaputra and adjoining inland basins and the problem of demarcation of Pleistocene-Holocene Boundary
Keywords:Palaeoenvironment, Indo-Gangetic Basin, Brahmaputra Basin, Himalayan Orogenic Movement, Quaternary (India)
The Quaternary sediments deposited in the Indo-Gangetic, Brahmaputra and adjoining smaller inland basins and Duns formed after the Middle Pleistocene Himalayan Orogenic Movement (HOM-4), are fluvial-fluviolacustrine and or lacustrine in nature. A synthesis of the available data in the Brahmaputra Basin and its comparison with that of the Indo-Gangetic Basin and Duns suggests two cycles of sedimentation, separated by a period of erosion and non-deposition and continuous in inland basins, such as Bhimtal-Naukuchia Tal, Hawalbagh in Kumaun region in Uttar Pradesh and Loktak Lake in Manipur. The sediments of the first cycle which terminated in late Upper Pleistocene are, in general, oxidised and referred to as the Older Alluvium, while that of the second assigned to Holocene, is unoxidised grey in color and constitutes the Newer Alluvium.