Sediment Composition of the Thakuran River Basin of the Sunderbans

Abstract

Thakuran River sediments are typical estuarine. Lithogenic constituents are dominant with about 85-90% in bulk and biogenic components constitute the rest (10-15%). Quartz, feldspars, mica, lithic fragments and some heavy minerals are the main terrigenous constituents. Secondary overgrowth of quartz with multiple rims of inclusions suggests their derivation from sedimentary rocks of different cycles of sedimentation. The heavy mineral assemblage in the sediments lead to conclude that the sediments have been derived from the acid igneous rocks of the Himalayas in the north and the metamorphic rocks of the Precambrian shields of the west and north-west of Bengal Basin. Benthic foraminiferal assemblage indicates a shallow water, moderate to low salinity environment of deposition.