Major and trace element geochemistry of lake sediments, India: implications for weathering and climate control

Abstract

Climate plays an essential role in weathering of rocks, and a rich record of climatic change is preserved in rocks and sediments. The physical and chemical weathering also largely depend on climate prevailing in the area, apart from other factors. In an attempt to understand the dominance of physical over chemical weathering processes, the textural and geochemical studies of Wular Lake sediments from Jammu and Kashmir, northern India, have been taken up in the present study. These sediments documented several attention-grabbing processes that operated during weathering, transportation, and deposition. Investigations have revealed that physical weathering dominated over chemical weathering, resulting in enhanced rates of erosion and consequent deposition of large detritus into the lake. Lake sediments and source rock chemistry are comparable, indicating low to moderate chemical weathering history of the source region which is consistent with cold regions and steep slope areas. Unusual enrichment of Cr values in sediments compared with source rocks signify a process of sediment–water interaction where Cr is removed from water and preferentially adsorbed onto clay fraction of sediments.