Geochemistry Of Proglacial Lake Deposits Of Upper Alaknanda Basin
Many researchers have recorded climatic upheaval in the Himalaya during the Late Quaternary. The chemical weathering in the Upper Alaknanda basin has changed during the glacial and interglacial period. Different sediment archives such as pro-glacial deposits and terrace deposits act as repository to understand the paleo-weathering intensity of the sediment.In this study geochemistry of sediments of pro-glacial lake deposits found in the Badirinath valley of upper Alaknanda basin was carried out to understand the paleo-climate of the study area by identifying the clay minerals, intensity of chemical weathering and to estimate the distance travelled from the source. The lake deposits are thinly laminated and lack boulder and pebble layers. Sediment deposits at the right bank of Alaknanda River near Bamini village are more likely lake deposits as compare to left bank deposits which is terrace. By clay mineral identification, it is concluded that the paleo-climate of the pro-glacial lake deposits were cold and is deposited during glacial period. XRF analysis in terms of CIA calculation, A-CN-K plot and A-CNK-FM plot suggests that there is low degree of chemical weathering occurred in the study area. The percentage of clay silt fractionation calculation by gravity setting method conforms that the sediment were not travelled far from their source.