Geochemistry Of Terrace Deposits Of Upper Alaknanda Basin
Geochemical and clay mineralogical study of terrace deposits in the higher altitude will provide the information of nature and extent of chemical weathering in the upper reaches of the river basin. In this study sediment samples from terrace deposits of Badrinath valley, upper Alaknanda basin were collected for clay mineral identification and quantification, and geochemical analysis to understand chemical weathering intensity prevailing during sediment deposits. The deposits are interlayered with the pebble and the boulder layers which are due to the changing energy condition caused by climatic variations. Bulk and clay mineralogy, grain size distribution of <38 micron size suggest that physical weathering is dominated in the study are compare to chemical weathering. Presences of illite in specific site indicate a colder climatic condition (i.e. glacial period) during development of terraces. CIA, A-CN-K, A-CNK-FM ternary diagram suggest low intensity of chemical weathering in the upper catchment area and grain size reduction is mainly due to physical weathering. Bulk geochemistry is indicating felsic source rock.