Geochemistry of surface sediments in parts of Bandipora–Ganderbal areas, Kashmir valley, western Himalaya: Implications for provenance and weathering

Sediment geochemistry is an important tool to understand the sediment provenance and weathering. The present study describes the geochemical distribution, the provenance and the degree of weathering in surface sediments in parts of Bandipora–Ganderbal areas, Kashmir valley, western Himalaya. Following the standard operating procedure of the Geological Survey of India, high-density sediment sampling over an area of 800 km2 of toposheet Nos. 43J/11 and 43J/12 (part) was carried during the Field Season Programme of 2014–2015. A total of 200 stream and slope wash sediment samples collected on a 2 × 2 grid pattern, covering an area of 800 km2 and 10 numbers of duplicate samples were used in this study. An analysis of major and trace element concentrations of the sediment samples revealed significant changes corresponding to different geological formations of the area. The correlation matrix of SiO2, Al2O3, TiO2, Fe2O3, MnO, K2O, Th and Y showed a positive correlation with each other and negative correlation with CaO, MgO and Sr, thereby indicating two dominant geological provenances of the sediments. Two dominant geochemical patterns revealed provenances from basaltic and carbonate rock formations in the area. Furthermore, an analysis of geochemical weathering indices (chemical index of alteration and chemical index of weathering) revealed a poor (27) to moderate (78) degree of weathering in this area. This observation is further substantiated by the immaturity of the soil sediments in the area.