Geochemical and 13C trends in sedimentary deposits of coastal Pondicherry region, East coast of India – insights from a borehole study

Abstract Major, trace, rare earth elements and 13C isotope results of sediments collected up to the depth of 150 meter below ground level (m bgl) have been interpreted in relation to the provenance, weathering and deposition conditions of a multi layered sedimentary formation of Pondicherry region located in East Coast of India. The samples fall in the coarse to medium grain size range (mean Mz: 0.29 – 1.32) and the sorting values (mean SD: 0.29 – 1.04) mostly infer very well sorted nature of sediments. Skewness (mean Ski: 0.09-0.99) shows the domination of very fine skew while the kurtosis (mean KG: 0.76-7.73) shows sediments from extremely lepto kurtic to platy kurtic nature. Micro-structural studies infer that sediments are derived from multiple sources and transported towards the littoral zone through the fluvial processes. Relatively depleted elemental concentrations with respect to upper continental crust (UCC) (elemental ratios