Geochemical and Radionuclide studies of sediments as tracers for enrichment of beach and alluvial placers along the eastern coast of India

Abstract

The deltaic environment of the river basin and the beach associated with the meandering nature of river are considered for the exploration of REEs and Radionuclides. A multi-element based geochemical survey of stream and beach placers was carried out along the eastern coast of India to emphasizes the role of stream and river tributaries in the transportation and deposition of heavy mineral placers. The lithology of the river basin, the nature and number of channels, the meandering nature, delta and slope of the river influences the distribution of heavy minerals as placer deposits. The morphology of river basin along with the elevation profile plays a significant role towards the enrichment of heavy minerals. It was observed that the total Rare Earth Element (REE) content was ∼5.2 and ∼23.83 times higher than the UCC values for the Rushikulya River and Mahanadi River sediments, respectively. The total REEs were ∼90 times higher in the Podampata beach sediments and ∼20 times higher in the Paradeep beach sediments compared to UCC respectively, and exhibit a negative Eu anomaly. Th/U ratio is higher in beach sediments than the river sediments as compared to the UCC, which indicates the presence of radioactive heavy minerals in the former. The concentration of radionuclides as well as REE’s, exhibit specific enrichment for the beach sediments, at particular locations.