Geochemical (ree and trace elements) characteristics and tectonic setting discrimination of permo-carboniferous sandstone from sikkim lesser himalaya, ne india

Abstract

The geochemical (REE & traces elements) characteristics of Permo-Carboniferous sandstone has been taken into account to decipher tectonic setting and provenance of the Rangit Pebble Slate Formation of Sikkim Lesser Himalaya. The chondrite normalized REE pattern with Eu negative anomaly and a bivariate plot (Th/Co-La/Sc) clearly indicates that studied sediments were likely derived from upper crust felsic source. The average elemental ratio of traces elements La/Sc (3.85), Th/Sc (2.57), Cr/Th (6.64), Th/Co (2.52), La/Co (3.74), and Eu/Eu∗(0.32) also shows close affinities with Upper Continental Crust. The trivariate plot (La-Th-Sc plot, Th-Sc-Zr/10 plot, & Th-Co-Zr/10 plot) and a bivariate plot (Ti/Zr-La/Sc) plotted on the field of passive tectonic region for the Rangit Pebble Slate Formation sandstone. A binary plot between the ratio of Th/Sc-Zr/Sc and Th/U-Th reflects the enrichment of zircon and weathering trend during sedimentary recycling.