Geochemical Characteristics and the Sedimentary Environment of Lower Cambrian Argillaceous Rocks on the Kongquehe Slope, Tarim Basin, China

The deposition of the Lower Cambrian argillaceous rocks on Kongquehe slope provides a good opportunity to reconstruct paleoenvironmental conditions Tarim Basin. To explore paleoredox conditions, paleoclimate, and provenance this deposit, 21 samples were collected from Well A, concentrations major trace elements analyzed. V/(V + Ni), V/Cr, Ni/Co, U/Th, Uau, V/Sc ratios indicated that sediments in water body reducing environment, degree reduction weakened bottom top. Sr/Cu, Mg/Ca, Fe/Mn revealed was mainly characterized by warm humid there may be paleoclimatic transition toward drought as recorded Xidashan Formation. chemical alteration index, compositional variation plagioclase index values, Th/U K/Rb mudstone all reflected parent rock study area subject low- medium-degree weathering. Longitudinally, gradually increased then Xishanbulake Formation rare earth well Th–Sc–Zr/10, Th–Co–Zr/10, ∑REE–La/Yb diagrams showed mudstones Formations have common type, sedimentary rich felsic minerals. Additionally, structural setting discrimination SiO2–K2O/Na2O, La–Th–Sc is continental island arc environment has characteristics an active margin.