Geochemical characteristics and geological significance of Early Cambrian argillaceous rocks in Kuruk Tag, Xinjiang

Systematic analysis of petrology and geochemistry of Xishanbulake Formation argillaceous rocks in Tseganbrark was made in this study. The purpose of this paper is to discuss sediment provenance, weathering and tectonic setting of sedimentation basin. The ratios of Al₂O₃/TiO₂, Th/Sc, (Gd/Yb)_N, (Eu/Eu^*)_N, ICV, CIA of argillaceous rocks in Qieganbulakedaban are 24, 0.9, 1.1, 0.6, 1.2, 70 respectively, while these ratios in Moheershan are 10.5, 0.2, 3.5, 1.01, 2.8, 75 respectively. These characteristics indicate that all of argillaceous rocks tended to occur in first-cycle deposit. The source rock of argillaceous rocks in Qieganbulakedaban were granitoids formed in a stable intracontinental environment, whereas the source rock of them in Moheershan were basicintermediate magmatic rocks formed in a volcanic uplift environment. Under the tectonic setting of Rodinia Supercontinent cracking, the cracking of Moheershan was stronger than Qieganbulakedaban. The CIA in the study area demonstrates that the source region of argillaceous rocks suffered from medium degree chemical weathering which reflects a warm and moist climate located in 30°S. The CIA characteristics of vanadium-bearing carbonaceous shales and phosphorite suggest that the sources of vanadium and phosphorus were connected with basic-intermediate magmatism in Sinian and Cambrian.