Source Tracer and Its Tectonic Significance of the Ordovician-Silurian Clastic Rocks in Southern Nuratau, Uzbekistan

Research on the Early Paleozoic geological bodies exposed in Nuratau, Uzbekistan, is key to reconstruct the tectonic setting and evolution process of the Turkestan Ocean in the western south Tianshan.This paper analyzed the source of sedimentary material and the tectonic attributeby source tracing of the Ordovician-Silurian clastic rocksin southern Nuratau.The results show that this suite of clastic rocks is mainly comprised of fine-grained greywacke which formed inoffshore beach setting of passive continental margin. The lithology is of acidic magmatic rocks and old sedimentary rocks.The peak age of the detrital zircons in fine-grained sandstone is nearly 800Ma,which corresponds to Rodinia supercontinent cracking event;the secondary peak ages are 530Ma and 440Ma, suggesting a large terrane assembly event in the Early Paleozoic. The authors have reached the conclusion that in Early Paleozoic the Turkestan Ocean spread in the east-west direction with the active continental margin to the north and the passive continental margin to the south.Sedimentary materials of the passive continental margin were from the Rodinia supercontinent cracking event and the Early Paleozoic tectonic event.