Abstract:

Based on sedimentary structure and sampling of the Middle-Upper Ordovician in Queerqueke, Yuanbaoshan and Nanyaerdang profiles in Quruqtagh area, the provenance and tectonic setting of the MiddleUpper Ordovician are studied, combined with the well and seismic data. The Queerquek Formation in the MiddleUpper Ordovician is thought to be the flysch deposition. According to the sedimentary structure, heavy mineral assemblage, mineralogical maturity, cathode luminescence and characteristics of major elements, trace elements and rare earth elements, the tectonic setting of the MiddleUpper Ordovician is the continental island arc and active continental margin. In the early sedimentary stage, the provenance of Queerquek Formation came from the north paleoland mass, which was composed of granitoid and metamorphic rocks; in the middlelate sedimentary stage, some pyroclastic from the Altyn orogenic belt turned to be a new provenance. The analysis of the provenance of the MiddleUpper Ordovician provides a basis for studying the relationship between the tectonic uplift and the sedimentary filling, and for predicting the distribution of tight sandstone of the Middle-Late Ordovician.

Key words: tectonic setting, sedimentary source, Middle-Upper Ordovician, Tarim Basin