Detrital composition characteristics of the Middle Jurassic Shaximiao Formation and constraints on provenance in the middle of Western Sichuan depression

In order to explore its source area and properties of source in the Middle Jurassic Shaximiao Formation of the middle of Western Sichuan depression, clastic rock debris composition features and the projection point of Dickinson triangle were applied to discuss deeply the source area and the attributes of source area in the study area. The results show that Zhongjiang,Xindu and other areas in the northeast are characterized by low quartz content and high feldspar content, belong to tectonic background of cut island arc, basement uplift, transitional continent. But Yazihe, Xiaoquan and other areas in the west of the study area are characterized by high quartz content and low feldspar content, having relatively high metamorphic detrital content, belong to the tectonic setting of recycling orogeny. Combined with the evoluation characteristics of the periperial orogenetic belt during deposition of Shaximiao Formation, it is considered that Micang mountain and Daba mountain were the major provenance areas of Zhongjiang,Xindu and other areas in the north of the study area, while Longmenshang was the major provenance area of Yazihe, Xiaoquan and other areas in the west of the study area.