e="MARGIN: 0cm 0cm 0pt">e="FONT-FAMILY: ’Times New Roman’,’serif’">Based on an analysis of characteristics of sandstone and clastic components as well as the regional tectonic setting, the authors also investigated the direction of the sources. The results show that there exist multi-provenances of upper Triassic Xujiahe Formation in the middle part of west Sichuan depression, as evidenced by the Dickinson discriminating diagrams of modal composition. Mineral assemblages and cathodoluminescence colors of quartz suggest that the mother rock of xu-2 and xu-3 period was acidic rock and that of xu-4 period is sedimentary rock in Dayi, the mother rock of Xujiahe period is mainly composed of sedimentary rock and metamorphic rock.espace prefix = "o" ns = "urn:schemas-microsoft-com:office:office" />