The western margin of the Yangtze Craton was an extensional setting in the Early Triassic and a foreland basin in the Late Triassic.The well-preserved Triassic sediments on the western margin of the Yangtze Craton are ideal targets for studying the sedimentary provenance response to tectonic transformation.Methods:Based on the geological work,the heavy mineral electron probe microanalysis and detrital zircon U-Pb dating were carried out on the Triassic sandstones in this paper.Results:The results of tourmaline electron probe microanalysis show that the Lower Triassic sediments are mainly derived from the granitoids and their associated pegmatites and aplites,metapelites and metapsammites,calc-silicate rocks,and quartz—tourmaline rocks,while the Upper Triassic sediments are mainly derived from the granitoids and their associated pegmatites and aplites,Ca-poor metapelites and metapsammites,and quartz—tourmaline rocks.The proportion of metapelites and metapsammites gradually increases from Lower Triassic to Upper Triassic.Spinel results show that the Lower Triassic sandstones are mainly from large igneous provinces,oceanic island basalts and island arc basalts,while the Upper Triassic sediments are mainly derived from island arc basalts. Detrital zircon U-Pb dating results show that the Early Triassic detrital zircon peak is 251~265 Ma,460~535 Ma,and 544~987 Ma while the Late Triassic detrital zircon peaks are 228~251 Ma,255~387 Ma,429~523 Ma,573~954 Ma,1720~2004 Ma and 2453~2494 Ma.Conclusions: Comprehensive analysis show that the sediments of the Lower Triassic were mainly from Emeishan basalt,Kangdian Oldland and secondary from South Qinling orogenic belt.However,source areas of the Upper Triassic are mainly Emeishan basalt,Kangdian Oldland,Qinling orogenic belt,and North China plate.The differences of provenance in Triassic are mainly related to the collision between the Qinling orogenic belt and the Yangtze plate in the Late Triassic.