Changes of provenance of Permian and Triassic sedimentary rocks from the Ailaoshan suture zone (SW China) with implications for the closure of the eastern Paleotethys

•The Ailaoshan Permian clastic rocks have likely a weakly-weathered mafic-intermediate detrital source.•The Ailaoshan Upper Triassic clastic rocks have likely a strongly-weathered, relatively felsic detrital source.•The Mid-Triassic clastic rocks have likely a mixed provenance of a volcanic arc and cratonic interior.•The Upper Triassic change in sediment provenance may have resulted from the final closure of Ailaoshan Ocean.