Provenance of the Lower Triassic Clastic Rocks in the Southwestern Margin of the South China Craton and Its Implications for the Subduction Polarity of the Paleo-Tethyan Ocean

The southwestern margin of the South China Craton preserves a Late Permian to Early Triassic sedimentary succession, provenance which helps constrain magmatic history and tectonic evolution Paleo-Tethyan Orogen. In this study, we present new detrital zircon U-Pb age, trace element, Hf isotope whole-rock geochemical composition analyses from Lower Qingtianbao Formation, distinguish clastic rocks. results show that zircons Formation are characterized by an age spectrum unimodal, with peak ∼260 Ma, have affinity within-plate sources. Most these positive ε (t) values (+1.6 +5.9), similar those Emeishan rhyolites. geochemistry most samples shows no Nb–Ta anomalies on primitive mantle-normalized elemental diagrams. These features imply source related volcanic Integration geologic records in Craton, suggest Ocean may undergo unidirectional subduction westward beneath Indochina Block during Permian–Early Triassic.