The polarity and subduction processes of the Paleo-Tethys Ocean on the Tibetan Plateau represent a key scientific issue for deciphering the tectonic evolution of the Tethyan realm.However,the sedimentary response mech...The polarity and subduction processes of the Paleo-Tethys Ocean on the Tibetan Plateau represent a key scientific issue for deciphering the tectonic evolution of the Tethyan realm.However,the sedimentary response mechanisms at its continental margins still lack systematic investigation.This study focuses on the Lower Triassic Yingshuiquan Formation at the southern margin of the North Qiangtang terrane,integrating petrological analysis,sedimentary facies analysis,detrital zircon U-Pb geochronology,and trace element geochemistry.Results indicate that the maximum depositional age of the Yingshuiquan Formation is Early Triassic.Its detrital zircons yield a dominant age population of 354–247 Ma and subordinate populations of 378–484,550–695,837–925,1712–1951,and 2389–2695 Ma.The formation was deposited in a carbonate platform environment dominated by oolitic shoal subfacies.Provenance analysis reveals that the >378 Ma detrital zircon components were primarily derived from recycled materials within the accretionary wedge complex of the subduction zone and the North Qiangtang terrane,while the syndepositional zircons(354–247 Ma) were mainly supplied by the continental margin magmatic arc within the North Qiangtang terrane.Synthesizing these new data with previous studies on the subduction and demise of the Longmu Co-Shuanghu Paleo-Tethys Ocean(LSPTO),we propose that during the Early Triassic,the LSPTO was undergoing northward subduction and consumption.An oceanic basin,evolving into a forearc basin,persisted between the accretionary wedge and the magmatic arc.The Yingshuiquan Formation represents the sedimentary record of this forearc basin.展开更多
基金supported by the National Science and Technology Major Project(Grant No.2024ZD1001104)the National Natural Science Foundation of China(Grant No.42172226)the Fundamental Research Funds for the Central Universities(Grant No.2025-JCXK-21)。
文摘The polarity and subduction processes of the Paleo-Tethys Ocean on the Tibetan Plateau represent a key scientific issue for deciphering the tectonic evolution of the Tethyan realm.However,the sedimentary response mechanisms at its continental margins still lack systematic investigation.This study focuses on the Lower Triassic Yingshuiquan Formation at the southern margin of the North Qiangtang terrane,integrating petrological analysis,sedimentary facies analysis,detrital zircon U-Pb geochronology,and trace element geochemistry.Results indicate that the maximum depositional age of the Yingshuiquan Formation is Early Triassic.Its detrital zircons yield a dominant age population of 354–247 Ma and subordinate populations of 378–484,550–695,837–925,1712–1951,and 2389–2695 Ma.The formation was deposited in a carbonate platform environment dominated by oolitic shoal subfacies.Provenance analysis reveals that the >378 Ma detrital zircon components were primarily derived from recycled materials within the accretionary wedge complex of the subduction zone and the North Qiangtang terrane,while the syndepositional zircons(354–247 Ma) were mainly supplied by the continental margin magmatic arc within the North Qiangtang terrane.Synthesizing these new data with previous studies on the subduction and demise of the Longmu Co-Shuanghu Paleo-Tethys Ocean(LSPTO),we propose that during the Early Triassic,the LSPTO was undergoing northward subduction and consumption.An oceanic basin,evolving into a forearc basin,persisted between the accretionary wedge and the magmatic arc.The Yingshuiquan Formation represents the sedimentary record of this forearc basin.
