Collisional orogens form when tectonic forces amalgamte fragments of Earth's continental lithosphere.The sutures between individual fragments,or terranes,are potential sites of weakness that facilitate sub-sequent continental breakup.Therefore,the lithospheric architecture of collisional orogens provides key information for evaluating the long-term evolution of the continental interior:for example,the South China Block(SCB),where the tectonic history is severely obscured by extensive surface deformation,magmatism,and metamorphism.Using new passive-source seismic models,we show a contrasting seis-mic architecture across the SCB,with three prominent crustal dipping structures across the Jiangnan Orogen.Combined with constraints from multi-disciplinary regional geophysical datasets,these pro-nounced dipping patterns are interpreted as relict wedge-like lithospheric deformation zones initiated in the fossil collisions that assembled the Yangtze Block and the SCB.The overall trend of these tectonic wedges implies successive crustal growth along paleo-continental margins and is indicative of northward subduction and docking of accretional terranes.In contrast,no such dipping structures are preserved in the Cathaysia Block,indicating a weak and reorganized lithosphere.The variations in the deformation responses across the SCB reflect the long-term modifications of the lithosphere caused by prolonged col-lision and extension events throughout the tectonic history of the SCB.Our results demonstrate the crit-ical roles that suture zones played in the successive growth and evolution of the continental lithosphere.

Tingzi Li;Mingming Jiang;Liang Zhao;Weihua Yao;Ling Chen;Yang Chu;Baolu Sun;Yinshuang Ai;Bo Wan;Klaus Gessner;Huaiyu Yuan

State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China;Australian Research Council Centre of Excellence for Core to Crust Fluid Systems,Department of Earth and Environmental Sciences,Macquarie University,New South Wales 2109,Australia;Centre for Exploration Targeting,University of Western Australia,Crawley WA 6009,Australia;Key Laboratory of Earth and Plantenry Physics,Chinese Academy of Sciences,Beijing 100029,China;University of Chinese Academy of Sciences,Beijing 100049,China;Guangdong Provincial Key Lab of Geodynamics and Geohazards,School of Earth Sciences and Engineering,Sun Yat-sen University,Guangzhou 510275,China;Geological Survey of Western Australia,Perth WA 6001,Australia

科学通报（英文版）

[1]Tingzi Li;Mingming Jiang;Liang Zhao;Weihua Yao;Ling Chen;Yang Chu;Baolu Sun;Yinshuang Ai;Bo Wan;Klaus Gessner;Huaiyu Yuan-.Wedge tectonics in South China:constraints from new seismic data)[J].科学通报（英文版）,2022(14):1496-1507

amalgamte,accretional,Cathaysia,lision

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