<p>Since Mesozoic, the western subduction of Pacific and Philippine Sea plate beneath the Eurasian plates caused significant and complex tectonic deformation of Lower Yangtze Craton and its surroundings. However, the deformation patterns and geodynamic evolution of Lower Yangtze Craton and its surrounding areas remain enigmatic. In this work, we used P wave receiver functions with temporary and permanent seismic stations to detect the crustal structures and anisotropy in this region. Crustal thinning and high Vp/Vs ratios are detected in the Middle-Lower Yangtze metallogenic belt, which may be caused by the upwelling of upper mantle and intrusion of mantle-derived basaltic magma into the lower crust. The fast direction of crustal anisotropy in Hefei basin exhibits nearly east–west direction, which may be caused by the extension and thinning effect of underlying asthenospheric convection and flow. There is decoupled deformation patterns in crust and upper mantle beneath Lower Yangtze Craton and eastern Cathaysia Block, which may reflect relics of tectonic deformation patterns during geological evolution.</p>

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Crustal Structure and Anisotropy in Lower Yangtze Craton and its Implications for Geodynamic Evolution

  • Shanshan Wu,
  • Zigen Wei,
  • Fang Liu,
  • Yuqin Wu,
  • Qinping Gu,
  • Fei Liu,
  • Sichao Jia

摘要

Since Mesozoic, the western subduction of Pacific and Philippine Sea plate beneath the Eurasian plates caused significant and complex tectonic deformation of Lower Yangtze Craton and its surroundings. However, the deformation patterns and geodynamic evolution of Lower Yangtze Craton and its surrounding areas remain enigmatic. In this work, we used P wave receiver functions with temporary and permanent seismic stations to detect the crustal structures and anisotropy in this region. Crustal thinning and high Vp/Vs ratios are detected in the Middle-Lower Yangtze metallogenic belt, which may be caused by the upwelling of upper mantle and intrusion of mantle-derived basaltic magma into the lower crust. The fast direction of crustal anisotropy in Hefei basin exhibits nearly east–west direction, which may be caused by the extension and thinning effect of underlying asthenospheric convection and flow. There is decoupled deformation patterns in crust and upper mantle beneath Lower Yangtze Craton and eastern Cathaysia Block, which may reflect relics of tectonic deformation patterns during geological evolution.