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Formation and exhumation of ultra-high pressure rocks through delamination and mantle upwelling: Evidence from seismic tomographic data beneath the Qinling-Dabie Orogen, Central China
  • Chuansong He,
  • Huili Guo,
  • M Santosh
Chuansong He
Institute of Geophysics China Earthquake Adminstration

Corresponding Author:[email protected]

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Huili Guo
Institute of Geophysics, China Earthquake Administration
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M Santosh
Ocean University of China
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Abstract

The Qinling-Dabie Orogenic Belt (QDOB) in Central China was built through prolonged subduction-accretion collision events and incorporates many exposures of exhumed ultrahigh-pressure (UHP) metamorphic rocks. We collected a large number of teleseismic and local earthquake data and performed a P-wave tomography and CCP stacking of receiver functions from this region. Our results reveal high-velocity horizontal anomalies at depths of 100-300 km beneath the QDOB, which may be related to the deep subduction or the delamination of the lower crust and lithosphere. We also imaged a low-velocity anomaly at depths of 200-400 km, which may be associated with mantle upwelling in this region. Based on a detailed analysis, we consider that the delamination of the lower crust and lithosphere might have contributed to the formation of the UHP rocks.