大别山碰撞造山带的构造模型及其地质演化

    TECTONIC MODEL OF THE DABIESHAN COLLISION OROGEN AND ITS GEOLOGIC EVOLUTION

    • 摘要: 在大别山碰撞造山带东段可以划分出北淮阳地块、岳西地块、四望地块3个构造单元。岳西地块中前寒武纪地质体普遍遭受过高压变质作用,构成一个高压—超高压变质地块的“核”,其上、下盘则是低压变质或未变质地块的“壳”,在空间上呈现出一种“夹心饼”式构造格局。高压变质地块上部边界的正断层和下部边界的逆断层是其“挤出”抬升机制的直接标志。大别山造山带“夹心饼”式构造模型的形成与古生代时期扬子板块向中朝板块的俯冲作用及中生代时期两大板块碰撞并快速抬升作用密切相关

       

      Abstract: The eastern sector of the Dabieshan collision orogen may be divided into three tectonic units:the North Huaiyang block, Yuexi block and Siwang block.The Precambrian geologic bodies in the Yuexi block,which generally underwent high-pressure metamorphism,form the“core"of a high-pressure(HP)-ultra-high-pressure(UHP)metamorphic block,and its hanging wall and foot-wall are low-pressure metamorphic or unmetamorphosed layers, displaying a “sandwich"-style tectonic framework in space.The normal fault at the upper boundary and the reversed fault at the lower boundary of the HP metamorphic block are the direct indications of its “extrusion" and uplifting mechanism.The formation of the “sandwich"-style tectonic model of the Dabieshan orogen was closely related to Paleozoic subduction of the Yangtze plate towards the Sino-Korean plate and Mesozoic collision and subsequent rapid uplifting of the two plates.

       

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