| 大洋板块拖曳窄条陆壳俯冲——大规模超高压变质形成的构造条件 |
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| 引用本文： | 石耀霖,范桃园.大洋板块拖曳窄条陆壳俯冲——大规模超高压变质形成的构造条件[J].地质学报,2002,76(1):77-82. |
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| 作者姓名： | 石耀霖 范桃园 |
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| 作者单位： | 中国科学院中国科学技术大学研究生院,北京,100039 |
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| 基金项目： | 国家自然科学基金资助项目(编号49774236) |
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| 摘 要： | 超高压变质岩生成问题中解决低密度大陆地壳深俯冲力学机制是一个关键问题。虽然俯冲地幔岩石可以裹携十几千米乃至几十千米尺度的陆壳块体到超高压变质深度，大规模的陆壳深俯冲需要特殊的构造条件。新西兰南岛北端研究表明，俯冲大洋板块能携带宽度达150km左右的窄条陆壳克服浮力达到超高压变质深度，而大陆板块碰撞的主体则浮在岩石圈上形成走滑断层。苏鲁-大别可能曾存在类似的构造条件：苏鲁西侧俯冲海洋板片首先拖曳苏鲁陆壳俯冲到超高压变质深度；随后大别以西俯冲大洋板片拖曳大别至超高压变质深度，而陆壳浮力导致苏鲁陆壳停止俯冲，飘浮的陆壳被北推而形成郯庐断裂；秦岭陆陆碰撞造山后大别超高压陆壳也折返；秦岭作为典型造山带，虽然不排除零星超高压变质的可能，但不具备大规模超高压变质的条件。
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| 关 键 词： | 超高压变质 新西兰 陆壳俯冲 大洋板块 构造作用 力学机制 |
| 修稿时间： | 2000年4月20日 |
Continental Sliver Subduction Driven by Oceanic Slab: Tectonic Settings for Large Scale Ultra-high Pressure Metamorphism |
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| SHI Yaolin,FAN Taoyuan Graduate School,Chinese Academy of Sciences,Beijing.Continental Sliver Subduction Driven by Oceanic Slab: Tectonic Settings for Large Scale Ultra-high Pressure Metamorphism[J].Acta Geologica Sinica,2002,76(1):77-82. |
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| Authors: | SHI Yaolin FAN Taoyuan Graduate School Chinese Academy of Sciences Beijing |
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| Abstract: | It is a critical problem in the mechanics of continental deep subduction why continental rocks of low density can be subducted to UHPM depths. Although it was suggested that continental blocks on the scale of tens of kilometers could be wrapped down to UHP depth by subducting mantle, large scale UHPM belts of continental deep subduction requires special tectonic settings. Studies on the northern South Island of New Zealand indicate that subducting oceanic slab can overcome the buoyancy and drag adjacent continental sliver up to about 150 km width to UHM depths, while the main body of continent can only float upon the mantle to produce strike-slip faults. Similar tectonic settings may exist in the Sulu-Dabie area. Oceanic slab west of Sulu dragged continental Sulu to UHPM depth first; then, oceanic slab west of Dabie dragged Dabie to UHPM depth, while Sulu, which lost the oceanic slab drag and under buoyancy, float up and produced the Tancheng-Lujiang strike-slip fault as the Yangtze block moved northward; finally, continental collision occurred in Qingling and Dabie UH-PM exhumed under buoyancy. As a typical orogeny of continental collision, Qingling has no condition for large scale UHPM formation, although scattered UHPM may not be excluded. |
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| Keywords: | Dabie-Sulu ultrahigh-pressure metamorphism New Zealand continental subduction |
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