| Deep geodynamics of far field interconti- nental back-arc extension: Formation of Cenozoic volcanoes in northeastern China |
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| 作者姓名： | 石耀霖 张健 |
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| 作者单位： | Laboratory of Computational Geodynamics，Graduate School of Chinese Academy of Sciences，Beijing 100039，China，Laboratory of Computational Geodynamics，Graduate School of Chinese Academy of Sciences，Beijing 100039，China |
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| 摘 要： | Introduction Northeastem China has the most strong Cenozoic volcanism in China (Liu, 1999), where dis-tributes more than 500 Cenozoic volcanoes, including sleeping volcanoes of Tianchi Lake (Celes-tial Pond) of Changbai Mountain, and Wudalianchi (Five linked Lakes) (LIU, 1999). Vo lcano ofTianchi Lake of Changbai Mountain consists of basaltic rocks of shield-forming stage andtrachytes and pantellerites in cone-forming stage. It is suggested by study of REE, incompatibleelements a…
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Deep geodynamics of far field intercontinental back-arc extension:Formation of Cenozoic volcanoes in northeastern China |
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| SHI Yao-lin ZHANG Jian Laboratory of Computational Geodynamics,Graduate School of Chinese Academy of Sciences,Beijing ,China.Deep geodynamics of far field interconti- nental back-arc extension: Formation of Cenozoic volcanoes in northeastern China[J].Acta Seismologica Sinica(English Edition),2004,17(Z1). |
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| Authors: | SHI Yao-lin ZHANG Jian Laboratory of Computational Geodynamics Graduate School of Chinese Academy of Sciences Beijing China |
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| Institution: | Laboratory of Computational Geodynamics, Graduate School of Chinese Academy of Sciences, Beijing 100039,China |
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| Abstract: | There are three cases of variation of trench location possible to occur during subduction: trench fixed, trench advancing, and trench retreating. Retreat of trench may lead to back-arc extension. The Pacific plate subducts at low angle beneath the Eurasia plate, tomographic results indicate that the subducted Pacific slab does not penetrate the 670 km discontinuity, instead, it is lying flat above the interface. The flattening occurred about 28 Ma ago. Geodynamic computation suggests: when the frontier of the subducted slab reaches the phase boundary of lower and upper mantle, it may be hindered and turn flat lying above the boundary, facilitates the retreat of trench and back-arc extension. Volcanism in northeastern China is likely a product of such retreat of subduction, far field back-arc extension, and melting due to reduce of pressure while mantle upwelling. |
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| Keywords: | back-arc basin Cenozoic volcano geodynamics northeastem China |
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