Changbaishan volcanism in northeast China linked to subduction-induced mantle upwelling
Changbaishan volcanism in northeast China linked to subduction-induced mantle upwelling
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DOI：
10.1038/ngeo2166
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发表时间：
2014-06
影响因子：
18.3
通讯作者：
Youcai Tang;M. Obayashi;F. Niu;S. Grand;Yongshun John Chen;H. Kawakatsu;S. Tanaka;J. Ning
中科院分区：
文献类型：
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作者：
Youcai Tang;M. Obayashi;F. Niu;S. Grand;Yongshun John Chen;H. Kawakatsu;S. Tanaka;J. Ning
远离板块边缘发生的火山活动很难用当前的板块构造范式来解释。长白山火山群位于中国和朝鲜边境，距日本海沟俯冲带约1300公里，不太可能是地幔底部热边界层上升的地幔柱形成的。在这里，我们使用 NECESSArray 实验获得的地震图像和三维波形建模结果来识别长白山地幔中缓慢、连续的地震异常。该异常现象从 660 公里以下的深度延伸至长白山下方的地表，并发生在静止俯冲的太平洋板块的间隙内。我们认为，该异常现象代表了炽热且有浮力的岩石圈下地幔，它被夹带在太平洋板块下沉的岩石圈下方，现在正通过俯冲板片的间隙逸出。我们认为，这种俯冲引起的上升流过程产生了减压熔融，为长白山火山提供了水源。俯冲引起的上升流也可以解释在其他俯冲带观察到的弧后火山活动。
Volcanism that occurs far from plate margins is difficult to explain with the current paradigm of plate tectonics. The Changbaishan volcanic complex, located on the border between China and North Korea, lies approximately 1,300 km away from the Japan Trench subduction zone and is unlikely to result from a mantle plume rising from a thermal boundary layer at the base of the mantle. Here we use seismic images and three-dimensional waveform modelling results obtained from the NECESSArray experiment to identify a slow, continuous seismic anomaly in the mantle beneath Changbaishan. The anomaly extends from just below 660 km depth to the surface beneath Changbaishan and occurs within a gap in the stagnant subducted Pacific Plate. We propose that the anomaly represents hot and buoyant sub-lithospheric mantle that has been entrained beneath the sinking lithosphere of the Pacific Plate and is now escaping through a gap in the subducting slab. We suggest that this subduction-induced upwelling process produces decompression melting that feeds the Changbaishan volcanoes. Subduction-induced upwelling may also explain back-arc volcanism observed at other subduction zones.