南海东部马尼拉俯冲带的地壳结构和俯冲过程

发布时间：2018-08-09 14:19

【摘要】：全球汇聚板块边缘是产生8级以上大地震和破坏性海啸的地方,一直以来是全球科学家关注的焦点和热点区域。马尼拉俯冲带位于南海东部,也是许多地震、海啸和活火山活跃的区域。本文依据以往穿过马尼拉俯冲带的多条多道反射地震测线和海底地震仪剖面数据,分析了马尼拉俯冲带海沟沉积物充填厚度变化、增生楔宽度变化、海底变形特征以及地壳速度结构变化,提出马尼拉俯冲带具有明显的分段特征,分为北吕宋区段、海山链区段和南部西吕宋区段。不同区段的俯冲过程明显不同,提出俯冲增生和俯冲剥蚀(构造剥蚀)两种机制分别控制了该俯冲带的南、北区段。北段主要受到俯冲增生机制的控制,在海沟和弧前盆地之间形成巨大的增生楔构造,在南海北部大陆边缘10~15km厚的减薄陆壳不断俯冲作用下,引起许多与俯冲有关的地震活动和构造变形。南段海山链区段海底地形复杂和粗糙,在俯冲增生、剥蚀或构造剥蚀的联合控制下,5~6km厚大洋板块不断俯冲形成较小的增生楔结构,部分沉积物可能随着板块的俯冲被拖曳到板块边界的深部。
[Abstract]:The edge of the global convergence plate is the place where large earthquakes and destructive tsunamis with magnitude 8 or above occurred, and has always been the focus and hot spot of global scientists. The Manila subduction zone, located in the eastern part of the South China Sea, is also home to many earthquakes, tsunamis and active volcanoes. Based on the data of multi-channel reflection seismograph and submarine seismograph, the variation of sediment filling thickness and width of accretive wedge in Manila subduction zone are analyzed in this paper. According to the characteristics of submarine deformation and the variation of crustal velocity structure, the Manila subduction zone has obvious segmental features, which can be divided into the northern Luzon section, the seamount chain section and the southern west Luzon section. The subduction processes of different subduction zones are obviously different. Two mechanisms of subduction hyperplasia and subduction denudation (structural denudation) are proposed to control the southern and northern segments of the subduction zone respectively. The northern segment is mainly controlled by the mechanism of subduction and accretion, and a huge accretive wedge structure is formed between the trench and the forearc basin. Under the continuous subduction of the 10~15km thickness of the continental margin in the northern part of the South China Sea, Causes many subduction related seismic activities and tectonic deformation. The sea floor of the southern seamount chain section is complex and rough. Under the combined control of subduction, erosion or structural erosion, the oceanic plate with a thickness of 5 ~ 6 km is continuously subducted to form a smaller accretive wedge structure. Some sediments may be towed to the deep part of the plate boundary with the subduction of the plate.
【作者单位】：中国科学院南海海洋研究所边缘海地质重点实验室;海底科学与探测技术教育部重点实验室中国海洋大学海洋地球科学学院;青岛海洋科学与技术国家实验室海洋地质功能实验室;
【基金】：广州市科技计划项目科学研究专项(一般项目)(201607010220)
【分类号】：P736.1

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