板块俯冲侵蚀雅浦岛弧的地形制约

发布时间：2018-04-05 15:18

本文选题：俯冲侵蚀　切入点：沟弧间距　出处：《海洋地质与第四纪地质》2017年01期

【摘要】：俯冲侵蚀是一种将地壳及岛弧物质从弧前搬运走的地质过程,会导致弧前物质的缺失,这种地质过程普遍地出现在汇聚型板块边缘。雅浦海沟位于加罗林板块与菲律宾海板块之间,是一个活跃的俯冲带。利用2015年中科院海洋所在西太平洋雅浦海采集的最新的多波束和地震数据,给出了雅浦海沟发生俯冲侵蚀的直接证据:(1)雅浦海沟具有异常短的沟弧间距(41km);(2)海沟呈不对称的"V"字形,增生楔缺失;(3)俯冲板片基底起伏程度大,加罗林洋底高原上洋脊、海山、地垒地堑构造发育;(4)海沟内壁斜坡较陡,弧前斜坡坡度的平均值约8.69°,雅浦海沟的弧前增生楔缺失。揭示了雅浦海沟南北两侧俯冲侵蚀模式的差异,北部的俯冲侵蚀主要由于洋底高原上地垒地堑与上覆板块的摩擦造成,板块之间可能不是直接接触,存在"剥蚀带";南部的俯冲侵蚀主要由于洋底高原上的海山与上覆板块的摩擦造成,板块之间可能是直接接触的。
[Abstract]:Subduction is a geological process in which the crustal and island arc materials are transported from the front of the arc, which leads to the absence of the material in front of the arc. This geological process generally occurs at the margin of the convergent plate.The Yap Trench is an active subduction zone between the Garlin Plate and the Philippine Sea Plate.Using the latest multi-beam and seismic data from the Yapu Sea in the western Pacific Ocean, where the Chinese Academy of Sciences ocean was located in 2015,The direct evidence of subduction erosion in the Yapu trench is: 1) the Yapu trench has an unusually short furrow arc spacing of 41 km2 and 2) the trench presents an asymmetric "V" shape, the accretionary wedge is absent and the basement of the subduction plate is large and undulating, and the upper ridge and seamounts on the plateau of the Carolyn ocean floor.The slope of the inner wall of the trench is steep, the average slope of the front slope is about 8.69 掳, and the accretive wedge of the Yapu trench is absent.It is revealed that the north and south subduction patterns of the Yapu trench are different. The subduction erosion in the north is mainly caused by the friction between the crust graben and the overlying plate on the ocean floor plateau, and the plate may not be in direct contact with each other.The subduction erosion in the south is mainly caused by the friction between seamounts on the ocean floor plateau and the overlying plates, which may be in direct contact with each other.
【作者单位】：中国科学院海洋研究所海洋地质与环境重点实验室;中国科学院大学;青岛海洋科学与技术国家实验室海洋地质过程与环境功能实验室;青岛海洋科学与技术国家实验室海洋矿床资源评价功能实验室;
【基金】：中国科学院战略性先导科技专项(A类)资助(XDA11030102);中国科学院“海山成因、演化与深部物质循环”科技创新与交叉团队项目全球变化与海气相互作用专项(GASIGEOGE-02) 国家自然科学基金项目(41506059,41476046)
【分类号】：P736.1

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