伊豆−博宁−马里亚纳岛弧地壳厚度分布及其对岩浆活动的指示  

Crustal thickness variations of the Izu-Bonin-Mariana Arc and their implications for arc magmatism

作　　者：白永良[1] 杨慧良[2] 张迪娅 容伊霖 董冬冬[3] 吴时国 BAI Yongliang;YANG Huiliang;ZHANG Diya;RONG Yilin;DONG Dongdong;WU Shiguo(College of Oceanography and Space Informatics,China University of Petroleum,Qingdao 266580,China;Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266071,China;Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Institute of Deep-sea Science and Engineering,Chinese Academy of Sciences,Sanya 572000,China)

机构地区：[1]中国石油大学(华东)海洋与空间信息学院,青岛266580 [2]中国地质调查局青岛海洋地质研究所,青岛266071 [3]中国科学院海洋研究所,中国科学院海洋地质与环境重点实验室,青岛266071 [4]中国科学院深海科学与工程研究所,三亚572000

出　　处：《海洋地质与第四纪地质》2021年第1期158-165,共8页Marine Geology & Quaternary Geology

基　　金：山东省自然科学基金项目“伊豆−博宁−马里亚纳俯冲带岛弧增生速率及其控制因素研究”(ZR2020MD065);国家自然科学基金项目“西太平洋典型俯冲带的流体活动及其对孕震机理的影响”(91958211)。

摘　　要：数值模拟研究认为洋底高原/洋脊俯冲和弧后扩张能够有效影响俯冲带岩浆活动和岛弧地壳增生。本文以伊豆−博宁−马里亚纳(IBM)俯冲带为实例,论证该结论的有效性。以卫星测高反演重力异常为基础,通过构建地球不同圈层密度模型,反演得到IBM俯冲带莫霍面埋深。本文的莫霍面埋深反演结果与地震解释结果具有一致的分布趋势。结合开源水深和沉积层厚度数据,给出了IBM俯冲带地壳厚度分布。IBM岛弧地壳体积沿走向的分布特征表明:①小笠原洋底高原和相对较小规模达顿洋脊的俯冲,都能够使得相应位置的岛弧变窄、地壳变厚、体积增大;②马里亚纳海槽扩张显著降低了岛弧地壳体积的增生量。Numerical simulations suggest that plateau/ridge subduction and back-arc spreading would influence magmatism and island-arc crustal growth subduction-zone.In this paper,we take the Izu-Bonin-Mariana(IBM)subduction zone paper as a case to test the above observation.Moho depth variations are estimated based on Inversed gravity anomaly by satellite altimetry and density modelling for different layers,and the trend of the Moho inversion result can well match the seismic interpretations.Crustal thickness variations are mapped based on gravity-inversed Moho,open-source topography and bathymetry as well as sediment thickness.The island-arc crustal volume variations along strike indicate that(1)the subduction of the Ogasawara Plateau and the Dutton Ridge necked and thickened the arc crust,and they also increased the arc crust volume,(2)the opening of the Marian Trough reduced substantially the island-arc crustal growth.

关 键 词：伊豆−博宁−马里亚纳岛弧 重力反演 地壳厚度 弧后扩张 洋底高原/洋脊俯冲 

分 类 号：P738.1[天文地球—海洋地质]