The synchronic Cenozoic subduction initiations in the west Pacific induced by the closure of the Neo-Tethys Ocean  

新特提斯洋闭合诱发西太平洋新生代俯冲起始

作　　者：Weidong Sun Lipeng Zhang He Li Xi Liu 孙卫东;张丽鹏;李贺;刘曦(Center of Deep Sea Research,Institute of Oceanology,Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]Center of Deep Sea Research,Institute of Oceanology,Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China [2]Laboratory for Marine Mineral Resources,Pilot National Laboratory for Marine Science and Technology(Qingdao),Qingdao 266237,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science Bulletin》2020年第24期2068-2071,M0005,共5页科学通报（英文版）

基　　金：supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (XDA22050103, XDB42020203);the National Key Research & Development Program of China (2016YFC0600408);the Taishan Scholar Program of Shandong (ts201712075);Aoshan Scholar Program of the Pilot National Laboratory for Marine Science and Technology (Qingdao)。

摘　　要：Subduction initiation is fundamental for the plate tectonics theory,which has drawn wide attentions[1-5].Ocean-continent transition[1],emergence of plume head[5],age contrast,e.g.,due to displacement of spreading ridges along transform fault[6],etc,have all been proposed as the main trigger of subduction initiation.Previous studies suggested two types of subduction initiations,namely spontaneous and induced[4].Induced subduction initiation was resulted from pre-existing plate convergence,whereas spontaneous subduction initiation was triggered by large lateral density contrasts occurring across profound lithospheric weaknesses[4],or by emerging of mantle plume head within the plate[5].板块俯冲起始机制是板块构造理论研究的难点.近年来,西太平洋新生代俯冲起始成为国际热点.前人通过多次国际大洋发现计划(IODP)钻探航次提出伊豆-小笠原-马里亚纳俯冲带是由于板块内部密度差异导致的自发俯冲起始.本文发现整个西太平洋板块年龄差异很大,但是新生代板块俯冲起始均发生在~52 Ma,略晚于太平洋板块转向的时代(~53 Ma).印度板块和澳大利亚板块的漂移速度于~55 Ma开始迅速降低,显示新特提斯洋闭合进入硬碰撞阶段,阻碍了澳大利亚板块和印度板块向北漂移的进程,致使与上述板块耦连的太平洋板块在杠杆作用下,改变了漂移方向,新俯冲沿走滑断层等薄弱地带起始,属"诱导俯冲起始".这种由老洋盆的闭合诱发新洋盆俯冲起始的过程正是板块构造体制循环往复的关键机制.

关 键 词：国际热点 西太平洋 板块构造理论 太平洋板块 印度板块 漂移速度 密度差异 板块内部 

分 类 号：P736.22[天文地球—海洋地质]