拆离断层与大洋核杂岩:一种新的海底扩张模式  

Detachment Fault and Oceanic Core Complex:A New Mode of Seafloor Spreading

作　　者：余星[1] 初凤友[1] 董彦辉[1] 李小虎[1] 唐立梅[1] 

机构地区：[1]国家海洋局第二海洋研究所国家海洋局海底科学重点实验室,浙江杭州310012

出　　处：《地球科学（中国地质大学学报）》2013年第5期995-1004,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家海洋局青年基金项目(No.2011304);国家重点基础研究发展计划(No.2013CB429705);浙江省青年基金项目(No.LQ12D02001);国家基本科研业务费专项(No.JT1001);海洋公益性行业科研专项(No.201005003);大洋"十二五"项目(No.DY125-12-R-04)

摘　　要：近年来,一种新的海底扩张模式引起了广大科学家的重视.它与一般的岩浆型洋中脊扩张不同,属于一种非岩浆或贫岩浆的海底扩张方式,扩张作用主要通过拆离断层的滑移来实现.拆离断层使下盘的深部洋壳或上地幔岩石出露到海底,形成了大洋核杂岩,通常表面呈现龟背似的波瓦状穹隆,或称巨型窗棱构造.从拆离断层、大洋核杂岩等基本概念入手,综述这种新型海底扩张模式的特征,总结归纳大洋核杂岩的分布状况及识别手段,探讨其地质意义以及对海底热液活动、成矿的积极影响.A new type of seafloor spreading mode has recently been well acknowledged among earth science community.It is different from normal magmatic spreading ridge.It is usually found along the slow or ultraslow spreading ridge where the segment is amagmatic or depleted in magma.The plate separation is mostly accommodated by detachment fault slipping.The low-angle large-offset detachment fault will uplift the footwall and exhume lower crust and upper mantle rocks,which is called oceanic core complex.The oceanic core complex,also named as megamullion,is often marked by corrugations and striations parallel to the extension direction.This paper presents the characteristics of this new kind of spreading mode based on in-depth argument about terminology of detachment fault and oceanic core complex.A distribution map of the known oceanic core complex has been composed.The possible methods and techniques that can be used to recognize oceanic core complexes are also discussed in this study,and so does the significance of the new findings and its influence on seafloor hydrothermal activity and mineral deposit.

关 键 词：拆离断层 大洋核杂岩 巨型窗棱构造 海底扩张 构造 热液活动 岩石学 

分 类 号：P736.1[天文地球—海洋地质]