西准噶尔蛇绿岩:古大洋俯冲增生过程的记录  

Ophiolite in West Junggar:Records of the subduction-accretion process in ancient ocean

作　　者：杨高学[1,2] 朱钊 刘晓宇 李海 佟丽莉[1,2] YANG Gaoxue;ZHU Zhao;LIU Xiaoyu;LI Hai;TONG Lili(School of Earth Sciences and Resources,Chang'an University,Xi'an,Shaanri 710054,China;Key Laboratory of Western China's Mineral Resources and Geological Engineering,Ministry of Education,Xi'an,Shaanri 710054,China;Northwest Geological Erploration Institute of China Metallurgical Geology Bureau,Xi'an,Shaanri 710l19,China;School of Earth Sciences and Engineering,Xi'an Shiyou University,Xi'an,Shaanri 710065,China)

机构地区：[1]长安大学地球科学与资源学院,陕西西安710054 [2]西部矿产资源与地质工程教育部重点实验室,陕西西安710054 [3]中国冶金地质总局西北地质勘查院,陕西西安710119 [4]西安石油大学地球科学与工程学院,陕西西安710065

出　　处：《地质学报》2023年第6期2054-2066,共13页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号41303027);陕西省自然科学基金项目(编号2023-JC-YB-236,2023-JC-QN-0318)联合资助的成果。

摘　　要：蛇绿岩记录了大洋岩石圈形成、演化、消亡的全过程,是刻画区域板块构造和洋-陆格局演化的关键证据。本文通过系统梳理前人相关研究,总结西准噶尔蛇绿岩最新研究成果,探讨大陆地壳增生方式、恢复古大洋演化历史,从而对西准噶尔构造体制转化提供新制约。西准噶尔地区发育多条震旦纪—石炭纪被构造肢解的蛇绿岩带,具有典型的岩块-基质结构,绝大多数蛇绿岩包括正常洋壳组分和海山/大洋高原残片,其中基性岩具有MORB和OIB的地球化学特征。基于前人研究,本文认为在西准噶尔古大洋发育过程中,发育不同时代与地幔柱有关的海山/大洋高原,同时存在增生型和侵蚀型两类汇聚板块边界。另外,大洋高原增生不仅是大陆地壳增生的有效途径之一,还可能诱发俯冲极性反转和传递。而在大洋高原形成初期,还可能存在地幔柱诱发俯冲起始机制。Ophiolite records the whole process of formation,evolution and extinction of the oceanic lithosphere,and is a key evidence for studying the regional plate tectonics and ocean-continent frame.This study summarizes the latest research on ophiolite in West Junggar,with the aim of discussing continental crust growth style and recovering the ancient oceanic evolution history,and provideing new constraints on the tectonic regime transition of the West Junggar.A number of tectonically dismembered ophiolite belts with a typical block-matrix structure are developed in the West Junggar region.The ophiolites mainly include oceanic crust components and seamount/oceanic plateau fragments;the mafic rocks in the ophiolites are characterized by MORB and OIB geochemistry.Based on previous research,this study suggests that the seamounts/oceanic plateaus with different ages are related to the mantle plume and developed in different evolution stages of the West Junggar Ocean.At the same time,there are two types of convergent plate boundaries,including accretionary and erosional plate margins.In addition,oceanic plateau accretion is not only one of the effective ways of continental crust growth,but may also induce subduction polarity reversal and subduction transference.Furthermore,there may also be mantle plume induced subduction initiation mechanism at the early stage of oceanic plateau formation in West Junggar.

关 键 词：大地构造 蛇绿岩 海山 俯冲起始 西准噶尔 

分 类 号：P736.22[天文地球—海洋地质] P542[天文地球—海洋科学]