超高压变质带中的变质不均一性  

Metamorphic Heterogeneity Within a Single Ultrahigh-pressure Belt

作　　者：姜为佳 刘贻灿[1,2] 

机构地区：[1]中国科学院壳幔物质与环境重点实验室,安徽合肥230026 [2]中国科学技术大学地球和空间科学学院,安徽合肥230026

出　　处：《地球科学与环境学报》2016年第2期160-171,共12页Journal of Earth Sciences and Environment

基　　金：国家重点基础研究发展计划("九七三"计划)项目(2015CB856104);国家自然科学基金项目(41273036)

摘　　要：不同造山带的榴辉岩和有关变质表壳岩石中柯石英及金刚石等标志性超高压变质矿物的发现,已证明陆壳岩石能俯冲到大于120km的地幔深度并折返至地表。超高压变质带中榴辉岩和相关的榴辉岩相岩石常常与具有低级变质矿物组合的岩石(如变质花岗岩、花岗片麻岩、变玄武岩或斜长角闪岩等)密切伴生,然而它们之间的相互关系和成因联系却一直是地质学家长期争议的焦点。查明这两类岩石的变质演化历史以及相互联系,对理解大陆的深俯冲及折返过程具有重要意义。在总结、分析若干陆陆碰撞造山带中变质不均一性的研究成果及成因解释的基础上,讨论了影响岩石保存超高压变质记录的若干关键因素,包括原岩性质、变质流体、构造变形、退变质作用等。Ultrahigh-pressure（UHP）index minerals,such as coesite and diamond in eclogites and related metamorphosed supracrustal rocks from various orogenic belts,suggest that continental crustal rocks can be subducted to mantle depths of more than 120 km and subsequently return to the surface.Furthermore,eclogites and related eclogite-facies rocks,and low-grade mineral assemblage-bearing rocks（i.e.metagranite,granitic gneiss,meta-basalt and amphibolite）commonly coexist in UHP metamorphic belts.However,their relationship and petrogenetic links between high-grade and lower grade assemblage-bearing rocks are often matter of debate.Hence,to clarify the metamorphic evolutionary histories and the correlation of the two groups of rocks plays a significant role in understanding the continental deep subduciton and exhumation processes.Some investigations on the metamorphic heterogeneity within a single UHP metamorphic belt were summarized.On this basis,several key factors such as protolith nature,metamorphic fluids,structural deformation and retrogression,which affect the preservation of UHP metamorphic records,were discussed.

关 键 词：超高压变质带 变质不均一性 大陆深俯冲 折返 碰撞造山带 榴辉岩 退变质作用 

分 类 号：P588.3[天文地球—岩石学]