北山古堡泉地区榴辉岩变质作用P-T-t轨迹及构造意义  

P-T-t Path and Tectonic Implications of Gubaoquan Eclogite from Beishan Region

作　　者：陈言飞 邵兆刚[1] 陈宣华[1] 李杰[1,2] 王叶[1] 王洛娟 苏和 CHEN Yan-fei;SHAO Zhao-gang;CHEN Xuan-hua;LI Jie;WANG Ye;WANG Luo-juan;SU He(Chinese Academy of Geological Sciences,Beijing 100037;School of Earth Sciences and Resources,China University of Geosciences(Beijing),Beijing 100083)

机构地区：[1]中国地质科学院,北京100037 [2]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地球学报》2022年第6期895-908,共14页Acta Geoscientica Sinica

基　　金：中国地质调查局地质调查项目(编号:DD20190011;DD20221643);国家重点研发计划(编号:2018YFC0603700);中国石油长庆油田公司横向项目(编号:2021DA0404);中国地质科学院基本科研业务费项目(编号:JKY202011)联合资助。

摘　　要：北山造山带南部古堡泉地区出露榴辉岩,对榴辉岩变质作用P-T-t轨迹的研究,有助于了解北山地区的构造演化历史。本文对古堡泉地区的榴辉岩开展了岩石学、矿物化学和锆石U-Pb年代学的研究。研究表明,榴辉岩原岩形成时代为860 Ma,进变质或近峰期变质时代为~465 Ma,岩石具有顺时针P-T-t轨迹,经历了较陡的升温升压过程后到达峰期高压榴辉岩相,峰期变质条件分别为P>22 kbar、T=660~700℃,之后经历了近等温降压过程。榴辉岩是大陆地壳快速俯冲形成,俯冲深度达80 km,之后又经历了快速的折返。The P-T-t path of eclogite from the Gubaoquan area,south of Beishan Orogen,is used to track the tectonic history of the Beishan region.This paper presents novel petrology,mineral chemistry,and geochronology of Beishan eclogite.Zircon U-Pb data show that the protolith of eclogite formed at~860 Ma with a prograde or near-peak metamorphic age of~465 Ma.The P-T-t path of the eclogite was clockwise,with an early steep temperature and pressure rise process,subsequent eclogite-facies metamorphism with conditions of>22 kbar and 660−700℃,and a late isothermal retrograde decompression process.The eclogite was formed by rapid subduction of continental crust,with a depth of 80 km,followed by rapid exhumation.

关 键 词：榴辉岩 P-T-T轨迹 构造意义 北山地区 

分 类 号：P588.3[天文地球—岩石学]