大别山超高压变质带的构造背景  

TECTONIC SETTING OF THE ULTRA-HIGH PRESSURE METAMORPHIC BELT IN THE DABIE MOUNTAINS

作　　者：江来利[1] 徐树桐[1] 刘贻灿[1] 苏文[1] 

机构地区：[1]安徽省地质科学研究所

出　　处：《地质论评》1995年第3期229-237,共9页Geological Review

基　　金：国家自然科学基金 (编号:49172126);安徽省地质矿产局科研基金

摘　　要：大别山南部的超高压变质带具有特征的榴辉岩相矿物组合。榴辉岩的岩石化学及稀土元素特征及其伴生的岩石组合,表明这个带是以陆壳成分为主混有少量上地幔及洋壳成分的混杂岩。榴辉岩相围岩和大别群具有不同的变质和变形特征。超高压变质带形成于扬子和中朝板块大陆碰撞的构造环境,是扬子板块陆壳向北俯冲到一定深度的变质产物。The ultra-high pressure metamorphic belt in the southern part of the Dabie Mountains is mainly distributed in the subducted basement of the Yangtze plate (the Dabie Group) and composed of eclogite with small amounts of ultramafic and jadeite-quartzite blocks and their country rocks. Their mineral assemblages, especially the inclusions of coesites and diamonds suggest that these rocks underwent an ultra-high pressure eclogite facies metamorphism. The chemical corn-positions and REE contents of the eclogites and the characteristics of the rock association including garnet-peridotite, and jadeite-quartzite indicate that the belt is a tectonic melange one composed many of continental crustal rocks mixed with some mentle-derived and oceanic crustal rocks. The formation of the ultra-high pressure metamorphic belt is related to the collision between the Sino-Korean and Yangtze plates during the early Mesozoic, and was the product of northward subduction of the continental crust of the Yangtze plate to a depth greater than 90 km. The ultra-high pressure metamorphic belt was uplifted rapidly by obduction to the middle crust in the process of continuous subduction-obduction in the collisional tectonic setting, so it was an allochthon thrust on the subducted basement of the Yangtze plate.

关 键 词：大别山 榴辉岩相 混合岩带 变质带 变质岩 

分 类 号：P588.35[天文地球—岩石学]