中国三条高温高压变质带及其地质意义

Three Important High Pressure and High Temperature Metamorphic Zones in China and Their Geotectonic Significance

高温高压变质岩是指高温（热）榴辉岩－高压麻粒岩－石榴角闪岩的变质序列。其形成的大地构造环境为陆－陆碰撞或陆－弧碰撞带，而不形成于与洋壳有关的汇聚性板块边缘。中国境内有三条典型的高温高压变质带，它们是桑干－承德变质带，大别山－苏鲁变质带和南迦巴瓦变质带。变质时代分别是２５００Ｍａ，２１０～２４０Ｍａ和１７～１４Ｍａ。大别山－苏鲁变质带是中生代陆－陆碰撞带根部变质杂岩，代表了华北与扬子两个陆块拼合的界限。年轻的南迦巴瓦变质带是陆－弧碰撞带变质岩系，高压麻粒岩除了在冈第斯岩浆弧的根部以透镜体出露外，主要代表了被掀斜抬升的印度陆块的基底下地壳岩石。桑干－承德变质带是华北克拉通内的高压麻粒岩－榴辉岩转换相的变质带，表明在晚太古代已有与显生宙相似的形成高压变质带的大地构造机制。

High pressure and high temperature metamorphic zone, including high temperature (hot) eclogite high pressure granulite garnet amphibolite,are only formed in continent continent collision and arc continent collision geotectonic setting, but not in convergent plate margin related to ocean crust. There are three important typical high pressure and high temperature metamorphic zones in China:the Sanggan, Dabieshan Sulu and Najiabawa metamorphic zones. Their metamorphic ages are 2500 Ma, 210￣240 Ma and 17￣14 Ma. The Dabieshan Sulu metamorphic zone is a terrane of Mesozoic metamorphic complex in continent continent collisional root zone, representing the suture between the North China plate and Yangtze plate. The youngest Nanjiabawa metamorphic zone is composed of arc continent collisional metamorphic complex. High pressure granulites, except a few amount that occur in root of the Gangdisi magmatic arc, mainly represent the lower crust rocks of the Indian plate. They were obliqued and thrusted up during collision process. The Sanggan Chengde metamorphic zone is the late Archaean metamorphic zone of granulite eclogite transitional facies in the North China craton, which indicates that the tectonic mechanism in early Precambrian period is possibly similar to that of the Phanerozoic plate tectonics.