| 区域变质作用与中国大陆地壳的形成与演化 |
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| 引用本文： | 耿元生,沈其韩,杜利林,宋会侠.区域变质作用与中国大陆地壳的形成与演化[J].岩石学报,2016,32(9):2579-2608. |
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| 作者姓名： | 耿元生 沈其韩 杜利林 宋会侠 |
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| 作者单位： | 中国地质科学院地质研究所, 北京 100037,中国地质科学院地质研究所, 北京 100037,中国地质科学院地质研究所, 北京 100037,中国地质科学院地质研究所, 北京 100037 |
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| 基金项目： | 本文受中国地质调查局工作项目（1212010811048、1212011120427）资助. |
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| 摘 要： | 在编制1∶500万中国变质地质图的基础上,本文总结了中国主要变质带的演化以及各变质带与中国大陆地壳形成演化之间的内在联系。虽然在华北和华南克拉通都有古太古代到中太古代的变质年代记录,但是由于后期改造其变质作用的特点及与区域构造背景的联系已难以追索。新太古代末-古元古代初期的变质作用在华北克拉通表现最明显,这期变质作用紧随大规模的TTG岩浆作用,普遍具有逆时针的P-T演化轨迹,反映了地幔柱主导的岩浆-变质事件特点。古元古代晚期的变质事件在华北、华南、塔里木克拉通都有强烈反映。这期变质作用以形成具有顺时针P-T演化轨迹的高压麻粒岩为特点,与形成Columbia超大陆的一些造山带的特点类似,但是这三个不同克拉通在与Columbia聚合的时间和空间方位上存在差异。华南克拉通是相对年轻的克拉通,是沿新元古代江南造山带扬子和华夏地块拼合的产物。新元古代江南造山带的火山岩形成时代和变质作用程度从北东向南西迁移,反映了造山过程逐渐迁移和剪刀式闭合的特点。形成华南克拉通后,在其东南缘又先后经历了加里东期和印支期的变质改造,并且由北西向南东变质带从加里东期转变为印支期,但是这两期变质作用的构造背景尚不很清楚。中国南北大陆的聚合首先从西昆仑-阿尔金-北祁连-北秦岭-桐柏开始,所反映的变质作用是早古生代的蓝片岩相和榴辉岩相变质岩相伴产出,表明经历了从洋壳俯冲到陆陆碰撞的演化过程。中国东部的南北大陆到印支期才最终汇聚,相应的变质作用以南部出现高压蓝片岩相、北部出现超高压的榴辉岩相变质带为特点,表明南方大陆向北方大陆的俯冲。超高压带内普遍含有柯石英,意味着大规模的陆壳深俯冲。华北克拉通和塔里木克拉通以北的中亚造山带内存在多条从早古生代到晚古生代的变质带和多条蓝片岩相变质带,表明这是一个由多阶段、多条变质带组成的造山区。但是其变质作用的空间和时间演化还有待进一步深入。青藏高原变质带具有北老南新的空间分布特点,最北部的印支期龙木错-双湖-澜沧江变质带反映了原特提斯和古特提斯洋的碰撞拼合过程,北部的燕山期班公湖-怒江变质带和中部的喜马拉雅早期雅鲁藏布江变质带反映了新特提斯洋的两次碰撞拼合过程,南部喜马拉雅晚期的高喜马拉雅变质带反映了印度板块向北俯冲导致的高原快速隆升过程。
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| 关 键 词： | 区域变质作用 变质单元 P-T轨迹 变质事件 地壳生长和演化 陆块聚合 |
| 收稿时间： | 2016/4/28 0:00:00 |
| 修稿时间： | 8/1/2016 12:00:00 AM |
Regional metamorphism and continental growth and assembly in China |
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| GENG YuanSheng,SHEN QiHan,DU LiLin and SONG HuiXia.Regional metamorphism and continental growth and assembly in China[J].Acta Petrologica Sinica,2016,32(9):2579-2608. |
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| Authors: | GENG YuanSheng SHEN QiHan DU LiLin and SONG HuiXia |
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| Institution: | Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China,Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China and Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China |
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| Abstract: | Based on compilation of the Metamorphic Geological Map of China (at the scale of 1:5 million), we have summarized in this paper the evolutionary history of the major metamorphic belts in China and the intrinsic relationship between the metamorphic belts and continental formation and evolution in China. Although the North China and South China cratons keep the metamorphic ages from Paleoarchean to Mesoarchean, it is difficult for us to trace the link between the original metamorphism and tectonic setting due to intensive overprinting of late deformation and metamorphism. Late Neoarchean to Early Paleoproterozoic metamorphism is extensive in the North China Craton which displayed the anti-clockwise P-T paths following the widespread TTG magmatism, suggesting that mantle plumes led to the magmatism and metamorphism. The Late Paleoproterozoic metamorphic events, occurring widely in North China, South China and Tarim cratons, are represented by the high-pressure granulite facies metamorphism with clockwise P-T path and are similar to the metamorphic events in typical orogens in Columbian supercontinent of the same period. However, there are still some different aspects in time and space for the three cratons (North China, South China and Tarim cratons) during their amalgamation with Columbian supercontinent. South China craton is relatively young and was assembled by Yangtze and Cathaysia blocks along the Jiangnan Orogen in Neoproterozoic. Younging of magmatism and decreasing intensity of metamorphism from the northeast to southwest along the Jiangnan Orogen reflected the migration of orogenic process in this belt. After formation, the South China Craton underwent the Caledonian and Indosinian metamorphism from the northwest to southeast along its'' southeastern margin, but the tectonic settings for metamorphism are unclear. The amalgamation of the North China and South China cratons initiated along the western Kunlun-North Qilian-North Qinling-Tongbai belt, and metamorphism along this belt was represented by the Early Palaeozoic blueschist and eclogite facies, indicating the evolutionary process from subduction to continent-continent collision. In the eastern China, the North China and South China cratons amalgamated along the Dabie-Sulu Orogen in Indosinian, when the blueschist and eclogite facies rocks occurred at the south and north of the belt, respectively, suggesting the South China Craton subducted beneath the North China Craton. Coesite is widely distributed in this ultra-high pressure belt, implying the large scale continental subduction. The Central Asian Orogenic Belt, located to the north of the North China Craton and Tarim Craton, contains several metamorphic belts from Early to Late Paleozoic with local blueschist facies metamorphism, which indicate that the Central Asian Orogenic Belt is an orogenic region including several metamorphic belts of different stages of metamorphism. However, the time and space evolution of this metamorphic belt still need further research. The Tibet Plateau metamorphic belts change from old to young in space from north to south. The northern most Indosinian Lungmu Co-Shuanghu-Lancangjiang metamorphic belt represented the collisional process of Paleo-Tethys. The north Yanshanian Bangong Co-Nujiang metamorphic belt and the middle Early Himalayan Yarlung Zangbo belt exhibited two collisional processes of Neo-Tethys. However, the south High Himalayan metamorphic belt in Late Himalayan represented quick uplift process resulted from the north-ward subduction of the Indian Plate to Eurasia Plate. |
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| Keywords: | Regional metamorphism Metamorphic unit P-T path Metamorphic event Continent formation and evolution Amalgamation of continental blocks |
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