| 羌塘中部高压变质带的形成过程 |
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| 引用本文： | 董永胜,李才,施建荣,张修政,王生云.羌塘中部高压变质带的形成过程[J].岩石学报,2010,26(7):2099-2105. |
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| 作者姓名： | 董永胜 李才 施建荣 张修政 王生云 |
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| 作者单位： | 吉林大学地球科学学院,长春,130061 |
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| 基金项目： | 国家自然科学基金（40872146、40672147）与中国地质调查局项目（1212010811048、1212010818015） |
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| 摘 要： | 羌塘中部高压变质带由榴辉岩、石榴石白云母片岩和蓝片岩等组成,与蛇绿混杂岩、晚古生代浅变质地层岩片等共同构成了龙木错-双湖板块缝合带这一构造混杂岩带,是伴随古特提斯洋闭合的深俯冲作用及后期构造作用的产物。通过对其野外地质特征、不同岩石类型岩石学、矿物学以及同位素年代学等的研究,确认榴辉岩和石榴石白云母片岩在早期分别经历了各自的形成过程,在榴辉岩形成之后的折返过程中二者共同构成了高压变质带,并且在折返过程中榴辉岩发生蓝片岩相退变质作用,同时导致了带内蓝片岩的形成。同位素年代学研究结果表明,龙木错-双湖板块缝合带闭合过程中的榴辉岩相变质作用发生于240Ma左右,折返过程中的蓝片岩相退变质作用及蓝片岩的形成应在220～200Ma,高压变质带最终在214Ma之前抬升出露地表。
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| 关 键 词： | 高压变质带 榴辉岩相 蓝片岩相 构造侵位 羌塘 |
| 收稿时间： | 5/1/2010 12:00:00 AM |
| 修稿时间： | 2010/6/25 0:00:00 |
Forming process of the high pressure metamorphic belt in central Qiangtang, Tibet |
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| DONG YongSheng,LI Cai,SHI JianRong,ZHANG XiuZheng and WANG ShengYun.Forming process of the high pressure metamorphic belt in central Qiangtang, Tibet[J].Acta Petrologica Sinica,2010,26(7):2099-2105. |
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| Authors: | DONG YongSheng LI Cai SHI JianRong ZHANG XiuZheng and WANG ShengYun |
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| Institution: | College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China;College of Earth Sciences, Jilin University, Changchun 130061, China |
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| Abstract: | The Longmu Co-Shuanghu-Lancang tectonic melange belt is composed of Late Paleozoic epirock, ophiolite melange, and the high pressure metamorphic belt in central Qiangtang consisting of eclogite, glaucophane schist and garnet-muscovite schist. It is the product of Paleo-Tethys Ocean subduction and later tectonism. Though the research on the field geological features, petrology, mineralogy and isotope chronology of different rock types, we attribute that eclogite and garnet-muscovite schist experienced a different formation process in early stage. The high pressure metamorphic belt constituted by eclogite and garnet-muscovite schist was ultimately formed by the tectonic movement of eclogite exhumation, which is a period blueschist facies metamorphism and deformation, leading to retrograde metamorphism of the eclogite and the formation of glaucophane schist. Results of isotope geochronology study suggest that eclogite facies metamorphism occurred at around 240Ma and its retrograde metamorphism of glaucophane schist facies at 220~200Ma. The high pressure metamorphic belt is ultimately uplifted and exposed to surface before 214Ma. |
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| Keywords: | High pressure metamorphic belt Eclogite facies Glaucophane schist facies Tectonic emplacement Central Qiangtang |
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