Formation of HP-LT rocks and their tectonic implications in the western Tianshan Orogen, NW China: geochemical and age constraints
文献类型：期刊论文
| 作者 | Gao, J; Klemd, R |
| 刊名 | LITHOS
 |
| 出版日期 | 2003 |
| 卷号 | 66期号:1-2页码:1-22 |
| 关键词 | HP-LT rocks chemical composition Sm-Nd isochron Ar-40/Ar-39 plateau age Tianshan |
| ISSN号 | 0024-4937 |
| 文献子类 | Article |
| 英文摘要 | The Western Tianshan high-pressure/low-temperature metamorphic belt in northwestern China formed within a Paleozoic accretionary wedge on the south side of the Yili-Central Tianshan plate. It comprises various lithologies, including mafic metavolcanic rocks, metavolcaniclastic rocks, metagreywacke, marble and serpentinite. The metavolcanics comprise eclogite, omphacitite, epidosite and blueschist. The trace and rare-earth element characteristics of these rocks indicate MORB to OIB affinities suggesting a seamount-like setting for the protoliths of these rocks. The epsilon(Nd) value of the eclogite (+8.9) indicates that the protolith was derived from a long-term depleted mantle, i.e. an N-MORB source, supporting the trace and rare-earth element characteristics of these samples. Sm-Nd isochron dating of 343 +/- 44 Ma (Omp-Gln-Grt-WR) and an age of 346 +/- 3 Ma (Grt-Gln) were determined using an eclogite boudin within blueschist. A well-defined Ar-40/Ar-39 plateau age of 344 +/- 1 Ma was obtained for crossite from an omphacite-phengite-bearing blueschist and is concordant with the Sm-Nd isochron age for the eclogite, suggesting that neither argon loss nor excess argon affected the crossite. A well-defined Ar-40/Ar-39 plateau age of 331 +/- 2 Ma was determined for phengite from the same sample. The high-pressure metamorphic rocks were formed by the B-type subduction of a Paleozoic 'South Tianshan Ocean' about 344 Ma ago. They were, however, exhumed to higher crustal levels during the collision of the Tarim and Yili-Central Tianshan plates about 331 Ma ago, similar to an 'Alpine-type' tectonic regime. (C) 2002 Elsevier Science B.V All rights reserved. |
| WOS关键词 | HIGH-PRESSURE METAMORPHISM ; ECLOGITE-FACIES ROCKS ; NORTHWESTERN CHINA ; EXCESS ARGON ; RB-SR ; SOUTH TIANSHAN ; OCEANIC-CRUST ; CENTRAL-ASIA ; TIEN-SHAN ; SM-ND |
| WOS研究方向 | Geochemistry & Geophysics ; Mineralogy |
| 语种 | 英语 |
| WOS记录号 | WOS:000180902400001 |
| 出版者 | ELSEVIER SCIENCE BV |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/78359]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Gao, J |
| 作者单位 | 1.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, Beijing 100029, Peoples R China 2.Univ Wurzburg, Mineralog Inst, D-97074 Wurzburg, Germany |
| 推荐引用方式 GB/T 7714 | Gao, J,Klemd, R. Formation of HP-LT rocks and their tectonic implications in the western Tianshan Orogen, NW China: geochemical and age constraints[J]. LITHOS,2003,66(1-2):1-22. |
| APA | Gao, J,&Klemd, R.(2003).Formation of HP-LT rocks and their tectonic implications in the western Tianshan Orogen, NW China: geochemical and age constraints.LITHOS,66(1-2),1-22. |
| MLA | Gao, J,et al."Formation of HP-LT rocks and their tectonic implications in the western Tianshan Orogen, NW China: geochemical and age constraints".LITHOS 66.1-2(2003):1-22. |
入库方式： OAI收割
来源：地质与地球物理研究所
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