An (in-)coherent metamorphic evolution of high-P eclogites and their host rocks in the Chinese southwest Tianshan?
文献类型：期刊论文
| 作者 | Meyer, M.1; Klemd, R.1; John, T.2; Gao, J.3; Menneken, M.2 |
| 刊名 | JOURNAL OF METAMORPHIC GEOLOGY
 |
| 出版日期 | 2016-02-01 |
| 卷号 | 34期号:2页码:121-146 |
| 关键词 | (U)HP metamorphism eclogite P-T path thermobarometry Tianshan |
| DOI | 10.1111/jmg.12175 |
| 文献子类 | Review |
| 英文摘要 | In the (ultra-)high-P-low-T metamorphic terrane of the Chinese South Tianshan, discontinuous mafic blocks and boudins (former upper oceanic crust) are now embedded in voluminous (mainly metasedimentary) host rocks. Two different models were proposed and relate the occurrence of both high-P and ultra-high-P mafic and metasedimentary rocks to either (i) a tectonic melange style exhumation, with no exhumation of coherent units, but different lithologies derived from different depths juxtaposed and intermingled during exhumation in the subduction channel, or (ii) the evolution of two coherent metamorphic belts: one with high-P and the other with ultra-high-P conditions. In contrast to most previous studies in the Chinese South Tianshan which focused either on single eclogites or metasedimentary rocks (assumed as representative), this study concentrates on the systematic investigation of both mafic boudins and their immediate sedimentary host rocks, because the investigation of both lithologies and the comparison of their metamorphic evolution is crucial to reconstruct the geodynamical context of the whole (ultra-)high-P-low-T metamorphic complex. Several sample pairs consisting of both lithologies were geochemically investigated and their respective metamorphic evolution was reconstructed using geothermobarometry and thermodynamic modelling. The latter approach considers changes in the mineral assemblage during the metamorphic evolution, as well as changes in mineral composition, which may help to determine the metamorphic history of a rock despite the preservation of critical mineral assemblages. All samples experienced a clockwise P-T path with overall maximum P-T conditions of 540-550 degrees C and 1.9-2.25GPa for the host rocks, and 555-575 degrees C and 2.2-2.5GPa for the eclogites. Peak-metamorphic temperatures of similar to 525-540 degrees C of the metasedimentary host rocks were also confirmed by Raman spectroscopy of carbonaceous material. Results from thermobarometry and thermodynamic modelling are consistent with the observation that none of the samples contains mineral relicts indicating UHP conditions (like coesite in garnet) and neither conventional thermobarometry, nor thermodynamical modelling resulted in P-T conditions in the stability field of coesite. Thus, no evidence of ultra-high-P conditions was found. Given that the whole sampled river valley lies within the proposed ultra-high-P sub-belt' and considering former studies, which showed that at other places within this unit' both ultra-high-P and high-P rocks are now juxtaposed on a small scale, the formation of the whole (ultra-)high-P-low-T metamorphic belt in the Chinese South Tianshan as a tectonic melange style exhumation is more convincing than the formation and juxtaposition of two coherent metamorphic units with high-P and ultra-high-P conditions respectively. |
| WOS关键词 | ASIAN OROGENIC BELT ; CALCULATED PHASE-EQUILIBRIA ; TRACE-ELEMENT MOBILIZATION ; CONVERGENT PLATE MARGINS ; COESITE-BEARING ECLOGITE ; SUBDUCTION-CHANNEL MODEL ; HP-LT ROCKS ; NW-CHINA ; WESTERN TIANSHAN ; HIGH-PRESSURE |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000369864800002 |
| 资助机构 | Deutsche Forschungsgemeinschaft(KL692/17-3) ; Deutsche Forschungsgemeinschaft(KL692/17-3) ; National Natural Science Foundation of China(41025008) ; National Natural Science Foundation of China(41025008) ; IGCP Project(592) ; IGCP Project(592) ; Deutsche Forschungsgemeinschaft(KL692/17-3) ; Deutsche Forschungsgemeinschaft(KL692/17-3) ; National Natural Science Foundation of China(41025008) ; National Natural Science Foundation of China(41025008) ; IGCP Project(592) ; IGCP Project(592) |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/62050]  |
| 专题 | 地质与地球物理研究所_中国科学院矿产资源研究重点实验室 |
| 作者单位 | 1.Univ Erlangen Nurnberg, GeoZentrum Nordbayern, Schlossgarten 5a, D-91054 Erlangen, Germany 2.Free Univ Berlin, Inst Geol Wissensch, Malteserstr 74-100, D-12449 Berlin, Germany 3.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Mineral Resources, POB 9825, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Meyer, M.,Klemd, R.,John, T.,et al. An (in-)coherent metamorphic evolution of high-P eclogites and their host rocks in the Chinese southwest Tianshan?[J]. JOURNAL OF METAMORPHIC GEOLOGY,2016,34(2):121-146. |
| APA | Meyer, M.,Klemd, R.,John, T.,Gao, J.,&Menneken, M..(2016).An (in-)coherent metamorphic evolution of high-P eclogites and their host rocks in the Chinese southwest Tianshan?.JOURNAL OF METAMORPHIC GEOLOGY,34(2),121-146. |
| MLA | Meyer, M.,et al."An (in-)coherent metamorphic evolution of high-P eclogites and their host rocks in the Chinese southwest Tianshan?".JOURNAL OF METAMORPHIC GEOLOGY 34.2(2016):121-146. |
入库方式： OAI收割
来源：地质与地球物理研究所
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