Variation in peak P-T conditions across the upper contact of the UHP terrane, Dabieshan, China: gradational or abrupt?
文献类型：期刊论文
| 作者 | Shi, Y.; Wang, Q. |
| 刊名 | JOURNAL OF METAMORPHIC GEOLOGY
 |
| 出版日期 | 2006-12-01 |
| 卷号 | 24期号:9页码:803-822 |
| 关键词 | Dabieshan eclogites peak P-T conditions Taihu area |
| ISSN号 | 0263-4929 |
| DOI | 10.1111/j.1525-1314.2006.00670.x |
| 文献子类 | Article |
| 英文摘要 | The Southern Dabieshan Terrane (SDT) has previously been divided into high-pressure (HP) and ultrahigh-pressure (UHP) terranes, and its regional extent and the tectonic nature of its boundaries are hotly debated topics. In this study, an eclogite-bearing area of 100 km(2) near Taihu is mapped in detail, and divided into Northern, Middle and Southern Zones on the basis of lithological characteristics. The Northern Zone consists of epidote-biotite gneiss and eclogite blocks, the Middle Zone includes granitic gneiss, biotite gneiss, eclogites and amphibolite, and the Southern Zone is composed mainly of garnet-bearing mica schist. The eclogites occur mainly as lens or blocks in the Northern and Middle Zones. The peak P-T conditions for 61 eclogite samples across the area are estimated using the Grt-Cpx Fe2+-Mg thermometers and the Grt-Cpx-Phe barometers. The results indicate three different P-T regions: 2.82-4.09 GPa/759-942 degrees C in the Northern Zone, and 2.00-3.54 GPa/641-839 degrees C in the granitic gneiss and 1.38-2.36 GPa/535-768 degrees C in the biotite gneiss from the Middle Zone. Combined with the spatial distribution of eclogites across the area, the P-T values for eclogites increase continuously from the south to the north, defining a reference 'geotherm' of 5 degrees C km(-1). However, some unreasonable apparent gradients can be established along two south-north profiles across the area, and display a P-T difference between the Northern and Middle zones. On the basis of the average P-T data for eclogites across the area, a gap of at least 0.3 GPa/20 degrees C exists between the Northern and Middle zones. By contrast, the P-T values of eclogites from the Middle zone show a coherent pattern with transitional characteristics from HP in the south to UHP in the north. We suggest that the SDT was a coherent slab during subduction, and was broken up by a major fault during exhumation, which was formed under UHP metamorphic conditions. |
| WOS关键词 | COESITE-BEARING ECLOGITES ; PRESSURE METAMORPHIC BELT ; EAST-CENTRAL CHINA ; COOLING HISTORY ; MOUNTAINS ; SHAN ; ZIRCON ; GEOTHERMOMETER ; CONSTRAINTS ; EXHUMATION |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000242017000002 |
| 出版者 | BLACKWELL PUBLISHING |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/66420]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Shi, Y. |
| 作者单位 | Chinese Acad Sci, Inst Geol & Geophys, State Key Lab Lithospher Evolut, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Shi, Y.,Wang, Q.. Variation in peak P-T conditions across the upper contact of the UHP terrane, Dabieshan, China: gradational or abrupt?[J]. JOURNAL OF METAMORPHIC GEOLOGY,2006,24(9):803-822. |
| APA | Shi, Y.,&Wang, Q..(2006).Variation in peak P-T conditions across the upper contact of the UHP terrane, Dabieshan, China: gradational or abrupt?.JOURNAL OF METAMORPHIC GEOLOGY,24(9),803-822. |
| MLA | Shi, Y.,et al."Variation in peak P-T conditions across the upper contact of the UHP terrane, Dabieshan, China: gradational or abrupt?".JOURNAL OF METAMORPHIC GEOLOGY 24.9(2006):803-822. |
入库方式： OAI收割
来源：地质与地球物理研究所
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