Geochemical and Sr-Nd isotopic characteristics of Cretaceous to Paleocene granitoids and volcanic rocks, SE Tibet: Petrogenesis and tectonic implications
文献类型：期刊论文
| 作者 | Lin, I-Jhen1; Chung, Sun-Lin1; Chu, Chiu-Hong1; Lee, Hao-Yang1; Gallet, Sylvain1; Wu, Genyao2; Ji, Jianqing3; Zhang, Yuquan4 |
| 刊名 | JOURNAL OF ASIAN EARTH SCIENCES
 |
| 出版日期 | 2012-07-07 |
| 卷号 | 53页码:131-150 |
| 关键词 | Tibet Tethyan subduction Granitoids Geochemistry Sr-Nd isotopes |
| ISSN号 | 1367-9120 |
| DOI | 10.1016/j.jseaes.2012.03.010 |
| 文献子类 | Article |
| 英文摘要 | Northward subduction of the Neo-Tethyan oceanic lithosphere beneath South Asia gave rise to an Andean-type convergent margin with arc magmatism starting since at least the early Jurassic and lasting until the Eocene. This study reports geochemical and Sr-Nd isotope data of the early Cretaceous (similar to 133-110 Ma) to Paleocene (similar to 60 Ma) magmatic. belt that formed in the eastern Lhasa terrane, SE Tibet, including three major Transhimalayan batholiths, namely, Azhagong. Demulha, and Chayu, and an early Cretaceous volcanic succession from Ranwu area. All these rocks show relative enrichments in LILE and LREE, and depletions in HFSE, corresponding to the geochemical characteristics of arc magmas from modern subduction zones. While the Azhagong batholith consists typically of metaluminous I-type granitoids that occasionally contain mafic enclaves, highly fractionated, peraluminous S-type and A-type granites are observed from the Chayu and Demulha batholiths, respectively. These granitoids, as a whole, show heterogeneous Sr and Nd isotope ratios, with epsilon(Nd)(T) varying from -1.5 to -13 and I-Sr from 0.703 to 0.745. The Ranwu volcanic rocks, which range from basaltic to dacitic compositions, are calc-alkaline in nature. They have epsilon(Nd)(T) from +3 to -6 and I-Sr from 0.705 to 0.707, overlapping the isotopic range of the Azhagong mafic enclaves. The overall geochemical and Sr-Nd isotope data suggest three magma source components involved in the petrogenesis, which are the mantle wedge, and the lower and upper parts of the Lhasa continental crust. Accordingly, we propose a two-stage petrogenetic model involving (1) deep level differentiation of the mantle wedge-derived mafic magmas associated with assimilation by the lower continental crust of the Lhasa terrane and (2) additional differentiation and upper crustal contamination of the evolved magmas as they rise and install in shallow-level magma chambers. While the first stage can explain how the Ranwu volcanics and Azhagong enclaves formed, the second accounts for the emplacement of the Azhagong and Chayu batholiths. The shallow intrusions, moreover, may have caused low-pressure melting of existing calc-alkaline rocks of Paleoproterozoic Nd isotope model age to produce the early Cretaceous (similar to 125 Ma) A-type granites in the Demulha batholith, a specific rock type that occurs rarely in subduction zones but echoes with the notion for an extension setting in the region. This setting may have taken place after the late Jurassic-early Cretaceous continental collision between the Lhasa and Qiangtang terranes, and interacted with the back-arc evolution in the Neo-Tethyan subduction system. (C) 2012 Elsevier Ltd. All rights reserved. |
| WOS关键词 | A-TYPE GRANITES ; ZIRCON U-PB ; SOUTHERN TIBET ; GANGDESE BATHOLITH ; HF ISOTOPES ; POSTCOLLISIONAL MAGMATISM ; SOUTHEASTERN TIBET ; EASTERN GANGDESE ; CENTRAL ANDES ; I-TYPE |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000306246700012 |
| 出版者 | PERGAMON-ELSEVIER SCIENCE LTD |
| 资助机构 | National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC ; National Science Council, Taiwan, ROC |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/84220]  |
| 专题 | 中国科学院地质与地球物理研究所 |
| 通讯作者 | Chung, Sun-Lin |
| 作者单位 | 1.Natl Taiwan Univ, Dept Geosci, Taipei 10617, Taiwan 2.Chinese Acad Sci, Inst Geol & Geophys, Beijing, Peoples R China 3.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China 4.Chinese Acad Sci, Guangzhou Inst Geochem, Guangzhou, Guangdong, Peoples R China |
| 推荐引用方式 GB/T 7714 | Lin, I-Jhen,Chung, Sun-Lin,Chu, Chiu-Hong,et al. Geochemical and Sr-Nd isotopic characteristics of Cretaceous to Paleocene granitoids and volcanic rocks, SE Tibet: Petrogenesis and tectonic implications[J]. JOURNAL OF ASIAN EARTH SCIENCES,2012,53:131-150. |
| APA | Lin, I-Jhen.,Chung, Sun-Lin.,Chu, Chiu-Hong.,Lee, Hao-Yang.,Gallet, Sylvain.,...&Zhang, Yuquan.(2012).Geochemical and Sr-Nd isotopic characteristics of Cretaceous to Paleocene granitoids and volcanic rocks, SE Tibet: Petrogenesis and tectonic implications.JOURNAL OF ASIAN EARTH SCIENCES,53,131-150. |
| MLA | Lin, I-Jhen,et al."Geochemical and Sr-Nd isotopic characteristics of Cretaceous to Paleocene granitoids and volcanic rocks, SE Tibet: Petrogenesis and tectonic implications".JOURNAL OF ASIAN EARTH SCIENCES 53(2012):131-150. |
入库方式： OAI收割
来源：地质与地球物理研究所
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