Nb/Ta variations in Archean TTG: Implications for "Na-Ta paradox"
文献类型：期刊论文
| 作者 | Wang Dan2; Guo JingHui3,4; Ma XuDong1 |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2021-02-01 |
| 卷号 | 37期号:2页码:341-355 |
| 关键词 | Archean TTG Lower crust Nb/Ta ratio |
| ISSN号 | 1000-0569 |
| DOI | 10.18654/1000-0569/2021.02.02 |
| 英文摘要 | The Archean continental crust predominantly consists of Tonalite-Trondhjemite-Granodiorite (TTG) associations. Nb/Ta variations in TTG are not only related to their petrogenesis, but also associated with Archean crustal differentiation and tectonics on early Earth. In this study, we provide detailed the whole-rock (WR) major and trace elements, and trace element analysis of biotite and amphibole in both TTG and mafic enclaves from the Yinshan Block. Amphiboles from the granodiorite and co-genetic mafic enclave have similar Mg-# values but clearly different Nb/Ta ratios. Higher Nb/Ta ratios are in the amphiboles from the granodiorites than those from the mafic enclaves (38 similar to 70 vs. 30 similar to 50). Amphiboles in the mafic enclaves have higher Ta and Cr contents but lower Nb/Ta ratios, in comparison with those from the host granodiorite. Nb/Ta ratios in amphibole decrease with the increasing of Cr contents. The WR geochemical data show that TTGs from the Yinshan Block have high Nb/Ta ratios of 13 similar to 65 (ay. 31), and the mafic enclaves have variable Nb/Ta ratios of 10 similar to 56. As the average Nb/Ta ratio of the basalts from the Archean greenstone belt is about 15, variable Nb/Ta ratios of amphibolite and mafic granulite from the Yinshan Block reflect that they must have experienced partial melting or later metasomatism in the lower crust. Partial melting of high Nb/Ta amphibolites and granulites may produce high Nb/Ta TTG melts, as the melts would inherit high Nb/Ta ratios from their source. Therefore, we suggested that high Nb/Ta TTG is not necessarily formed through high-pressure eclogite-facies partial melting of the hydrous oceanic crust in the subduction zone. Partial melting of the biotite/ amphibole-rich residues is one of the crucial mechanisms for producing high Nb/Ta TTG. |
| WOS关键词 | NORTH CHINA CRATON ; TRONDHJEMITE-GRANODIORITE TTG ; EARLY CONTINENTAL-CRUST ; XI ULANBULANG AREA ; YINSHAN BLOCK ; METAMORPHIC ROCKS ; TRACE-ELEMENTS ; FRACTIONATION ; CONSTRAINTS ; EVOLUTION |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000629649100002 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/101039]  |
| 专题 | 地质与地球物理研究所_岩石圈演化国家重点实验室 |
| 通讯作者 | Wang Dan |
| 作者单位 | 1.Chinese Acad Geol Sci, Inst Mineral Resources, MNR Key Lab Metallogeny & Mineral Resource Assess, Beijing 100037, Peoples R China 2.Chinese Acad Geol Sci, Inst Geol, Key Lab Deep Earth Dynam, Minist Nat Resources, Beijing 100037, Peoples R China 3.Univ Chinese Acad Sci, Coll Earth & Planetary Sci, Beijing 100049, Peoples R China 4.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 | Wang Dan,Guo JingHui,Ma XuDong. Nb/Ta variations in Archean TTG: Implications for "Na-Ta paradox"[J]. ACTA PETROLOGICA SINICA,2021,37(2):341-355. |
| APA | Wang Dan,Guo JingHui,&Ma XuDong.(2021).Nb/Ta variations in Archean TTG: Implications for "Na-Ta paradox".ACTA PETROLOGICA SINICA,37(2),341-355. |
| MLA | Wang Dan,et al."Nb/Ta variations in Archean TTG: Implications for "Na-Ta paradox"".ACTA PETROLOGICA SINICA 37.2(2021):341-355. |
入库方式： OAI收割
来源：地质与地球物理研究所
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