Magma mixing identified in the Guokeshan pluton, northern margin of the Qaidam basin : Evidences from petrography, mineral chemistry, and whole-rock geochemistry
文献类型：期刊论文
| 作者 | Niu ManLan1; Zhao QiQi1; Wu Qi1; Li XiuCai1; Yan Zhen2; Li JiLiang3; Sun Yi1; Yuan XiaoYu1 |
| 刊名 | ACTA PETROLOGICA SINICA
 |
| 出版日期 | 2018 |
| 卷号 | 34期号:7页码:1991-2016 |
| 关键词 | Mafic microgranular enclave Early-middle Triassic Complex plagioclase zoning Magma mingling Guokeshan pluton Northern margin of the Qaidam basin |
| ISSN号 | 1000-0569 |
| 英文摘要 | The Qinghai Nanshan magmatic belt, located along the northern margin of the Qaidam basin (NQB) and West Qinling Orogen, is mainly composed of Late Permian to Triassic granites that are genetically linked to subduction and collision of the Paleo-Tethys ocean. To constrain their origins and provide new insights on the curst-mantle interaction, an integration of methods including pertrology, mineralogy, geochemistry and Sr-Nd isotopes is performed on the mafic microgranular enclaves (MMEs) and their host quartz diorites from the Guokeshan pluton in the eastern segment of the NQB. Zircon LA-ICP-MS dating reveals that the Guokeshan quartz-diorites are coeval with their MMEs (similar to 247Ma). The quartz diorites are medium-K calc-alkaline I-type granites that exhibit moderate potassium (K2O = 1.43% similar to 2.18% ) and high Mg-# (48.9 similar to 52.4). They are also characterized by arc-type enrichment of LREEs and LLIEs ( e.g. , U, K, Pb), depletion of HREEs and HFSEs (e.g. , Nb, Ta, Ti) and weakly Eu depletions (Eu/Eu* = 0.71 similar to 0.85). Their evolved Sr-Nd isotopic compositions, coupled with disequilibrium textures of oscillatory-zoned plagioclases, spike zone in plagioclase and biotite enclosed within amphibole, indicate precursor magmas were mainly produced by partial melting of mafic lower crust with additional input of a mafic component derived from an enriched mantle. In contrast, the MMEs possess lower SiO2 (56.68% similar to 59.28% ) , and higher epsilon(Nd)(t) and Mg-# values(58.5 similar to 62.2), and flatter REE distribution patterns. In combination with field and petrological observations, such as chilled margins, spheroidal shapes, acicular apatite, reverse-zoned plagioclase, blade-shaped amphibole in plagioclase, the MMEs and host granitoids were inferred as products by different percentage mixing of subduction-related metasomatized mantle-derived mafic and ancient (Late-Paleoproterozoic ) crust-derived felsic magmas. In association with previous sedimentological research and tectonic analysis, in this paper, we propose that the Early-Middle Triassic magmatism in the Qinghai Nanshan magmatic belt might be related to underplating of mantle-derived magma and magma mixing induced by the northernward subduction of the Paleo-Tethys ocean. |
| WOS关键词 | ZIRCON U-PB ; TRACE-ELEMENT COMPOSITION ; SOURCE MATERIAL RESTITE ; QINGHAI-TIBET PLATEAU ; WEST QINLING TERRANE ; LACHLAN FOLD BELT ; MICROGRANULAR ENCLAVES ; CALC-ALKALINE ; NORTHEASTERN MARGIN ; QUANJI MASSIF |
| WOS研究方向 | Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000451724300011 |
| 出版者 | SCIENCE PRESS |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/89630]  |
| 专题 | 地质与地球物理研究所_离退休科研人员 |
| 通讯作者 | Niu ManLan |
| 作者单位 | 1.Hefei Univ Technol, Sch Resources & Environm Engn, Hefei 230009, Anhui, Peoples R China 2.Chinese Acad Geol Sci, Inst Geol, Beijing 100037, Peoples R China 3.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China |
| 推荐引用方式 GB/T 7714 | Niu ManLan,Zhao QiQi,Wu Qi,et al. Magma mixing identified in the Guokeshan pluton, northern margin of the Qaidam basin : Evidences from petrography, mineral chemistry, and whole-rock geochemistry[J]. ACTA PETROLOGICA SINICA,2018,34(7):1991-2016. |
| APA | Niu ManLan.,Zhao QiQi.,Wu Qi.,Li XiuCai.,Yan Zhen.,...&Yuan XiaoYu.(2018).Magma mixing identified in the Guokeshan pluton, northern margin of the Qaidam basin : Evidences from petrography, mineral chemistry, and whole-rock geochemistry.ACTA PETROLOGICA SINICA,34(7),1991-2016. |
| MLA | Niu ManLan,et al."Magma mixing identified in the Guokeshan pluton, northern margin of the Qaidam basin : Evidences from petrography, mineral chemistry, and whole-rock geochemistry".ACTA PETROLOGICA SINICA 34.7(2018):1991-2016. |
入库方式： OAI收割
来源：地质与地球物理研究所
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