| 广西米场花岗岩及其暗色微粒包体的地球化学特征和成因分析 |
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| 关键词:dark microgranular enclave magmatic mixing geochemistry Yunkai uplift Guangxi |
| 基金项目:广西壮族自治区地质矿产勘查开发局“广西陆川县米场钨钼矿床控矿因素、富集规律与成因机制研究”(编号: 地勘【2006】); 中国地质调查局项目(编号: 200811008) |
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| Geochemistry and Genesis of Michang Granites and Their Dark Microgranular Enclaves in Guangxi |
| The biotite granite on the southwestern margin of Bobai-Cenxi faulted zone contains abundant mafic magmatic enclaves. The pluton exhibits excellent evidence for magma mixing and mingling, such as the K-feldspar megacrysts in the mafic magmatic enclaves (MME), augen quartz with dark edging, long prisms of apatite, and plagioclase with inner zone. The authors systematically studied petrological and geochemical characteristics of the pluton and the enclaves, and have concluded that the Michang pluton and the enclaves belong to meta-aluminous, high-K calc-alkaline rocks. The selected major oxides of MME and biotite granite show a linear correlation in Harker diagrams, and trace elements studies show that they are rich in both large ion lithophile elements and high field strength elements. The Nb/Ta ratio varies from 11.51 to 13.34, suggesting that the grantie probably experienced strong magma mixing. The similar REE pattern for MME and biotite granite gives an image of magma mixing; the crystallization temperature and pressure of enclaves and host granite are very close to each other, in the range of 595～697℃ and 3.64～4.61kbar respectively. According to a comprehensive analysis of their tectonic settings as well as petrographical characteristics and geochemical data, it is suggested that the dark microgranular enclaves in Michang pluton were generated by mixing of underplating basic magma and its induced crustal felsic magma in an extension environment. |
| FU Qiang,GE Wen-sheng,WEN Chang-shun,CAI Ke-qin,LI Shi-fu,ZHANG Zhi-wei,LI Xiao-fei.2011.Geochemistry and Genesis of Michang Granites and Their Dark Microgranular Enclaves in Guangxi[J].Acta Geoscientica Sinica,32(3):293-303. |
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