| 赣北大湖塘平苗矿段白云母花岗岩锆石U-Pb年代学、地球化学及地质意义 |
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| 引用本文： | 余振东,项新葵,谭荣,孙德明,张斯. 赣北大湖塘平苗矿段白云母花岗岩锆石U-Pb年代学、地球化学及地质意义[J]. 吉林大学学报(地球科学版), 2020, 50(5): 1505-1517. DOI: 10.13278/j.cnki.jjuese.20190297 |
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| 作者姓名： | 余振东 项新葵 谭荣 孙德明 张斯 |
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| 作者单位： | 江西省地质矿产勘查开发局九一六大队, 江西 九江 332100 |
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| 基金项目： | 中国地质调查局项目（121201004000150017-13） |
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| 摘 要： | 赣北大湖塘钨铜多金属矿集区位于扬子板块东南缘、江南造山带中段，是近年来查明的世界级钨矿产地之一。对大湖塘平苗矿段中粗粒白云母花岗岩进行了岩相学、锆石U-Pb年代学、地球化学及成矿作用的研究，结果表明，此花岗岩内白云母显示原生白云母的特性，LA-ICP-MS锆石U-Pb年龄为（145.7±0.6）Ma，与区内细粒黑云母花岗岩测试年龄相近，系同源岩浆演化结晶分异的结果，为燕山期多期次岩浆侵入的第二阶段。燕山期岩石单元先后有似斑状黑（二）云母花岗岩→细粒黑云母花岗岩、白云母花岗岩→花岗斑岩，白云母花岗岩是区内重要的成矿地质体之一。地球化学研究表明，该白云母花岗岩为高分异S型花岗岩，具有高硅（w（SiO2）=73.14%~74.19%）、富碱、过铝质的特征及较高的分异指数，轻重稀土分馏明显，呈左高右低的深V型，Eu表现为强烈的亏损，存在REE四分组效应，Rb/Sr、Rb/Ba的平均值分别为151.81和245.21，表明岩浆是经历多阶段分离结晶、高度分异的结果。
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| 关 键 词： | 大湖塘 白云母花岗岩 锆石U-Pb年代学 地球化学 |
| 收稿时间： | 2019-12-22 |
Zircon U-Pb Chronology,Geochemistry and Geological Significance of Coarse Muscovite Granite in Pingmiao Mining Area of Dahutang,North Jiangxi |
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| Yu Zhendong,Xiang Xinkui,Tan Rong,Sun Deming,Zhang Si. Zircon U-Pb Chronology,Geochemistry and Geological Significance of Coarse Muscovite Granite in Pingmiao Mining Area of Dahutang,North Jiangxi[J]. Journal of Jilin Unviersity:Earth Science Edition, 2020, 50(5): 1505-1517. DOI: 10.13278/j.cnki.jjuese.20190297 |
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| Authors: | Yu Zhendong Xiang Xinkui Tan Rong Sun Deming Zhang Si |
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| Affiliation: | No. 916 Geological Party, Jiangxi Bureau of Geology&Mineral Exploration, Jiujiang 332100, Jiangxi, China |
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| Abstract: | Dahutang tungsten-copper polymetallic ore concentration area in north Jiangxi is located in the southeastern margin of Yangtze plate and the middle part of Jiangnan orogenic belt, which is one of the world-class tungsten deposits discovered in recent years. In this research, the petrographic, zircon U-Pb chronology, geochemistry and mineralization of coarse muscovite granites in Pingmiao ore of Dahutang were studied. The results show that the muscovite in the granites is a primary muscovite, and the zircon U-Pb age of LA-ICP-MS is (145.7±0.6)Ma, closed to the test age of fine biotite granite in this area, which is the result of crystallization differentiation of homologous magma evolution, and the magmatic intrusion of the second stage of the Yanshanian multiple stages. The Yanshanian rock units are porphyritic-like biotite (muscovite) granite →biotite granite, muscovite granite→granite porphyry;of them, the muscovite granite is one of the important metallogenic geological bodies in this area. The geochemical study shows that the muscovite granite is highly differentiated S-type granite, with high SiO2=73.14%-74.19%, rich-alkali, per-aluminous characteristics,and high differentiation index. The fractionation of light and heavy rare earth is obvious, in deep V-shaped with high left and low right, strong loss of Eu, and REE quadruple grouping effect. The average values of Rb/Sr and Rb/Ba are 151.81 and 245.21 respectively, indicating that the magma is the result of multi-stage crystallization and high differentiation. |
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| Keywords: | Dahutang muscovite granite zircon U-Pb chronology geochemistry |
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