| 小秦岭华山和文峪岩体成金潜力异同分析:来自锆石群形态标型的证据 |
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| 引用本文： | 温子豪,李胜荣,袁茂文,智泽亚,李士胜. 小秦岭华山和文峪岩体成金潜力异同分析:来自锆石群形态标型的证据[J]. 延边大学学报(自然科学版), 2018, 0(5): 535-545 |
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| 作者姓名： | 温子豪 李胜荣 袁茂文 智泽亚 李士胜 |
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| 作者单位： | 1.中国地质大学(北京)地球科学与资源学院，北京 100083；2.中国地质大学(北京)地质过程与矿产资源国家重点实验室，北京 100083 |
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| 摘 要： | 小秦岭金矿集中区的华山和文峪岩体均是与金矿有密切成因联系的花岗岩。目前在文峪岩体周边发现的金矿床数量明显比华山岩体周边多。明确华山和文峪岩体的成矿潜力异同对在华山岩体周边找矿具有重要意义。在岩相学研究基础上，主要运用Pupin提出的锆石群形态温度指数-碱度指数图解，对采自华山岩体中间相粗粒黑云二长花岗岩、边缘相中细粒黑云二长花岗岩及文峪岩体中间相粗粒黑云二长花岗岩样品进行镜下观察，并对挑选出的锆石群进行形态分类、统计和对比分析。据野外观察，文峪岩体的暗色微晶包体较华山岩体中相对较多。两个岩体中部的锆石结晶较晚，粒度集中在60~240 μm,边部的锆石结晶较早，粒度多在30~100 μm。锆石标型群演化势(TET)曲线显示岩浆向低温富碱方向演化。华山岩体边缘相中细粒黑云二长花岗岩的锆石标型群演化势曲线较短，显示锆石整体结晶环境温度较高；两个岩体中间相粗粒黑云二长花岗岩岩浆均形成于混合源区，显示经历了较长时间的冷却过程，也更富碱。这些现象暗示形成华山岩体的岩浆经历了与形成文峪岩体的岩浆相似的起源和演化过程，即在地壳深部形成花岗岩浆的同时发生幔源岩浆混合生成混源岩浆。因此，华山岩体应当具有与文峪岩体相似的成金潜力，应加强在华山岩体周围的金矿找矿工作。
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| 关 键 词： | 金矿 黑云二长花岗岩 锆石形态标型 暗色微晶包体 标型群演化势 混合源区 成矿潜力 小秦岭 |
Analysis of Similarities and Differences of Gold Potential Between Huashan and Wenyu Plutons in Xiaoqinling,China: Evidence from Morphological Characteristics of Zircons |
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| WEN Zi-hao,LI Sheng-rong,YUAN Mao-wen,ZHI Ze-ya,LI Shi-sheng. Analysis of Similarities and Differences of Gold Potential Between Huashan and Wenyu Plutons in Xiaoqinling,China: Evidence from Morphological Characteristics of Zircons[J]. Journal of Yanbian University (Natural Science), 2018, 0(5): 535-545 |
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| Authors: | WEN Zi-hao LI Sheng-rong YUAN Mao-wen ZHI Ze-ya LI Shi-sheng |
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| Affiliation: | 1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;2. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China |
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| Abstract: | The Huashan and Wenyu plutons in the Xiaoqinling gold province are both granite bodies closely related to the existence of gold deposit. At present, most of the gold deposits are located around the Wenyu pluton and with only a few around the Huashan pluton. To ascertain the similarities and differences of metallogenic potential of Huashan and Wenyu plutons is of great significance for prospecting deposits around the Huashan pluton. On the basis of petrographic studies, the coarse-grained biotite monzonitic granites from the middle of the Huashan and Wenyu plutons, and the medium fine-grained biotite monzonitic granites from the edge of the Huashan pluton were examined by Pupin’s method of zircon morphotypes. They were observed under microscope, and the selected zircons were morphologically classified, statistically analyzed and compared. According to field observations, the mafic microgranular enclaves in the Wenyu pluton were relatively more abundant than the Huashan pluton. Zircons in the middle of the Huashan and Wenyu plutons were crystallized during the late period, and their grain sizes were concentrated in the range of 60 to 240 μm. While zircons at the edge were crystallized earlier and had a grain size of 30 to 100 μm. The typological evolution trend(TET) curve shows that the magma evolved toward lower temperature and richer alkali direction. The zircon TET curve of the medium fine-grained biotite monzonitic granite from the edge of Huashan pluton is shorter, indicating that the overall crystallization temperature of the zircons was higher. The coarse-grained biotite monzonitic granite magma in the middle of the Huashan and Wenyu plutons were formed in the mixed source area, indicating that they had been experienced a longer cooling period and was more alkali-rich. These phenomena suggested a similar origin and evolution process of the magma in Huashan pluton comparing to Wenyu pluton. When the granitic magma formed at the deep crust, partial mantle magma injected into the system forming a mixed source magma. Therefore, there might be a similar gold potential in the Huashan pluton like the Wenyu pluton, and the gold mine prospecting work around the Huashan pluton should be strengthened. |
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| Keywords: | gold deposit biotite monzonitic granite zircon morphology mafic microgranular enclave typological evolution trend mixed source magma metallogenetic potential Xiaoqinling |
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