| 东昆仑祁漫塔格地区乌腊德石墨矿床地球化学特征及成矿机制研究 |
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| 引用本文： | 唐名鹰,华磊,丁正江,董振昆,王炜晓,翟孝志,王汝杰,郑成龙.东昆仑祁漫塔格地区乌腊德石墨矿床地球化学特征及成矿机制研究[J].现代地质,2022,36(6):1475-1485. |
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| 作者姓名： | 唐名鹰 华磊 丁正江 董振昆 王炜晓 翟孝志 王汝杰 郑成龙 |
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| 作者单位： | 1.山东省第八地质矿产勘查院,山东 日照 2768002.山东省地矿局 有色金属找矿与资源评价重点实验室,山东 日照 2768003.山东省第六地质矿产勘查院,山东 威海 2642094.山东省深部金矿探测大数据应用开发工程实验室,山东 威海 2642095.山东理工大学 资源与环境工程学院,山东 淄博 2550006.青岛地质工程勘察院,山东 青岛 266000 |
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| 基金项目： | 山东省深部金矿探测大数据应用开发工程实验室开放课题项目(SDK202205) |
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| 摘 要： | 乌腊德石墨矿床是东昆仑祁漫塔格地区新发现的晶质石墨矿床,矿体赋存于古元古代白沙河组条带状大理岩层内,呈带状、似层状,局部呈透镜状产出。对该矿床进行地球化学特征、碳同位素研究,并讨论了其成矿机制。研究结果表明,石墨大理岩主量元素整体表现为低硅、低碱、高钙、高烧失量的特点,微量元素显示Ba、Rb、Th、Sr、P相对富集,K、Zr、Ti相对亏损,稀土总量较低,表现为轻稀土富集、重稀土亏损的特点,具中等负Eu异常,微弱负Ce异常,其成矿原岩为一套浅水环境下沉积的灰岩地层,成岩环境为缺氧的还原环境,沉积时水体介质为咸水。乌腊德矿区大理岩围岩的δ13CPDB为+1.4‰~+3.3‰,与海洋碳酸盐岩的碳同位素分布区间一致,石墨单矿物的δ13CPDB为-5.8‰~-5.4‰。综合研究认为,区内三叠纪石英闪长岩为石墨矿床的形成提供了良好的热力学条件,使得大理岩脱碳反应形成的CO2与早期变质作用形成的晶质石墨和有机沉积物脱挥发分形成的CH4发生反应后,沿构造裂隙进一步迁移并集中,形成区域变质-热液改造型石墨矿床。
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| 关 键 词： | 地球化学 碳同位素 成因机制 乌腊德石墨矿 祁漫塔格地区 |
| 收稿时间： | 2022-01-04 |
| 修稿时间： | 2022-03-01 |
Geochemical Characteristics and Metallogenic Mechanism of the Wulade Graphite Deposit in the Qimantage Area,East Kunlun |
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| TANG Mingying,HUA Lei,DING Zhengjiang,DONG Zhenkun,WANG Weixiao,ZHAI Xiaozhi,WANG Rujie,ZHENG Chenglong.Geochemical Characteristics and Metallogenic Mechanism of the Wulade Graphite Deposit in the Qimantage Area,East Kunlun[J].Geoscience——Journal of Graduate School,China University of Geosciences,2022,36(6):1475-1485. |
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| Authors: | TANG Mingying HUA Lei DING Zhengjiang DONG Zhenkun WANG Weixiao ZHAI Xiaozhi WANG Rujie ZHENG Chenglong |
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| Abstract: | The Wulade graphite deposit is a newly discovered crystalline graphite deposit in the Qimantage area, East Kunlun. The banded, lamellar and minor lenticular ore bodies occur in the banded marble strata of the Paleoproterozoic Baishahe Formation, which are mainly composed of graphite marble. In this paper, we carried out the geochemical and carbon isotope analysis and shed new light on metallogenic mechanism of the deposit. Results show that the graphite marbles have low silicon and alkali, and high LOI and calcium contents. They show enrichment of Ba, Rb, Th, Sr, P, and depletion of K, Zr, Ti, as well as low total REE concentrations. These rocks are characterized by enrichment of light REE and depletion of heavy REE, with a moderate negative Eu anomaly and weak negative Ce anomaly. These geochemical features suggest that the ore-forming protolith is sedimentary limestone strata in shallow water environment, with diagenetic environment of anoxic reduction and salt water medium. The marbles in Wulade deposit have δ13CPDB of +1.4‰ to +3.3‰, which is consistent with those of marine carbonatite. The graphite have δ13CPDB of -5.8‰ to -5.4‰, indicating a derivation from the mixture of marble and biogenic organic sediments. Therefore, we suggest that the Triassic quartz diorite in the area provided good thermal conditions for the formation of graphite deposits. The crystalline graphite and organic sediments were formed by the early metamorphism in the protoliths; the latter reacted with the carbonate strata, further migrated and concentrated along the structural fractures, and thus formed the sedimentary metamorphic-hydrothermal transformation type graphite deposits. |
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| Keywords: | geochemistry carbon isotope genetic mechanism Wulade graphite deposit Qimantag area |
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