| 西藏冈底斯成矿带西段鲁尔玛晚三叠世斑岩型铜(金)矿点的发现及意义 |
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| 引用本文： | 刘洪,黄瀚霄,张林奎,李光明,欧阳渊,黄勇,吕梦鸿,兰双双.西藏冈底斯成矿带西段鲁尔玛晚三叠世斑岩型铜(金)矿点的发现及意义[J].沉积与特提斯地质,2021,41(4):599-611. |
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| 作者姓名： | 刘洪 黄瀚霄 张林奎 李光明 欧阳渊 黄勇 吕梦鸿 兰双双 |
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| 作者单位： | 1. 中国地质调查局成都地质调查中心, 四川 成都 610081;2. 成都理工大学地球科学学院, 四川 成都 610059;3. 中国地质调查局应用地质调查中心, 四川 成都 610000;4. 四川省冶金地质勘查院, 四川 成都 610051 |
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| 基金项目： | 国家重点研发计划(2019YFC0605201，2018YFC0604103，2016YFC0600308)、国家自然科学基金重点项目(92055314, 91955208)、中国地质调查项目(DD20221776，DD20190542，DD20221866，DD20221873)、中国科学院战略性先导科技专项(XDA20070304)、甘肃省文县阳山金矿资源基地综合调查和西南地质科技创新中心青藏高原国际大科学计划 |
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| 摘 要： | 鲁尔玛斑岩型铜(金)矿为冈底斯成矿带西段新发现的斑岩型矿点，目前已发现赋存于石英二长斑岩体中的斑岩型铜矿体1条，赋存于构造破碎带中的热液型脉状金(铜)矿体1条、热液型脉状铜矿体1条。以鲁尔玛含矿斑岩为中心，依次发育钾硅酸盐化、绢英岩化、青磐岩化，表现出斑岩型矿床的典型蚀变分带模式。其中，热液脉体从早到晚被可划分为：钾硅酸盐化脉(A脉)、石英-金属硫化物脉(B脉)以及石英-绿帘石-碳酸盐化脉(D脉)。这一新的发现，证实冈底斯成矿带西段具有斑岩型铜(金)矿床的找矿潜力，有望将冈底斯斑岩型铜矿带向西延伸近200km，同时也表明拉萨地体南缘的冈底斯成矿带斑岩型铜成矿作用最晚应该开始于晚三叠世。鲁尔玛斑岩型铜(金)矿点的发现，对深入理解冈底斯斑岩铜(金)矿带的成矿作用，完善冈底斯成矿带的成矿理论，更好地评价冈底斯西段找矿潜力，指导该地区的找矿突破，均具有重要意义。
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| 关 键 词： | 鲁尔玛 冈底斯 斑岩型铜(金)矿点 晚三叠世 俯冲 |
| 收稿时间： | 2020/3/15 0:00:00 |
| 修稿时间： | 2020/5/15 0:00:00 |
Luerma, a newly discovered late Triassic porphyry copper-gold ore-spot in the western Gangdise metallogenic belt, Tibet |
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| Institution: | 1. Chengdu Center, China Geological Survey, Chengdu 610081, China;2. College of Earth Sciences, Chengdu University of Technology, Chengdu 610059, China;3. Research Center of Applied Geology, China Geological Survey, Chengdu 610000, China;4. Sichuan Institute of Metallurgical Geology & Exploration, Chengdu 610051, China |
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| Abstract: | Previously, almost all the porphyry copper-gold deposits in the Gangdise metallogenic belt are located at the eastern section of the Gangdise metallogenic belt, and their mineralization ages are younger than the late Triassic epoch. This paper discusses Luerma, the newly discovered late Triassic porphyry copper-gold ore-spot in the western Gangdise metallogenic belt. Zircon U-Pb dating and molybdenite Re-Os dating indicate that Luerma copper-gold occurrence is with a 212 Ma mineralization age, implying it is related to the subduction process of the Indian ocean plate northward to the Gangdise plate in the late Triassic epoch. The Luerma copper-gold ore-spot developed typical porphyry hydrothermal alteration zones, which can be divided into a potassium-silicification zone, asericitization zone, a clayization zone, and a propylitization-propylitization zone from ore-bearing quartz monzonite porphyry to wall rocks, respectively. By so far, three ore bodies are determined in Luerma copper-gold occurrence:one porphyry copper orebody occured in quartz monzonite porphyry, one hydrothermal vein gold-copper orebody and one hydrothermal vein-typed copper orebody occured in structural fracture zones respectively. Moreover, three main types of hydrothermal veins have been identified based on their mineral assemblages,cutting relationship and alteration features: the potassium-silicification vein (A-typed vein), the medium-term quartz-polymetallic sulfides vein (B-typed vein), and the epidote-carbonatation (D-typed vein), respectively. The discovery of Luerma ore-spot suggests that the western part of the Gangdise metallogenic belt is potential for porphyritic copper-gold deposits. |
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| Keywords: | Luerma Gangdise porphyry copper-gold occurrence late Triassic subduction |
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