| 西藏斑岩-矽卡岩-浅成低温热液铜多金属矿成矿作用、勘查方向与资源潜力 |
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| 引用本文：唐菊兴,王勤,杨欢欢,高昕,张泽斌,邹兵.2017.西藏斑岩-矽卡岩-浅成低温热液铜多金属矿成矿作用、勘查方向与资源潜力[J].地球学报,38(5):571-613. |
| DOI：10.3975/cagsb.2017.05.02 |
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| 基金项目:国土资源部公益性行业科研专项(编号: 201511017)；中国地质调查局二级项目(编号: DD20160026) |
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| 中文摘要:西藏主要成矿带是东特提斯成矿域的重要组成部分。1999年以来, 中国地质调查局地质大调查的全面实施, 国家公益性基础研究的不断深入和商业性勘查的及时跟进, 真正意义上的找矿突破得以实现。论文在前人资料和研究成果综述的基础上, 结合研究团队近年来的研究进展, 总结了西藏各成矿带主要矿床的地质特征和成矿规律, 梳理了若干影响勘查评价和找矿突破的重大问题, 构建了主要矿集区的勘查模型, 提出进一步找矿方向和资源潜力。西藏四大成矿带特色鲜明, 东特提斯成矿域集聚了从新特提斯洋俯冲-碰撞的多种矿床类型, 控矿因素复杂, 主要矿床类型为斑岩-矽卡岩-浅成低温热液型铜多金属和岩浆热液脉型矿床, 成岩成矿时代从170 Ma到12 Ma, 具有成矿时代跨度大、矿床类型丰富、成矿元素复杂、矿石质量较好之特点, 已经成为我国最重要的资源储备基地。藏东玉龙成矿带除了斑岩型铜(钼)矿以外, 斑岩体外接触带的矽卡岩型矿床具有重要工业价值, 如玉龙II、V号矿体、昂青银铅锌(铜)矿, 成岩成矿时代在40~38 Ma, 成矿岩体和矿体受北西向走滑构造控制的背斜控制。冈底斯成矿带类型发现识别出赋存于林子宗群典中组的低硫化浅成低温热液型矿床, 显示谢通门—昂仁县以西林子宗群分布区寻找斑岩-浅成低温热液型铜多金属(银、金、铅锌)矿床具有重要意义; 矿床学研究成果作为构造地质背景确定的指针之一, 认为印度大陆和亚洲大陆的碰撞事件发生在52~50 Ma, 至少典中组火山岩还是陆缘弧的产物, 并形成典型的浅成低温热液矿床, 甚至斑岩-浅成低温热液矿床; 含矿斑岩接触带有碳酸盐岩, 接触带和深部需要勘查评价矽卡岩型铜多金属矿体或铅锌银矿体, 90~13 Ma侵位的花岗斑岩、花岗闪长斑岩可形成规模较大的矽卡岩型矿床, 甲玛、驱龙外围的知不拉、邦铺、洞中拉—蒙亚啊矿集区、努日、尕尔穷—嘎拉勒等矿床均具有相似的特征, 而这种类型矿体较之斑岩型铜(钼)矿更具工业价值。班公湖—怒江成矿带多龙矿集区120~116 Ma的斑岩-浅成低温热液成矿系统形成斑岩型-高硫化浅成低温热液型-隐爆角砾岩型矿床, ~110 Ma的陆相安山质火山岩——美日切错组(K1m), 作为良好的成矿后盖层, 是该类矿床得以保存的必要条件; 班—怒结合带两侧形成于140~110 Ma的则弄群、多尼组、去申拉组、美日切错组等安山质、英安质、流纹质火山岩具有强烈的蚀变, 发育火山机构, 是新特提斯洋俯冲形成的产物, 成矿地质背景类似于南美安第斯成矿带, 显示良好的成矿潜力。西藏已经初步查明的铜资源量 >6 000万吨, 钼资源量>300万吨, 共伴生金>1 000 t, 共伴生银>25 000 t, 铅锌资源量>1 000万吨, 已经成为我国最重要的有色金属储备基地, 研究认为西藏铜的资源潜力将超过15 000万吨。 |
| 中文关键词:斑岩-浅成低温热液型 斑岩-矽卡岩型 冈底斯成矿带 班公湖—怒江成矿带 成矿潜力 陆相火山岩 西藏 |
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| Mineralization, Exploration and Resource Potential of Porphyry-skarn-epithermal Copper Polymetallic Deposits in Tibet |
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| Abstract:Main metallogenic belts in Tibet have become the important part of the Eastern Tethyan metallogenic domain. Since 1999, with the full implementation of the geological survey by China Geological Survey and the deepening of the basic research on national public welfare and the timely follow-up of commercial exploration, the real breakthrough in prospecting has been realized. Based on the review of the previous data and research results in combination of the recent progress in research by the authors’ research group, this paper summarizes the geological characteristics and metallogenic regularity of the main deposits in the metallogenic belts, Tibet, arranges some major problems affecting the exploration and evaluation as well as prospecting breakthrough, builds an exploration model of the main ore district, and puts forward the further prospecting direction and resource potential. Four main metallogenic belts in Tibet are distinctive. The Eastern Tethyan metallogenic domain concentrates a variety of deposit types from Neo-Tethys subduction to collision, with the complicated ore-controlling factors. The main ore deposits are porphyry-skarn-epithermal copper polymetallic deposits and magmatic hydrothermal vein deposits, and their metallogenic ages are from 170 to 12 Ma. Tibet has become the most important resource reserve base in China with large span of metallogenic ages, various types of deposits, complex metallogenic elements and good ore quality. In the Yulong metallogenic belt of east Tibet, besides porphyry copper (molybdenum) deposits, skarn deposits in the external contact zone of porphyry, such as Yulong No. II and No. V orebodies and Angqing silver-lead-zinc (copper) orebody, also have important industrial values. The diagenetic and metallogenic epoch is 40~38 Ma, and the ore-forming rock and orebody are controlled by the anticline of the NW-striking slip structure. The identification of the existence of low sulfidation epithermal deposits in the Dianzhong Formation of Linzizong Group in the Gangdise metallogenic belt shows the important significance of exploration of the porphyry-epithermal copper polymetallic (silver, gold, lead and zinc) deposits in the distribution area of Linzizong Group in the West of Xietongmen-Angren County. Research results of mineral deposits can be one of the pointers for the determination of the tectonic setting. The collision event of Indian and the Asian continents occurred at 52~50 Ma. At least the Dianzhong volcanic rock is the product of the continental margin arc, and the typical epithermal deposits, even porphyry-epithermal deposits, were formed. If ore-bearing porphyry contact has carbonate rocks, it is necessary to evaluate the skarn type copper polymetallic orebodies or lead-zinc silver orebodies along the contact zone and in the depth. Granite porphyry and granodiorite porphyry which intruded in 90~13 Ma might form larger skarn deposits, such as Jiama, Zhibula in the Qulong periphery, Bangpu, Dongzhongla-Mengya’a ore concentration area, Nuri, Gaerqiong and Galale deposits with similar characteristics. Orebodies of this type have more industrial values than porphyry copper (molybdenum) orebodies. The porphyry-high sulfidation epithermal-cryptoexplosive breccia type deposits were formed by the porphyry-epithermal metallogenic system in 120~116 Ma in the Duolong ore concentration area of the Bangong Co-Nujiang metallogenic belt. The continental andesitic volcanic rock-Meiriqiecuo Formation (K1m) (110 Ma) serves as the good post-mineralization cover, which constitutes one of the necessary conditions for the preservation of this kind of deposits. Strong alterations in the andesitic, dacitic and rhyolitic volcanic rocks of Zenong Group, Anni Formation, Qushenla Formation, Meiriqiecuo Formation (140~110 Ma) on both sides of the Bangong Co-Nujiang junction zone and the rich volcanic apparatuses are the products of the Neo-Tethys subduction. The metallogenic geological background is similar to that of the Andean metallogenic belt in South America, showing good metallogenic potential. Tibet has initially identified copper resources of >60 million tons, molybdenum resources of >3 million tons, a total of associated gold > 1 000 tons, associated silver of > 25 000 tons, and lead and zinc resources of >10 million tons. Tibet has become China's most important nonferrous metal reserve base, and this study concludes that the copper resource potential in Tibet will exceed 150 million tons. |
| keywords:porphyry-epithermal type porphyry-skarn type Gangdise metallogenic belt Bangong Co–Nujiang metallogenic belt metallogenic potential continental volcanic rock Tibet |
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