| 岛弧-陆缘弧环境斑岩Cu±Mo±Au矿床勘查：地质标志应用 |
| Received:September 01, 2017 Revised:July 21, 2018 点此下载全文 |
| 引用本文：QING Min,WANG WenCheng,LI WenBo,ZHANG LeJun,ZHANG Dai,HAN XianJu.2019.Exploration of porphyry Cu±Mo±Au deposits in island arc and continental margin arc environment: Application of geological indexes[J].Mineral Deposits,38(6):1223~1244 |
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| Author Name | Affiliation | | QING Min | China Gold Group Resources Co., Ltd., Beijing 100011, China | | WANG WenCheng | China Gold Group Resources Co., Ltd., Beijing 100011, China | | LI WenBo | School of Earth and Space Science, Peking University, Beijing 100871, China | | ZHANG LeJun | CODES ARC Center of Excellence in Ore Deposits, University of Tasmania, Hobart 7005, Tasmania, Australia | | ZHANG Dai | Gold Geological Institute of CAPF, Langfang 065000, Hebei, China | | HAN XianJu | Gold Geological Institute of CAPF, Langfang 065000, Hebei, China |
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| 基金项目:本文得到中国地质调查局矿产资源调查评价项目"全国金矿找矿勘查部署研究"（编号：1212011121128）资助 |
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| 中文摘要:斑岩Cu±Mo±Au矿床（以下简称斑岩铜矿）因其巨大的经济价值而倍受勘查界重视。文章基于国内外，尤其是国外斑岩型铜-金（多金属）矿床最新勘查和研究进展，系统总结了岛弧-陆缘弧环境斑岩铜矿勘查地质标志及其找矿应用实践，包括：①大地构造环境分析，宏观上确定斑岩铜矿勘查选区。弧环境斑岩铜矿勘查应重点部署在与大洋俯冲有关的岛弧、陆缘弧等增生造山火山岩浆弧环境；②区域及矿田构造解析，不断缩小找矿靶区。与弧/造山带形成演化应力有关的超壳深大断裂系统控制矿带空间展布，断裂、褶皱、火山（地层）以及岩浆侵入等矿田构造体系控制矿床（体）分布；③岩石化学成分、矿物组成以及岩石结构等含矿斑岩体特征及成矿专属性判断，确定斑岩铜矿找矿目标体；④蚀变分带对成矿斑岩体和富矿区（矿体）指向。从深部到浅部、从核心到外围，钙碱性斑岩铜矿蚀变类型分别为钠-钙（硅酸盐）化、钾（硅酸盐）化、青磐岩化（细化为高温阳起石内带、中温绿帘石中带和低温绿泥石外带）、绢英岩化和泥化；碱性斑岩铜矿蚀变组合为钙-钾化、钾化、内青磐岩化带（阳起石-赤铁矿-绿帘石带）、外青磐岩化带（钠长石-阳起石带）和远青磐岩化带（绿泥石带）；⑤岩帽特征对深部斑岩体和潜在富矿中心指向。钙碱性斑岩铜矿形成的岩帽由多孔状（晶洞发育）的硅质核，外侧高级泥化带（石英-明矾石带）和泥化带（高岭石±迪开石带）组成；碱性斑岩铜矿形成以钠长石化为核心、外围（上部）为钠长石-绢云母带的碱性岩帽；⑥脉体和角砾岩（筒）时空分布及其对勘查靶区（位）指向。A、B、D型脉以及C、M型脉等脉体类型、密度以及石英中残余硫化物详细填图是矿区勘查靶区定位和矿石品位预测有效指标之一；3大类、7种主要类型角砾岩在斑岩铜矿中时、空间分布可作为找矿评价的参考标志；⑦矿化元素、金属矿物和矿化类型分带及其找矿相互指示。从矿化中心到外围（浅部），出现[Mo-Cu→Cu-Mo（Au）→Cu-S（Au）]→[Pb-Zn（Au）]→Au-Ag（Mn）→Au（As，Sb）的元素分带，斑铜矿→黄铜矿→黄铁矿硫化物晕分带；斑岩型、矽卡岩型、次浅成环境脉型、高硫型和中硫型浅成低温热液型等矿化类型在斑岩铜矿成矿系统中分布具有显著的规律性，是勘查评价最重要的地质标志；⑧矿体剥蚀与保存，是评价矿田（体）找矿潜力重要因素。 |
| 中文关键词:地质学 岛弧-陆缘弧环境 斑岩Cu±Mo±Au矿床 地质标志 勘查应用 |
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| Exploration of porphyry Cu±Mo±Au deposits in island arc and continental margin arc environment: Application of geological indexes |
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| Abstract:Porphyry Cu±Mo±Au deposits (hereinafter referred to as porphyry copper deposits) are attracting much attention of exploration world because of their immense economic value. This paper systematically summarized prospecting geological marks with emphasis played on porphyry copper deposits occurring in island arc and continental margin arc environments and their applications in guiding exploration based on the most advanced research and the latest discovery, especially in abroad, including:① Determining the porphyry copper deposit exploration districts at macro level by tectonic environment analysis. The prospecting of arc environment porphyry copper deposits must focus in hyperplasia orogenic volcano magma arc environments, such as island arc and continental margin arc. ② Prospecting target areas continuously narrowing through structural analysis of districts and ore fields. Ultracrustal deep faults, which are related to the evolution stress of arc/orogenic belt, control ore belts spatial distribution. Structural systems of ore field, including fault, fold, volcanic(strata)and magma intrusion system, control the distribution of ore deposits(orebodies). ③ Determining metallogenic specialization and characteristics of porphyry orebodies such as chemical composition, mineral constituents, rock structures, then ascertaining the prospecting target. ④ Wall rock alteration zoning can be directly used to determine the ore-bearing porphyries and ore shoots. From deep part to shallow part,also from the core to the periphery, the alteration types of calcium alkaline porphyry copper deposits are in order of Na-Ca modification (silicatazation), K modification (silicification), propylitization (subdivided into high temperature actinolite inner subzone, middle temperature epidote central subzone and low temperature chlorite outside subzone),sericitic alteration and argillization. Accordingly, the alteration assemblages of alkaline porphyry copper deposit are Ca-K modification, K modification, inner propylitization(actinolite-hematite-epidote subzone), outer propylitization(albite-actinolite subzone) and further propylitization(chlorite subzone). ⑤ The lithocaps play an important role in searching for deep porphyries and potential center of porphyry bonanza. Lithocaps of calc-alkaline porphyry copper deposit is composed of cellular siliceous nuclear (geode development), outer advanced argillic belt (quartz-alunite zone) and argillic zone (kaolinite±dickite zone). Alkaline porphyry copper deposit exhibits albitization core in the center and alkaline lithocaps with albite-sericite band outside. ⑥ Spatial and temporal distribution of veins and breccias (chimneys) can point to the exploration target (position). Effective indicators of exploration target location and ore prediction grade are vein type and density of A, B, D and C, M-type veins through detailed mapping of residual sulfide in quartz. Identifying the 3 types and 7 subtypes of breccias can be used as prospecting and evaluation reference marks. ⑦ The zones of mineralized elements, sulfide minerals and mineralization types can all be directly used in the prospecting work and indicate each other. From the center (deep) of mineralition to the periphery (shallow), porphyry copper deposits exhibit typical metallogenic elements zoning of[Mo-Cu→Cu-Mo (Au)→ Cu-S(Au)]→[Pb-Zn(Au)]→Au-Ag(Mn)→Au(As, Sb), and the sulfide space zoning of bornite→chalcopyrite→ pyrite. The mineralization types of porphyry Cu±Mo±Au, skarn Cu±Au/Au/Zn-Pb-Cu-Ag, Zn-Cu-Pb-Ag±Au vein, high-sulfur and middle-sulfur type epithermal Au±Ag±Cu, which are distributed regularly in the porphyry copper mineralization system, are the most important geological indexes of exploration and evaluation. ⑧ Erosion and preservation of orebody are important factos in determining prospecting potential of orefield (orebody). |
| keywords:geology island arc and continental margin arc environment porphyry Cu±Mo±Au deposit geological index application of prospecting |
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