滇西白象厂铅-锌-银-(铜-金)多金属矿床矽卡岩型铁-铜-(金)矿化类型的发现及找矿潜力分析  

Discovery and prospecting potential analysis of skarn Fe-Cu-(Au) mineralizationtype in Baixiangchang Pb-Zn-Ag-(Cu-Au) polymetallic deposit in West Yunnan

作　　者：罗达 韩润生[1,2] 王明志[1,2] Mahmoud.H.H.N LUO Da;HAN Runsheng;WANG Mingzhi;Mahmoud.H.H.N(Faculty of Land Resources Engineering,University of Science and Technology,Kunming 650093,Yunnan,China;Southwest Institute of Geological Survey of China Non-Ferrous Metals Resource Geological Survey,Kunming 650093,Yunnan,China)

机构地区：[1]昆明理工大学国土资源工程学院,云南昆明650093 [2]有色金属矿产地质调查中心西南地质调查所,云南昆明650093

出　　处：《矿产与地质》2020年第4期710-723,共14页Mineral Resources and Geology

基　　金：云岭学者资助项目(2014);国家重点研发计划项目(2018YFC0603902);云南省矿产资源预测评价工程实验室项目(2010)共同资助。

摘　　要：滇西白象厂铅-锌-银-(铜-金)多金属矿床是“三江”特提斯成矿域金沙江—哀牢山富碱斑岩带中的典型矿床之一,主要由与喜马拉雅期石英二长斑岩密切相关的斑岩型铜-金(钼)矿化和热液脉型铅-锌-银矿体组成。目前该矿床浅部的主要成矿类型和开采对象是大理岩中热液脉型铅-锌-银矿体,但矿床深部是否存在矽卡岩型成矿类型和斑岩型多金属成矿系统至今不明,直接影响到矿床资源潜力的判断和深部找矿工程部署。为此,应用大比例尺蚀变岩相填图方法,在矿区坑道PD7-3和PD2-3,发现矽卡岩型铁-铜-(金)矿化(体),且矽卡岩内分带性完整,从内接触带→外接触带,特征矿物组合依次为透辉石-石榴子石(钙铁-钙铝榴石)→绿帘石-阳起石-角闪石-磁铁矿→黄铜矿-斑铜矿-(辉钼矿-金)-磁黄铁矿-石英-萤石-方解石;各蚀变带内∑REE、LREE/HREE、(La/Yb)N、(La/Sm)N总体呈逐渐降低的趋势,表明成矿流体交代作用明显。弱Eu和Ce负异常→强Eu正异常和弱Ce负异常→弱Eu正异常和Ce负异常,指示矽卡岩型矿石形成于较高温氧化环境。矽卡岩型矿石Y/Ho比值相近,表明它们具有一致的成矿物质来源。在此基础上,与区域内毗邻的北衙超大型金多金属矿床、马厂箐大型铜钼金多金属矿床对比研究,认为该矿床深部具有矽卡岩型铜-金矿的找矿潜力。本次发现的矽卡岩型铁-铜-(金)矿化类型,不仅为该矿床斑岩型成矿系统提供了新依据,而且对矿床深部及外围找矿勘查具有重要意义,对“三江”特提斯成矿域成矿研究的价值不言而喻。Baixiangchang Pb-Zn-Ag-(Cu-Au)polymetallic deposit is one of the typical deposits in the Jinshajiang-Ailaoshan alkali-rich porphyry belt in the Tethys metallogenic domain of Sanjiang.It is mainly composed of porphyry copper-gold(molybdenum)mineralization and hydrothermal vein-type lead-zinc-silver orebodies that are closely related to the Himalayan quartz monzonite porphyry.At present,the main metallogenic types and mining objects in the shallow part of the deposit are hydrothermal vein-type lead-zinc-silver ore bodies in the marble.But it is unknown until now whether there is the skarn-type metallogenic type and porphyry-type polymetallic metallogenic system in the deep part of the deposit.The problem directly affects the judgment of the resource potential of the deposit and the deployment of deep prospecting project.For this reason,using a large-scale altered rock face mapping method,in the mine tunnels PD7-3 and PD2-3,a skarn-type iron-copper-(gold)mineralization(body)is first discovered,and the skarn inner zone is in the integrity.From the inner contact zone to the outer contact zone,the characteristic mineral combinations are listed as follows.Diopside-garnet(andradite-grossularite)→chloridite-apatite-hornblende-magnetite→chalcopyrite-bornite-(molybdenite-gold)-pyrrhotine-quartz-fluorite-calcite.In the alteration zones,the values ofΣREE,LREE/HREE,(La/Yb)N,(La/Sm)N generally show a gradually decreasing trend,indicating that the ore-forming fluid has a significant effect on metasomatization.For weak Eu and Ce negative anomalies→strong Eu positive anomaly and weak Ce negative anomaly→Weak Eu positive anomaly and Ce negative anomaly,it is indicated that skarn-type ores are formed in a higher temperature oxidation environment.The skarn-type ores have similar Y/Ho ratios,indicating that they have a consistent source of ore-forming materials.On the basis of a comparative study with Beiya super large-scale gold polymetallic deposit and Machangqing large copper-molybdenum-gold polymetallic deposit adjacent t

关 键 词：矽卡岩型 铅-锌-银-(铜-金)多金属矿床 斑岩型成矿系统 三江特提斯成矿域 滇西白象厂 

分 类 号：P618.4[天文地球—矿床学] P618.5[天文地球—地质学]