摘要
兰坪盆地白秧坪铅锌铜银多金属矿床由数条矿脉构成,进而划分为多个矿段,过去对不同矿段的矿床地质及矿体矿化特点缺乏研究。本文在分析前人资料基础上,结合野外地质调查显示,矿区主要发育中生代地层和呈近南北向、北西西向、北东向3组断裂。不同矿段矿体均受断裂控制,对围岩岩性的选择性不强,矿体直接赋存于断裂带内(主要),局部容矿于裂隙、劈理和热液岩溶垮塌形成的空间中,后生充填成矿,形成角砾状、块状、脉状、浸染状矿石。不同矿段矿物组成和元素组合有差别,李子坪和吴底厂矿段以闪锌矿、细硫砷铅矿、方铅矿、灰硫砷铅矿、雄黄、雌黄为主,构成Pb-Zn-As-Sb-Ag组合;富隆厂矿段矿石矿物以闪锌矿、灰硫砷铅矿、方铅矿、黝铜矿系列矿物、车轮矿、辉银矿、汞银矿为主,构成Pb-Zn-Cu-Ag组合;白秧坪矿段矿石矿物以黝铜矿系列矿物、辉铜矿、黄铜矿、灰硫砷铅矿、辉砷钴矿、硫钴镍矿、含钴毒砂、方铅矿、闪锌矿等为主,构成Cu-Co-As-Zn-Pb组合。综合分析认为,白秧坪矿区发生过两次热液成矿事件,一期为古新世末—始新世初期以铜为主的矿化,另一期是始新世末—渐新世早期以铅锌为主的矿化,含铅锌成矿流体活化前期铜矿化在富隆厂和白秧坪矿段形成铅锌铜等多金属组合;成矿很可能出现在区域强烈挤压后的应力转换阶段,此阶段围岩开放空间发育,成矿流体灌入成矿。
The Baiyangping lead-zinc-copper-silver polymetallic deposit in Lanping basin is composed of a few ore veins and can be divided into several ore blocks.Researches on ore geological features and mineralization characteristics of different ore blocks of the ore deposit have been very insufficient.Based on an analysis of data available in combination with field geological survey,it can be concluded that the strata in the ore district comprise mainly Mesozoic sedimentary rocks.Three main cross-cutting fault systems are observed in the ore district,namely nearly north-south-striking faults,NWW-striking faults and NE-SW-striking faults.Ore bodies are evidently controlled by faults in different ore blocks and have no obvious affinity with any special strata and lithology;they primarily occur in the fault zone,with some in fractures,cleavages and space of wall rock collapse.There are breccia ore,massive ore,veinlike ore and disseminated ore,suggesting they were formed by filling epigenetic mineralization.In different ore blocks,mineral composition and association of elements are somewhat different： in Liziping and Wudichang ore blocks,the main minerals include sphalerite,gratonite,galena,jordanite,realgar and orpiment,comprising the Pb-Zn-As-Sb-Ag element assemblage;in Fulongchang ore blocks,the main minerals include sphalerite,jordanite,galena,tetrahedrite series minerals,bournonite,argentite and kongsbergite,composing the Pb-Zn-Cu-Ag element assemblage;in Fulongchang ore blocks, the main minerals include tetrahedrite series minerals,chalcocite,chalcopyrite,jordanite,cobaltine,siegenite,cobalt-bearing arsenopyrite,galena and sphalerite,composing the Cu-Co-As-Zn-Pb element assemblage.A comprehensive analysis reveals that there were two mineralization events in the Baiyangping ore district,one responsible for the main copper mineralization between late Paleocene and early Eocene,the other for main lead and zinc polymetallic mineralization in late Eocene-early Oligocene period.The lead and zinc ore-forming fluids activated early copper element and formed the Pb-Zn-Cu polymetallic assemblage in Fulongchang and Baiyangping ore blocks.The mineralization probably occurred at the stage of short-term stress relaxation after strong extrusion when the wall rocks supplied open space,and ore-forming fluids poured into the space to form ore deposit.
出处
《岩石矿物学杂志》
CAS
CSCD
北大核心
2011年第3期507-518,共12页
Acta Petrologica et Mineralogica
基金
国家科技支撑计划资助项目(2006BA01A08)
973资助项目(2009CB421008)
国家自然科学基金资助项目(U09336051)
国土资源大调查资助项目(1212010818096)
关键词
兰坪盆地
白秧坪
铅锌多金属
矿床地质
Lanping basin
Baiyangping
lead-zinc polymetallic deposit
geological feature
