贵州万山—松桃铅锌矿控矿因素及成矿过程分析

Analysis on ore-controlling factors and metallogenic process of lead-zinc ore in Wanshan-Songtao,Guizhou

万山-松桃铅锌矿地处鄂湘黔铅锌成矿带南段,所属大地构造单元为上扬子地台东南部被动边缘与雪峰基底逆冲过渡带,是贵州重要铅锌矿成矿区之一。区内铅锌矿床的赋矿层位清虚洞组为汇聚背景下被动大陆边缘盆地沉积的产物,主要形成于碳酸盐台地边缘滩(礁)相环境,且Pb、Zn地球化学背景值高,为成矿物质初始富集及后期成矿提供矿源;区域性铜仁-花垣深大断裂与江口-保靖断裂控制矿床(点)分布,其旁侧的次级构造控制矿体产出形态及规模。同位素研究表明,形成铅锌矿床的矿化剂硫主要来源于下伏地层中的蒸发岩和同期沉积海水;形成脉石矿物的碳来源于海相碳酸盐岩和原生碳酸岩的去气作用;而成矿金属元素主要来源于壳源;成矿流体具后生、低温、中高盐度热液特征,与同沉积建造水和大气降水活动有关,可能有部分变质水混入。铅锌矿床在成因类型上可归属于MVT型,主成矿期为加里东期,存在华力西期叠加特点。

Wanshan-Songtao lead-zinc deposit is located in the southern section of E-Xiang-Qian Lead-zinc metallogenic belt,the geotectonic element belongs to the passive edge and the overthrust transition zone of snowcapped basement in the southeast of the upper Yangtze platform,is also one of the important Lead-zinc metallogenic province in Guizhou.Research suggests that regional lead-zinc deposit is hosted by dolomitite of the Qingxudong formation which is passive continental margin basin sedimentary products under convergent background,mainly formed in carbonate platform edge beach (reef) facies environment,and Pb,Zn localization background is high,which provided mineral resources for initial enrichment of metallogenic materials and for later metallogenesis.The emulti-stage activities of the regional Tongren-Huayuan deep fault and Jiangkou-Baojing fault control the distribution of deposits (points),the production form and scale of the ore body is controlled by secondary structures on the lateral side of deep faults. The isotopic evidence shows that the mineralizing agent sulfur forming the pb-zn deposit is mainly derived from evaporite and contemporaneous sedimentary seawater in the underlying strata;and the metallogenic metallic elements are mainly from customers,The ore-forming fluid has the characteristics of epigenetic,low temperature,medium and high salinity hydrothermal fluid,which is related to the activities of synsedimentary formation water and meteoric precipitation as well as possible addition of partially metamorphic water.Mineral deposit genesis belongs to the MVT deposit,the main metallogenic stage is caledonian,which has the superposition characteristics of variscan.