内蒙古长岭子铅锌矿床地质特征及找矿方向

Geological Characteristics and Metallogenic Direction of Changlingzi Pb-Zn Deposit,Inner Mongolia

长岭子铅锌矿床位于黄岗—甘珠尔庙成矿带西南段,主要受黄岗—甘珠尔庙复背斜及NE向次级断裂构造控制。结合该矿区地质工作成果,讨论了区域成矿地质背景及矿床地质特征,并就矿床成因、控矿因素进行了重点分析。研究表明:(1)矿区可主要划分为Ⅰ~#、Ⅱ~#两条矿带,其中Ⅰ~#矿带矿体主要分布于矽卡岩中,成因类型为矽卡岩型,Ⅱ~#矿带矿体主要分布于构造破碎带及绿帘石化蚀变带中,成因类型为热液脉型;(2)矿床矿石自然类型主要为原生硫化物矿石,氧化矿、混合矿极少,主要矿石结构为自形—半自形结构、他形粒状结构、交代结构,矿石构造主要为块状构造、脉状构造、浸染状构造、角砾状构造;(3)Ⅰ~#矿带的成矿阶段可划分为矽卡岩、磁铁矿、铁铜硫化物、铅锌硫化物等阶段,Ⅱ~#矿带的成矿阶段可划分为石英-毒砂-磁黄铁矿、石英-多金属硫化物、贫硫化物-碳酸盐等阶段;(4)Ⅰ~#、Ⅱ~#矿带的成矿物质均来自于造山带和地幔两个端元的贡献,显示其具有深源的特点,Ⅰ~#矿带的矿床成因类型为矽卡岩型,Ⅱ~#矿带的矿床成因类型为中—高温热液脉型;(5)矿床主要受控于地层、构造及岩浆岩等因素,即矿床的形成是大石寨组地层、NE向断层、燕山期中—酸性花岗岩综合作用的结果。在上述分析的基础上,进一步研究认为:矿区二叠系大石寨组碳酸盐岩地层与岩浆岩的接触带、Ⅰ~#矿带1 000 m标高以下区域以及Ⅰ~#矿带走向西南端等为有利找矿靶区。

Changlingzi Pb-Zn deposit is located in the southeast of Huanggang - Ganzhuermiao metallogenic belt, which is controlled by Huanggang - Ganzhuermiao anticlinorium and NE-direction secondary fracture structure. Based on some related geological working results of the mining area, the regional metallogenic background and deposit geological characteristics are discussed, besides that, the deposit genesis and ore-controlling factors are analyzed in detail. The study results show that：（1）the mining area can be divided into two ore belts （named Ⅰ # and Ⅱ# ore belts） , among them, the ore-bodies of Ⅰ #ore belt are occurred in skarn and it belongs to the skarn type ore-body ; Ⅱ # ore belt is mainly distributed in tectonic fracture belt and epidotization alteration belt, and it belongs to the hydrothermal vein type orebody ; （2）the natural ore types of the deposits in the mining area is mainly for primary sulfide ore, and con- tents of oxidized ore and mixed ore are less, the ore textures are mainly for idiomorphism - hypidiomorphie texture, xenomorphic granular texture and metasomatic texture, the ore structures are mainly for massive structure, vein structure, disseminated structure and brecciated structure;（3）the metallogenic period of Ⅰ# ore belt can be divided into skarn period, magnetite period, iron and copper sulfide period,lead and zinc sulfide period, and the metallogenic period of Ⅱ # ore belt can be divided into quartz-arsenopyrite-pyrrhorite period, quartz-polymetallic sulfide period, sulfide-barren-carbonate period ; （4）the metallogenic materials of Ⅰ # and Ⅱ# ore belts are both coming from the two units of orogenic belt and mantle, with the deep source characteristics, the deposit genesis of the ore-bodies of Ⅰ # ore belt is belongs to the skarn type deposit, and the deposit genesis of the ore-bodies of Ⅱ # ore belt is belongs to the medium-high temperature hydrothermal vein type deposit; （5）the formation of deposit is mainly controlled by strata, structure and magnatic rocks,that is to say, the formation of the ore-bodies is the combing action results of Dashizhai formation strata, Ne-direction fault and Yanshanian medium-acid granite. Based on the above discussion result in this paper, the further analysis results show that the contact area of Permian Dashizhai formation carbonate strata,the deep area below 1 000 m of Ⅰ # ore belt and the southwest along the towards direction of 1 # ore belt are the favorable prospecting target areas of the mining area.