内蒙古硐子铅锌矿床地质特征及矿床成因探讨

Geological characteristics and genesis of the Dongzi Pb-Zn deposit,Inner Mongolia

内蒙古硐子铅锌矿床位于华北克拉通北缘,矿体受近东西向断裂控制,呈脉状产出于闪长岩和安山岩接触的断裂蚀变带中。金属矿物以黄铁矿、方铅矿、闪锌矿为主,其次有黄铜矿、黝锑银矿、毒砂等,其中,黝锑银矿是该矿床主要的独立银矿物。成矿作用过程可划分为黄铁矿—闪锌矿阶段,方铅矿—闪锌矿等多金属硫化物阶段,石英—黄铜矿阶段和石英—碳酸盐阶段4个阶段。围岩蚀变以硅化、碳酸盐化、绿泥石化和绢云母化等中低温热液蚀变为主。矿床的形成可能与近同期的火山—次火山岩浆作用相关,为浅成低温热液型矿床,岩浆热液在有利的构造部位与大气降水的混合可能是形成矿床的主要机制。

The Dongzi Pb-Zn deposit located in the northern margin of North China Craton, is controlled by the nearly EW- trending faults.The ore bodies occur in the fauhed alteration zone in the contact zone of diorite and andesite in the vein form. The ore minerals mainly arc pyrite, galena and sphalerite with minor chalcopyrite, freibergite, arsenopyritc etc.. The freibergite is the main free siliver mineral. The hydrothermal mineralization stage can be subdivided into four stages as followings： pyrite-sphalerite stage, galena -sphalerite polymetallie sulfide stage, quartz-chalcopyrite stage and quartz-carbonate stage. Mineralization-related hydrothermal alterations are dominated by silicification, carbonatation, chloritization and sericitization etc.. The deposit belongs to epithermal type deposit and is closely related to the Jurassic volcanism-subvolcaism.Thc mixing of hydrothermal fluid and meteoric water in the favorable structural place resulted in rapid precipitation of ore-forming materials.