内蒙古长汉卜罗铅锌银矿床地质特征及成因探讨

Geological characteristics and discussion on genesis of the Changhanboluo Pb- Zn- Ag deposit,Inner Mongolia

长汉卜罗铅锌银矿床位于华北克拉通北缘。矿体受东西、北东向断裂控制,主要以脉状、透镜状赋存于石英斑岩、花岗闪长岩、安山岩内及不同岩性接触带。金属矿物以方铅矿、闪锌矿、黄铁矿为主,其次为黄铜矿、毒砂、白铁矿、黝铜矿、银黝铜矿等。围岩蚀变主要在矿脉两侧发育,包括黄铁矿化、绢云母化、硅化、绿泥石化、绿帘石化、碳酸盐化等。成矿过程可划分为3个阶段:石英—黄铁矿阶段(Ⅰ阶段)、多金属硫化物阶段(Ⅱ阶段)和石英—碳酸盐阶段(Ⅲ阶段)。矿床形成可能与近同期的火山—次火山岩浆作用相关,为次火山热液型矿床。

The Changhanboluo Pb - Zn - Ag deposit is located in the northern margin of the North China Craton. The orebodies are controlled by EW - and NE - trending faults and hosted in quartz porphyry, granodiorite, andesite and the contact zones of differ- ent rocks. The metalllc minerals are mainly galena, sphalerite, pyrite, with minor chalcopyrite, arsenopyrite, marcasite, tetrahedrite, freibergite etc. Ore - related hydrothermal alteration is well developed on both sides of the veins, dominated by pyritization, sericitiza- tion, silication, chloritization, epidotization, carbonatation etc. The hydrothermal mineralization stage can be subdivided into three sta- ges ： quartz - pyrite stage, polymetallic sulfide stage and quartz - carbonate stage. The deposit belongs to subvolcaism hydrothermal de- posit and is closely related with the volcanism -snbvolcaism magmatism.