大兴安岭中南段夕卡岩型铅锌矿床地质特征及成因

大兴安岭地区是中国东部重要的成矿集中区之一。夕卡岩型金属矿床多分布于二叠系大理岩或结晶灰岩夹层内,复背斜轴部的虚脱带和断层交汇处是赋矿的有利场所。白音诺尔和浩布高是近年来发现的两个大型铅锌矿床,均经历了中温、高温两个矿化阶段;矿石铅同位素属于放射性成因铅,暗示其成矿物质以壳源铅为主;硫化物硫同位素均多为较低正值并呈塔式分布,具有岩浆硫特征;与硫化物共生的石英单矿物的氧同位素表明矿床成矿流体具有深部岩浆水与大气降水或地层水混合的特征,矿床应属于与深部隐伏岩体有关的中—高温夕卡岩型铅锌矿床,矿区深部隐伏岩体的侵入产生岩浆热液并携带Pb、Zn等成矿物质与地层水或大气降水混合,受构造作用控制形成的该类型矿床。

Geological characteristics and genesis of skarn type lead-zinc deposit in the central-southern Daxinganling belt

The Daxinganling belt is one of important mineralization concentrated area in eastern China. The skarn type polymetallic metal deposit is located in Permian marble or crystalline limestone intercalation. The collapse zone located in axis of complex anticline and fault junction are favorable place for deposition of metallogenic elements. The large sized Baiyinnuoer and Haobugao Pb-Zn deposits were discovered in recent years. Both Pb-Zn deposits are experienced in intermediate temperature and high temperature mineralization stages and both ore lead isotopes belong to radioactive origin, which indicated that ore-forming minerals mainly are from crust source lead, and the sulfur isotope of sulfide minerals mostly have lower positive values and distributed in babel form, which indicated that the deposits have the characteristics of magmatic sulfur. The study result of oxygen isotope of quartz associated with sulfideshows that the ore-forming fluid mainly came from deep magmatic fluid, and mixed with atmospheric water or strata water. Therefore, the deposit should belong to the intermediate-high temperature skarn lead-zinc deposit related to deep concealed rock mass.