甘肃省霍勒扎德盖大型金矿床位于北山造山带的黑鹰山弧内,含金石英脉主要赋存在早石炭世英云闪长岩内的裂隙或断裂中.流体成矿过程从早到晚划分为Ⅰ、Ⅱ、Ⅲ三个阶段,分别形成(磁铁矿)-黄铁矿-石英脉、石英-多金属硫化物脉和石英-方解石脉.本次研究通过矿相学观察、扫描电镜/能谱及电子探针分析,在该矿床Ⅱ阶段矿石样品中首次发现大量碲化物,该矿物系列主要产出在黄铁矿、石英中或其裂隙内.矿区已发现的碲化物包括碲金矿、斜方碲金矿、针碲金银矿、碲金银矿、碲银矿、碲铅矿、碲汞矿、碲铋矿等;金银矿物仅以碲化物的形成存在.Ⅰ阶段流体的硫逸度(logfS2=-11.1～-9.5)较高、碲逸度(logfTe2≤-12.8)较低,Ⅱ阶段流体显示低硫逸度(log/S2=-13.5～-10.2)、高碲逸度(logfTe2=-11.1 ～-7.8)特征.碲化物的发现揭示了矿床与深部幔源的紧密联系,但同时不能排除矿区英云闪长岩提供成矿物质的可能.%The Herzhedegai large-scale gold deposit is located in the Heiyingshan arc of the Beishan orogenic belt in Gansu Province.The auriferous quartz veins are mainly hosted in the faults/fractures of Early Carboniferous tonalite.The hydrothermal mineralization can be divided into three stages from early to late,namely,Ⅰ-,Ⅱ-and lⅢ-stage,which are characterized by (magnetite)-pyrite-quartz vein,auriferous quartz-polymetallic sulfide vein and quartz-carbonate vein,respectively.Based on optical microscope,scanning electron microscope analysis with energy dispersive spectroscopy (SEM + EDS) and electronprobe micro-analysis (EPMA),it was the first time that a large number of the tellurides were discovered in the Ⅱ-stage ore samples.These minerals mainly occur in pyrite and quartz or in their fractures,consisting of calaverite,krennerite,sylvanite,petzite,hessite,altaite,coloradoite,tellurobismuthite and so on.Up to now,the discovered Au-Ag minerals are only occurring as Au-and Ag-tellurides.In Ⅰ-stage of mineralization,the fluid system has relatively high sulfur fugacity (log/S2 =-11.1 ～-9.5) and low tellurium fugacity (logfTe2 ≤ -12.8);in Ⅱ-stage,the fluid system has relatively low sulfur fugacity (logfS2 =-13.5 ～-10.2) and high tellurium fugacity (logfTe2 =-11.1 ～-7.8).The discovery of the tellurides in the Herzhedegai gold deposit indicates its close relationship with the mantle,but the possible source of tonalite cannot be excluded.
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