青海共和牦牛沟铜金矿床地质特征及找矿标志

Geological Characteristics and Prospecting Indicator of the Maoniugou Cu-Au Deposit in Gonghe County,Qinghai Province

牦牛沟铜金矿地处鄂拉山成矿带,是以铜金为主的矽卡岩型多金属矿床。矿区内已发现的3条铜金矿体产于矽卡岩内外接触带,赋存于三叠系中统古浪堤组中段地层中,容矿岩石主要为矽卡岩和大理岩,围岩蚀变为硅化、矽卡岩化、黄铜矿化、黄铁矿化、磁黄铁矿化等。土壤地球化学测量和激电中梯测量成果解译分析表明:AP_3土壤异常(元素组合为Au-AS-Sb-Hg、Cu-Pb-ZnAg、W-Bi-Mo)与激电中梯DHJ_2低阻高极化异常为区内重要的物化探找矿标志,异常套合性好,沿矽卡岩呈带状分布;AP_3综合异常与DHJ_2极化异常套合区、DHJ_3异常高极化中心、AP_3综合异常高值区以及分布于矽卡岩两侧的AP_4、AP_5综合异常区为矿化富集区,建议对该类矿化富集区进一步开展工程验证,有望实现找矿突破。

Maoniugou Cu-Au deposit is located in Elashan metallogenic belt,which is belongs to skarn type Cu-Au deposit.The founded three Cu-Au ore-bodies are mainly situated in or out of the contact zone of the skarn and occurred in middle stratum of Middle Triassic Gulangdi Formation.The ore-hosted rock is is skarn and marble.The wall rock alteration includes silication,skarnization,chalcopyrite,pyritization,magnetic pyritization,etc.The interpretation and analysis results of the soil geochemical survey and induced polarization intermediate gradient survey show that：AP3anomaly（element combination are AuAS-Sb-Hg,Cu-Pb-Zn-Ag and W-Bi-Mo）and DHJ2low resistance and high polarization anomaly are the the important physic-chemical prospecting indicators of the mining area,which are in good nested and zonal distributed along the skarn belt;the nested area of AP3comprehensive anomaly and DHJ2polarization anomaly,DHJ3high polarization center,AP3comprehensive abnormal high value area and the AP4and AP5comprehensive anomaly areas distributed at the both sides of skarn can be taken as the mineralization enrichment areas in the mining area.It is suggested that some related engineering verification work can be conducted in this mineralization enrichment areas,and the prospecting breakthrough will be realized.