云南大姚铜矿银的赋存状态与成矿地质特征

矿床产于白垩系上统长石石英砂岩中,为典型的砂岩型铜矿。对矿床的矿石物质成分,银、铜、金的赋存状态及分布规律和矿床成矿特征研究结果:该矿床的银矿物有辉银矿、自然银、硫铜银矿、硫砷铜银矿、硫铁铜银矿、角银矿、银辉铜矿和银砷黝铜矿8种,其中后5种为本次工作发现;与铜矿带相对应,矿体有银矿物相带,并发现两个不同成因的“高银带”——原生高银带与次生高银带;原生矿体中银的峰值位于铜峰值的东侧,两者相距80～120m,规律性显著;矿床成因类型为多次叠加的沉积热卤水改造矿床;指出了大雪山背斜东翼南部倾伏部位为矿区外围找矿远景区,并在已知铜矿床内提出了两个高银预测区。

OCCURRENCE AND GEOLOGIOAL CHARACTERISTICS OF SILVER IN DAYAO COPPER DEPOSIT, YUNNAN

The ore deposit occurs in feldspathic quartz sandstone in the Upper Cretaceous systemand is a typical sandstone-type copper one. It has shown from the research results on the orematerial constituents of the silver, copper and gold and mineralization characterisatics of thedeposit that the silver minerals in the deposit include argentite, silver, stromeyerite,pearceite, Ag-fukuchilite, chlorargyrite, Agchalcocite, and Ag-tennantite, among which thelatter 5 minerals being discovered througn this study. The ore bodies have the silver mineralfacies zone correspondign to the copper ore zone and two high slver zones of the differentori-gins- - the primary high silver zone and the secondary silver zone. The peak vaiue of silverin primary ore bodies is located on the castern side of the copper peak value, with the dis-tance being from 80 to 120 m between them and the regulations being obvions. The genetictype of the ore deposit belongs to that of multisuperimposed sedimentary-hot brine reworkeddeposits. It is pointed out that the southern plunging portion of the east ring of Daxueshananticline is a prospective area of the periphery of mine and there are two high silver prognos-tie parts within the scope of known copper deposits.