Endoskarn and Cu-Zn mineralization at the Empire mine, Idaho, USA

摘要: The Empire mine is a Cu-Zn skam associated with the granite porphyry phase of Mackay Stock, which consists quartz monzodiorite, granophyre, porphyry, Granite, and numerous dikes. Both Granite have high F also unusual, extremely vermicular phenocrysts. endoskarn exoskam are developed at mine, more endoskam than exoskarn. alteration intrusive rocks began weak disseminated diopsidic pyroxene, actinolite, titanite. Further formed by veins or as massive replacements rocks. earliest veinlets contain scapolite, without wollastonite halo. This was followed wollastonite-dominant (± Carich plagioclas hedenbergitic pyroxene) fronts envelopes on garnet-dominant veins. Early pyroxene whereas in distal/late hedenbergitic. Similarly, garnet becomes Fe-rich time. In exoskam, all andraditic. Magnetite precipitated after garnet-pyroxene both exoskam. Zn sulfide together Cu proximal locations, retrograde quartz+calcite+chlorite. Massive exoskarn replacement 500–550°C, slightly higher temperatures were recorded late minerals metasomatic front, >600°C. highest temperatures, >700°C, occur gamet-dominant that probably represent conduits insulated earlier skarn. During alteration, quartz, calcite, chlorite, fluorite, chalcopyrite 250–300°C. texture phenocrysts, abundant endoskarn, deposition Zn, caused contents magma magmatic fluid.