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爱达荷钴矿带的 Cu-Co-Au 矿床产在中元古代耶洛贾克特组(Yellowjacket F.)中,该组以含有独特的化学和矿物成分,包括高浓度 Fe(15—30wt%Fe_2O_3)、Cl(0.1—1.10wt%)和磁铁矿或黑云母(>50vol%)为特征。黑鸟(Black-bird)矿区的 Cu-Co-Au矿床是产在 Fe 硅酸盐相岩层中的层控矿床,该硅酸盐相岩层富含 Fe、黑云母和 Cl。下部岩石地层带含有磁铁矿和小型 Cu-Co-Au 矿床,其延伸大于40km。富铁岩层可能是与镁铁质火山作用和海底热泉有关的喷气岩单位,但对高 Cl 浓度的成因不清楚。认为富 Cl 的孔隙流体是由于存在超盐度液体包体、富 Cl 黑云母和方柱石(Scapolite)(相当富 Fe 黑
The Cu-Co-Au deposit in the Idaho Cobalt Belt is produced in the Mesoproterozoic Yellowjacket F. The group contains unique chemical and mineral constituents including high concentrations of Fe (15-30 wt % Fe 2 O 3), Cl (0.1-1.10 wt%) and magnetite or biotite (> 50 vol%). The Cu-Co-Au deposit in the Black-Bird deposit is a stratiformic deposit hosted in a Fe-silicate facies that is rich in Fe, biotite and Cl. The lower lithostratigraphic zone contains magnetite and small Cu-Co-Au deposits that extend more than 40 km. The iron-bearing rock formation is probably a jet-rock unit related to mafic volcanism and seafloor thermal springs, but the cause of the high Cl concentration is unclear. Cl-rich pore fluids are believed to be due to the presence of over-salinity liquid inclusions, Cl-rich biotite and Scapolite (rather rich Fe black