摘要
The Wadi Sharis orogenic gold deposit in northwestern Yemen is related to the fault and shear zones vein at medium depth in the crust in the Neoproterozoic meta-sedimentary and meta-volcanosedimentary succession of greenschist to amphibolite facies metamorphism.Three distinct fluid inclusion types have been identified in the gold-bearing quartz sulphide veins of the deposit:(1) type I:vapour-liquid two-phase(VH2O-LH2O),(2) type II:three-phase CO2(VCO2-LH2O-LCO2) and(3) type III:vapour-rich(LCO2-VCO2) inclusions.Six analysis of individual fluid inclusion indicate the fluid inclusions comprise mainly of H2O and CO2.Formation P-T conditions recorded by fluid inclusions in quartz crystals correspond to 180℃-380℃ and up to 130 MPa,as indicated by high-density CO2 bubbles(up to 0.98 g/cm3) observed in some inclusions.The estimated crystallization pressures correspond to approximately 4-10 km of overburden,assuming a lithostatic load.The salinity ranges from 0 to 22 wt%.The deposit holds at 0.2-5 g/t Au and contains low-moderate salinity.
The Wadi Sharis orogenic gold deposit in northwestern Yemen is related to the fault and shear zones vein at medium depth in the crust in the Neoprotcrozoic meta-sedimentary and meta-volcanosedimentary succes- sion of greenschist to amphibolite facies metamorphism. Three distinct fluid inclusion types have been identified in the gold-bearing quartz sulphide veins of the deposit： （1） type I： vapour-liquid two-phase （VH2O-LH2O ）, （2） type II ： three-phase CO2 （ VCO2 - LH2O - LCO2 ） and （3） type III： vapour-rich （LCO2 - VCO2 ） inclusions. Six analysis of individual fluid inclusion indicate the fluid inclusions comprise mainly of H2O and CO2. Forma- tion P-T conditions recorded by fluid inclusions in quartz crystals correspond to 180℃-380℃ and up to 130 MPa, as indicated by high-density CO2 bubbles （up to 0. 98 g/cm3 ） observed in some inclusions. The esti- mated crystallization pressures correspond to approximately 4-10 km of overburden, assuming a lithostatic load. The salinity ranges from 0 to 22 wt%. The deposit holds at 0.2-5 g/t Au and contains low-moderate salinity.
