沃川帶의 地質 및 鑛物資源에 關한 硏究

Studies on geology and mineral resources of the Okcheon belts -mineralization in the vicinity of the Muamsa granite stock-

Hundred mineral deposits including W-Mo, Pb-Zn-Cu, fluorite and talc occur in the Cambro-Ordovician limestone contacting with the Cretaceous Muamsa and Wolak granitoids in the Susanri-Hwanggangri mineralized zone. In most mineral deposits characterized by metasomatic replacement, skarn and hydrothermal vein types, two distinct tendencies were found as W-Mo mineralization in or/and near granitoid batholith and Pb-Zn-Cu(CaF₂) mineralization which is gradually increased toward the batholith. W-Mo veins of extensive vein system occupy northly striking fractures whilst Pb-Zn-Cu-CaF₂ veins strike northeast or northwest. In this work, three representative lead-zinc-copper deposits choosing the Dangdu, Useog and Boksu mines were dealt with in detail. Skarn ore bodies in the Dangdu mine were grouped into early diopside rich clinopyoxene-garnet, barren skarn and ore bearing late hedenbergite rich clinopyroxene-garnet skarn. Temperature and Xco₂ obtained from hedenbergite-andradite-calcite-quartz mineral equilibria in the Dangdu ore deposits were 580~650℃ and 0.15~0.3, respectively. Fluid inclusion evidence in the Useog mine indicates that main stage mineralization temperature ranges from 224 to 389℃ with a salinity ot 2~17 equivalent wt. percent NaCl. Sphalerites from the Dangdu and Useog mines have 16~17.7 mole percent in FeS which is relatively consistent to those of some other lead-zinc ore deposits in South Korea. Filling temperature of fluid inclusion from the Boksu mine shows deposition of ore within the temperature ranges from 237 to 347℃ and within the salinity ranges from 2.6 to 10.77 equivalent wt. percent NaCl.