靑陽重石鑛床의 地質과 流體包有物에 依한 溫度測定에 關한 硏究

Geologic and fluid inclusion studies of Chongyang tungsten ore deposits, South Korea

Chongyang tungsten ore deposits, one of the most important tungsten mines in South Korea, are open space filling hydrothermal vein deposits embedded in Precambrian biotite gneiss and Cretaceous (?) granite porphyry. Some wolframito-bearing quartz veins are closely associated with quartz porphyries which strike about N15˚-25˚W and dip 80˚SE to vertical. Mineralization took place in near vertical vein systems of 5 to 2000 meter long in the biotite gneiss and granite porphyry stock during early Cretaceous and Tertiary (?) period. The hydrothermal mineral paragensis has indicated that there were two major stages: vein and vug stages. The principal vein mineral is wolframite in a gangue of quartz with small amount of fluorite, pyrite, beryl and carbonate minerals. Present in minor amounts are molybdenite, bithmuthinite, native bismuth, arsenopyrite, galena, chalcopyrite, pyrrhotite, sphalerite and scheelite. Fluid inclusion study from the minerls at Chongyang mine reveals that vein stage fluids attained a temperature range of 200℃-355℃ and vug stage 160℃-350℃. The filling temperatures show the higher range of 200˚-355℃ in quartz and 280℃-348℃ in beryls, whereas the lower - emperature range of 283℃-295℃ in rhodochrosite and 160˚-253℃ in fluorites. These temperatures are in reasonably good agreement with mineral paragnesis in this ore deposits. Wolfamite minerals were analysed for major components, WO₃, MnO and FeO by wet chemical method. Chemical analysis indicates that they contain 70.56-71.54% WO₃, 8.52-10.01% MnO and 10.00-11.58% FeO. MnO/FeO ratios of wolframites shows the range of 0.78-0.94 which maybe indicates a comparatively high temperature type of hydrothermal deposits.