The Gold-Silver Mineralization of the Deogheun and Beopjeon Mines

덕흔·법전광산(法田鑛山)의 금(金)-은(銀)광화작용(鑛化作用)

Gold-silver deposits of Deogheun and Beopjeon mines are composed of veins emplaced in Jurassic granite batholith. Based on ore structure and ore mineralogy, four distinct stages of mineral deposition are recognized in these ore deposits. Gold and silver minerals in Deogheun and Beopjeon-A ore deposits are precipitated in stage III and stage II, respectively. Mineral constituents of ores from these deposits are pyrite, sphalerite, arsenopyrite, pyrrhotite, chalcopyrite, galena, tetrahedrite, electrum, quartz and rhodochrosite. Cubanite, argentite and pyrargyrite occur only in Deogheun ore deposits. Ag content of electrum range from 42 to 66 atomic % in both ore deposits. Filling temperature of fluid inclusion from both ore deposits are as follows; stage I, $211-289^{\circ}$ ; stage II, $205-290^{\circ}$ ; stage III, $190-260^{\circ}$ ; stage IV, $136-222^{\circ}$ in Deogheun ore deposits. In Beopjeon-A ore deposits, stage I, $255-305^{\circ}$ ; stage II, $135-222^{\circ}$ ; stage III, $148-256^{\circ}$ ; stage IV, $103-134^{\circ}$. Salinities of fluid inclusions range from 1.6-8.5 wt. % equivalent NaCl in both ore deposits. Sulfur fugacities through stage II and III in Deogheun ore deposits inferred from data of mineral assemblage and fluid inclusion range from $10^{-11.0}-10^{-16.1}$1bars. Fluid pressure estimated from fluid inclusions which reveal boiling evidence range from 30-190 bars during mineralization in Deogheun ore deposits.