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2007 Vol.44, Issue 1 Preview Page
28 February 2007. pp. 20-27
Abstract
The Yuryang gold deposit is located in Cheonan area, Chungcheongnamdo province. It is hosted in Precambrian gneiss and is spatially related to pegmatite. The quartz veins display massive textures with weak potassic alteration. The ore mineralization is simple, with a low Ag/Au ratio of 1.5 : 1, due to the rarity of Ag-bearing minerals. Ore mineralization took place in two stages. The early Fe-sulfide mineralization occurred along the vein margins, and the late Au-Te-Bi mineralization is characterized by fracture fillings of galena, sphalerite, pyrrhotite, Te-Bi-bearing minerals. Fluid inclusions in vein quartz characteristically contain CO2 and can be classified into four types (Ia, Ib, IVa and IVb) according to the phase behavior. The results of fluid inclusion data indicate that the ore deposit was formed at a distinctively high temperature from fluids with moderate to low salinity (< 12 wt. % eq. NaCl) and CH4 (1~22 mole %). The dominant ore-deposition mechanisms were CO2 effervescence which triggered gold mineralization. The physicochemical conditions of the Yuryang gold deposit indicate that the Yuryang gold deposit may be an orogenic gold deposits with Te-Bi mineralization at a considerable depth.
유량 금광상은 충남 천안지역의 선캠브리아기 편마암내 배태되어 있고 페그마타이트와 밀접하게 관련되어 있다. 석영맥의 조직은 괴상이며 맥주변에는 약한 열수변질작용을 보인다. 광석광물의 종류는 단순하며, 은을 함유하고 있는 광물상의 부재로 낮은 은/금 비율을 나타낸다. 광화작용은 2회에 걸쳐 진행되었으며, 초기 광화작용의 철-황화광물은 전형적으로 맥주변에서 산출하며, 후기의 금-텔루륨-비스무스 광화작용에는 방연석, 섬아연석, 자류철석, 텔루륨함유 광물, 에렉트럼등의 광물이 열극을 충진하는 특징을 보인다. 유체포유물은 특징적으로 이산화탄소를 함유하며 상변화에 따라 4개 유형(Ia, Ib, IVa 및 IVb)으로 구분된다. 유체포유물 자료에 의하면 본 광상이 저 내지 중염농도(< 12 wt. % eq. NaCl)와 메탄(1~22 mole %)을 함유한 광화유체로부터 고온에서 생성되었음을 지시한다. 광화유체로부터 금의 침전 메카니즘은 이산화탄소 불혼화작용에 기인된다. 유량 금광상에서 관찰된 물리·화학적 조건들을 고려하면 본 광상이 상당한 심도에서 텔루륨-비스무스 광화작용을 수반하는 조산성 금광상과 유사한 것으로 사료된다.
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Information
  • Publisher :The Korean Society of Mineral and Energy Resources Engineers
  • Publisher(Ko) :한국자원공학회
  • Journal Title :Journal of the Korean Society for Geosystem Engineering
  • Journal Title(Ko) :한국지구시스템공학회지
  • Volume : 44
  • No :1
  • Pages :20-27