전남(全南) 옥매산광상(玉埋山鑛床)의 열수변질작용(熱水變質作用) 및 광석광물(鑛石鑛物)에 대한 광물학적(鑛物學的) 연구

Hydrothermal Alteration and Mineralogy of Alunite and Kaolinite in the Ogmae Deposit, Southwest Jeonnam

  • 김영희 (연세대학교 지질학과) ;
  • 문희수 (연세대학교 지질학과) ;
  • 김종환 (한국동력자원연구소, 비금속광상연구실) ;
  • 유장한 (한국동력자원연구소, 비금속광상연구실) ;
  • 김인준 (동경대학교)
  • Kim, Young Hee (Dept. of Geology, Yonsei University) ;
  • Moon, Hi-Soo (Dept. of Geology, Yonsei University) ;
  • Kim, Jong Hwan (Non-metallic Min. Section., Korea Institute of Energy and Resources) ;
  • You, Jang Han (Non-metallic Min. Section., Korea Institute of Energy and Resources) ;
  • Kim, In Joon (Dept. of Geology, Faculty of Science, The University of Tokyo)
  • 발행 : 1990.06.30

초록

The Ogmae alunite-kaolinite deposit occurs in acidic tuff, the Hwangsan Tuff, of upper Crataceous age in the Haenam volcanic field, SW Jeonnam. This deposit characterized by advanced argillic alteration formed $71.8{\pm}2.8{\sim}73.9{\pm}2.8$ Ma ago in very shallow depth environment with acid-sulfate solution. Wallrock alteration can be classified into four zones from the center to the margin of the deposit: alunite, kaolinite, illite, and silicified zone. The mineral assemblage in the alunite zone, ore zone, is alunite-quartz-pyritekaolinite. Consideration of stability relation of these minerals suggests that the maximum alteration temperature is estimated at about $250^{\circ}C$ with solution pH of 3 or below assuming that pressure does not exceed 0.3 Kb. Alunite occurs as two different types; replacement and vein-type deposit. The former one consists of fine grained alunite and the later one coarse grained and relatively pure alunite that formed by open space filling. Isomorphous substitution of Na for K in these two types of alunites range 0 to 40 %, indicating that Na/K ratio in the solution is spontaneously changed during the alteration process. Alunite which has higher Na substitution probably formed in an earlier stage while the solution sustain high Na/K ratio. K-Ar age of alunites indicate that the replacement alunite formed earlier($73.9{\pm}2.8Ma$) than the vein-type alunite($71.8{\pm}2.8Ma$). The ${\delta}^{34}S$ value of pyrite and alunite indicate that those minerals formed at isotopically nonequillibrium state. The ${\delta}^{16}O$ and ${\delta}D$ values, of kaolintics 5.0 to 9.0‰ and -54 to -99‰, respectively, indicate that those are formed by hydrothermal solution having magmatic origin which have been diluted by low ${\delta}D$ meteoric water.

키워드

과제정보

연구 과제번호 : 해남지역 납석 및 고령토 광물자원 연구

연구 과제 주관 기관 : 과학재단