Evolution of Hydrothermal Fluids at Daehwa Mo-W Deposit

대화 Mo-W 열수 맥상 광상의 유체 진화 특성

  • Jo, Jin Hee (Department of Earth and Environmental Sciences, Chungbuk National University) ;
  • Choi, Sang Hoon (Department of Earth and Environmental Sciences, Chungbuk National University)
  • 조진희 (충북대학교 지구환경과학과) ;
  • 최상훈 (충북대학교 지구환경과학과)
  • Received : 2013.02.09
  • Accepted : 2013.02.24
  • Published : 2013.02.28


The Daehwa Mo-W deposit is located within the Gyeonggi massif. Quartz and calcite vein mineralization occurred in the Precambrian gneiss and Jurassic granites. Three main types (Type I: liquid-rich $H_2O$ type, Type II: vapor-rich $H_2O$ type, Type III: $CO_2-H_2O$ type) of fluid inclusions were observed and are classified herein based on their phase relations at room temperature. Within ore shoots, type III fluid inclusions have been classified into four subtypes (type IIIa, IIIb, IIIc and IIId) based on their volume percent of aqueous and carbonaceous ($CO_2$) phase at room temperatures combined with their total homogenization behavior and homogenization behavior of $CO_2$ phase. Homogenization temperatures of primary type I fluid inclusions in the quartz range from $374^{\circ}C$ to $161^{\circ}C$ with salinities between 13.6 and 0.5 equiv. wt.% NaCl. Homogenization temperatures of primary type III fluid inclusions in quartz of main generation, are in the range of $303^{\circ}C$ to $251^{\circ}C$. Clathrate melting temperatures of the type III fluid inclusions were 7.3 to $9.5^{\circ}C$, corresponding to salinities of 5.2 to 1.0 equiv. wt. % NaCl. Melting and homogenization temperatures of $CO_2$ phase of type III fluid inclusions were -57.4 to $-56.6^{\circ}C$ and 29.0 to $30.8^{\circ}C$, respectively. Fluid inclusion data indicate a complex geochemical evolution of hydrothermal fluids. The Daehwa early hydrothermal system is characterized by $H_2O-CO_2$-NaCl fluid at about $400^{\circ}C$. The main mineralization occurred by $CO_2$ immiscibility at temperatures of about 300 to $250^{\circ}C$. At the late base-metal mineralization aqueous fluid formed by mixing with cooler and less saline meteoric groundwater.


Daehwa;Mo-W;fluid inclusion;$H_2O-CO_2$-NaCl;immiscibility


Supported by : 충북대학교


  1. Diamond, L.W. (1992) Stability of $CO_2$-clathrate + $CO_2$ liquid + $CO_2$ vapour + aqueous KCl-NaCl solutions: Experimental determination and application to salinity estimates of fluid inclusions. Geochimica et Cosmochimica Acta, v.56, p.273-280.
  2. Haynes, F.M. (1985) Determination of fluid inclusion compositions by sequential freezing. Economic Geology. v.80, p.1436-1439.
  3. Hedenquist, J.W. and Henley, R.W. (1985) The importance of $CO_2$ on freezing point measurements for epithermal ore deposition. Economic Geology, v.80, p.1379-1406.
  4. Hendel, E.M. and Hollister, L.S. (1981) An empirical empirical solvus for $CO_2$-$H_2O$-2.6 wt.% salt. Geochimica et Cosmochimica Acta, v.45, p.225-228.
  5. KORES (2010) The detailed geological survey report (Molybden : Yeonil area, Moggye area)(Uranium : Miwon area). Seoul, p.64.
  6. Kennedy, G.C. (1954) Pressure-volume-temperature relations in $CO_2$ at elevated temperatures and pressures. American Journal of Science, v.252, p.225-241.
  7. Park, H.I. and Choi, S.W. (1974) A Study on the Fluid Inclusions in the Minerals from the Dae Hwa Tungsten-molybdenum Deposits, Jour. Korean Inst. Mining Geol. v.7, p.63-78.
  8. Park, H.I., Choi, S.W. and Kim, D.R. (1985) Fluid Inclusions of Daehwa and Donsan Tungsten-Molybdenum Deposits, Jour. Korean Inst. Mining Geol, v.18, p.225-237.
  9. Park, B.S. and Yeo, S.C. (1971) Explanatory Text of The Geological Map of Moggye Sheet. Geological Survey of Korea.
  10. Potter, R.W., Clynne, M.A. and Brown, D.L. (1978) Freezing point depression of aqueous sodium chloride solutions. Economic Geology, v.73, p.284-285.
  11. Shepherd, T.J., Rankin, A.H. and Alderton, D.H.M. (1985) A practical guide to fluid inclusion studies. Blackie, Glasgow, 239p.
  12. Shin, J.B. (1972) Daehwa, Deposits of Korea, Korea Mining Promotion Corporation, v.4, p.254-258.
  13. So, C.S., Kelvin L. Sheltom, David E. Seidemann and Brian J. Skinner (1983) The Dae Hwa Tungsten-Molybdenum mine, Republic of Korea: A geochemical study. Economic Geology, v.78, p.920-930.
  14. Span, R. and Wagner, W. (1996) A new equation of state for carbon dioxide covering the fluid region from the triple-point temperature to 1100 K at presures up to 800 MPa. Journal of Physical Chemistry Reference Data, v.35, p.1509-1596.
  15. Bodnar, R.J. (1983) A method of calculating fluid inclusion volumes based on vapor bubble diameters and P-V-TW properties of inclusion fluids. Economic Geology, v.78, p.535-543.
  16. Burruss, R.C. (1981) Analysis of phase equilibria in C-O-H-S fluid inclusions. In : Hollister, L.S. & Crawford, M.L., (eds.). Fluid Inclusions: Application to Petrology. Mineralogy Assocication of Canada Short Course Handbook, v.6, p.39-74.
  17. Todheide, K. and Frank, E.U. (1963) Das zwei-phasengebeit und die kritische kurve in sysstem kohlendioxid-wasser bis zu drucken von 3500 bar. Z. Phys. Chem. N. F., v.37, p.388-401.

Cited by

  1. A Study on the Characteristics of W-Mo Ore Deposit in Bayan-Onjuul, Mongolia Using Magnetic Data vol.17, pp.4, 2014,