Fluid Inclusion Study of a Magmatic Cobalt Mineralization at the Boguk Mine, Korea

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2006 Vol.43, Issue 2 Preview Page Next Page

Fluid Inclusion Study of a Magmatic Cobalt Mineralization at the Boguk Mine, Korea 보국 마그마성 열수 코발트 광화작용의 유체포유물연구: 허철호, 이재호, 윤성택, 소칠섭
Chul-Ho Heo, Jae-Ho Lee, Seong-Taek Yun and Chil-Sup So

30 April 2006. pp. 106-117

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Abstract

Hydrothermal quartz carbonates actinolite veins of the Boguk cobalt mine filled the fractures in a granite stock of Late Cretaceous age. They show the polymetallic nature consisting of Co-, Mo-, Cu-, Pb-, Zn-, Bi-, and Au-bearing ore minerals, and is divided into five stages. The vein mineralogy changes systematically with time: cobalt-bearing, arsenides and sulfarsenides and molybdenite with actinolite and quartz → base-metal sulfides, gold,and Fe oxides → barren carbonates. Equilibrium thermodynamic considerations of ore mineral assemblages are as follows: cobalt mineralization in stages I and II, T = 560-360℃, log fs2 = -6.2 to -12.0 atm deposition of base-metal sulfides and gold in stage III, T = 380-275℃, log fs2 = -7.5 to -10.6 atm. With the transition from cobalt mineralization toward base-metal sulfide deposition occurred the temperature decrease and concomitant increase in fo2. The deposition of cobalt probably occurred as a result of cooling and reduction of the magmatic brines. This cooling and dilution occurred by mixing with progressively larger volumes of meteoric groundwater as an early magmatic system waned, and resulted in successive deposition of base-metal sulfides, gold and bismuth, Fe oxides, and carbonates. By combining the mineralogic, fluid inclusion and petrochemical data, the following model is proposed for ore genesis at Boguk: during the Late Cretaceous, a micrographic granite stock intruded volcanosedimentary rocks at near surface. Cobalt, arsenic, and molybdenum were partitioned into high-temperature (up to ~585℃), high-salinity (up to 67 wt. % NaCl) magmatic brines exsolved directly from the crystallizing magma. As the magmatic brine cooled, these metals precipitated as arsenides and sulfarsenides in quartz actinolite veins. Following the waning of the magmatic hydrothermal system at temperatures around 350℃, a huge circulation of meteoric groundwater formed to collapse the system, resulting in progressively larger degrees of cooling, dilution and oxidation of hydrothermal fluids. Base metals, gold, and possibly calcium were leached from surrounding sedimentary rocks during the meteoric water circulation, and formed the fluids related tostage III to V mineralization.

Keywords

Cobalt deposit

Mineralogy

Fluid inclusion

보국 코발트 광산의 열수성 석영 ± 탄산염 ± 녹섬석 맥들은 백악기 후기의 화강암내 열극을 충진했다. 맥의 광물조성은 코발트, 몰리브덴, 구리, 납, 아연, 비스무스 및 금의 광석광물을 함유하고 있는 다금속 성향을 보이며, 광화작용은 5개의 광화시기로 구분된다. 맥상광물은 광화시기에 따라 체계적으로 변화하며 다음과 같은 광물공생군을 보인다: 녹섬석과 석영을 수반한 함코발트 비화물, 유비화물 및 휘수연석 → 천금속 황화물, 금, 철산화물 → 탄산염. 광석광물공생에 대해 평형 열역학을 적용하면 다음과 같다: 광화 1, 2기 코발트 광화작용은 T = 560-360℃, log fs2 = -6.2~-12.0 atm의 광화유체에서 일어났으며, 광화 3기의 천금속 황화물 및 금은 T = 380-275℃, log fs2 = -7.5~-10.6 atm 유체에서 침전되었다. 코발트 광화작용에서 천금속 황화물 침전으로 광화작용이 진행되면서 온도감소와 산소분압의 증가가 수반되었을 것으로 사료된다. 코발트의 침전은 마그마성 염수의 냉각 및 환원에 의해 야기되었을 것으로 사료된다. 이 냉각 및 희석은 초기 마그마계가 쇠퇴하면서 다량의 천수성 지하수의 혼입에 의해서 발생했으며, 계속해서 천금속 황화물, 금, 비스무스가 침전되었다. 광물학 및 유체포유물연구에 의하면, 코발트, 비소, 몰리브덴은 마그마 정출작용중 직접 용리된 고온(<~585℃), 고염농도(<67 wt. NaCl)의 마그마 염수로부터 용리되어 분별된 것으로 사료된다. 마그마 염수가 냉각되면서, 이 금속들은 석영 ± 녹섬석맥내 비화물과 유비화물로 침전되었다. 약 350℃의 온도에서 마그마성 열수계가 쇠퇴하면서, 천수성 지하수의 거대순환이 마그마성 열수계를 붕괴시키고 점진적으로 열수유체의 냉각, 희석, 산화가 촉진된다. 첨금속, 금, 칼슘은 천수순환중 주변의 퇴적암에서 용탈되며 광화 3기에서 5기의 광화작용과 관련된 유체를 형성하게 된다.

키워드

물질흐름분석

자원관리

지속가능한

자원이용지수

References

Ahmad, S.N., and Rose, A.W., 1980, Fluid inclusions in porphyry and skarn ore at Santa Rita, New Mexico, Economic Geology, V. 75, p. 229-250.
Badham, J.P.N., 1975, Mineralogy, paragenesis and origin of the Ag-Ni, Co arsenide mineralization, Camsell River, N. W. T., Canada, Mineralium Deposita, v. 10, p. 153-175.
Badham, J.P.N., 1976, Orogenesis and metallogenesis with reference to the silver-nickel-cobalt-arsenide ore association, in Strong, D.F., ed., Metallogeny and Plate Tectonics, Geological Association of Canada, Special Paper, v. 14, p. 541-548.
Barton, P.B., Jr.,and Skinner, B.J., 1979, Sulfide mineral stabilities, in Barnes, H.L., ed., Geochemistry of Hydrothermal Ore Deposits (2nd ed.)., New York, Wiley Intersci., p. 278-403.
Barton, P.B., Jr., and Toulmin, P., III, 1964, The electrum tarnish method for determination of the fugacity of sulfur in laboratory sulfide systems: Geochimica et Cosmochimica Acta, v. 33, p. 841-857.
Bloom, M.S., 1981, Chemistry of inclusion fluids; stockwork molybdenum deposits from Questa, New Mexico, Hudson Bay Mountain, and Endako, British Columbia, Economic Geology, V. 76, p. 1906-1920.
Bodnar, R.J., 1993, Revised equation and table for determining the freezing point depression of H2O-NaCl solutions, Geochimica et Cosmochimica Acta, v. 57, p. 683-684.
Bodnar, R.J., Burnham, C.W., and Sterner, S.M., 1985, Synthetic fluid inclusions in natural guartz. III. Determination of equilibrium properties in the system H2ONaCl to 1000℃ and 1500 bars, Geochimica et Cosmochimica Acta, V. 49, p. 1861-1873.
Burnham, C.W., and Ohmoto, H., 1980, Late-stage processes of felsic magmatism, Mining Geology Special Issue (Japan), V. 8, p. 1-11.
Chou, I.M., 1987, Phase relations in the system NaCl-KCl-H2O. III: Solubilities of halite in vapor-saturated liquids above 445℃ and redetermination of phase equilibrium properties in the system NaCl-H2O to 1000℃ and 1500 bars, Geochimica et Cosmochimica Acta, v. 51, p. 1965-1975.
Cline, J.S., and Bodnar, R.J., 1994, Direct evolution of brine from a crystallizing silicic melt at the Questa, New Mexico, molybdenum deposit, Economic Geology, V. 89, p. 1780-1802.
Crerar, D.A., Wood, S., Brantly, S., and Bocarsly, A., 1985 Chemical controls on solubility of ore-forming minerals in hydrothermal solutions, Canadian Mineralogist, V. 23, p. 333-352.
Eastoe, C.J., 1978, A fluid inclusion study of the Panguna porphyry copper deposit, Bougainville, Papua New Guinea, Economic Geology, V. 73, p. 721-748.
Goodz, M.D., Watkinson, D.H., Smejkal, V., and Pertold Z., 1986,Sulfur-isotope geochemistry of the silver- sulfarsenide vein mineralization, Cobalt, Ontario, Canadian Journal of Earth Sciences, v. 23, p. 1551-1567.
Halls, C., and Stumpfl, E.F., 1972,The five-element (Ag- Bi-Co-Ni-As) vein deposits - A critical appraisal of the geological environments in which it occurs and of the theories affecting its origin [abs.]: 24th International Geological Congress, Montreal, Section 4, p. 540.
Henley, R.W., and McNabb, A., 1978, Magmatic vapor plumes and groundwater interaction in porphyry copper emplacement, Economic Geology, V. 73, p. 1-20.
Horrall, K.B., Hagni, R.D., and Kisvarsanyi, G., 1993, Mafic and ultramafic plutons associated with the New Madrid Rift Complex - A possible major source of the copper-cobalt-nickel mineralization of southeast Missouri, Economic Geology, V. 88, p. 328-343.
Kamilli, R.J., 1978, The genesis of stockwork molybdenite deposits: Implications from fluid inclusion studies at the Henderson mine [abs.], Geological Society of America Abstracts with Programs, V. 10, p. 431.
Kerrich, R., Strong, D.F., Andrews, A.J., and Owsiacki, L., 1986,The silver deposits at Cobalt and Gowganda, Ontario: III. Hydrothermal regimes and source reservoirs-evidence from H, O, D, and Sr isotopes and fluid inclusions, Canadian Journal of Earth Sciences, V. 23, p. 1519-1550.
Kissin, S.A., 1988, Nickel-cobalt-native silver (fiveelement) veins: A rift-related ore type, in Kisvarsanyi, G., and Grant, S.K., eds., Proceedings of North American Conference on Tectonic Control of Ore Deposits and the Vertical and Horizontal Extent of Ore Systems. Univ. Missouri-Rolla, Rolla, p. 268-279.
Kissin, S.A., 1993, The geochemistry of transport and deposition in the formation of five-element (Ag-Ni-Co--As-Bi) veins, in Maurice, Y.T., ed., Proceedings of the Eighth Quadrennial IAGOD Symposium, Stuttgart, E. Schweizerbart'sche Verlagsbuchhandlung, p. 773-786.
Kretschmar, U., and Scott, S.D., 1976, Phase relations involving arsenopyrite in the system Fe-As-S and their application, Canadian Mineralogist, v. 14, p. 364-386.
Krutov, G.A., 1977, Deposits of cobalt, inSmirnov, V.I., ed., Ore Deposits of the USSR, London, Pitman Publishing, V. 2, p. 80-105.
Nakamura, K., 1942, A report of Korean cobalt mine, Journal of Geology (Japan), V. 49, p. 218-220 (in Japanese).
Nakamura, Y., and Shima, H., 1982, Fe and Zn partitioning between sphalerite and stannite [abs.], Joint Meeting of Society of Mining Geologists of Japan, Japanese Association of Mineralogists, Petrologists and Economic Geologists, and Mineralogical Society of Japan, 1982, Abstracts, p. A-8.
Park, M.E., 1990, Mineralization and paragenesis of the cobalt-bearing sulfide and arsenide minerals in Gyeongsan area, Geological Society of Korea Journal, V. 26, p. 18-31 (in Korean).
Reynolds, T.J., and Beane, R.E., 1985, Evolution of hydrothermal fluid characteristics at the Santa Rita, New Mexico, porphyry copper deposit, Economic Geology, V. 80, p. 1328-1347.
Roedder, E., 1984, Fluid inclusions, Reviews in Mineralogy, V. 12, p. 644.
Samson, I.M., 1990, Fluid evolution and mineralization in a subvolcanic granitestock: The Mount Pleasant WMo-Sn deposits, New Brunswick, Canada, Economic Geology, V. 85, p. 145-163.
Scott, S.D., and Barnes, H.L., 1971, Sphalerite geothermometry and geobarometry, Economic Geology, v. 66, p. 653-669.
Schneider, H.J., 1972, Stratabound polymetallic and Fe-Ba deposits of the Sarrabus-Gerrei region, southeastern Sardinia: I. Mineral deposits and geology, Neues Jahrbuch fÜr Mineralogie Monatschafte, V. 12, p. 529-541(in German).
Shimizu, M., and Shikazono, N., 1985, Iron and zinc partitioning between coexisting stannite and sphalerite: A possible indicator of temperature and sulfur fugacity, Mineralium Deposita, v. 20, p. 314-320.
So, C.S., Shelton, K.L., Chi, S.J., and Yun, S.T., 1991, Geochemical studies of the Gyeongchang W-Mo mine, Republic of Korea: Progressive meteoric water inundation of a magmatic hydrothermal system, Economic Geology, V. 86, p. 750-767.
So, C.S., Choi, S.H., and Shelton, K.L, 1997, Geochemistry and genesis of hydrothermal Cu deposits in the Gyeongsang Basin (Andong area), Korea: A link between porphyry and epithermal systems, Neues Jahrbuch fÜr Mineralogie Abhandlungen, V. 171, p. 281-307.
Sourirajan, S., and Kennedy, G.C., 1962, The system H2ONaCl at elevated temperatures and pressures, American Journal of Science, V. 260, p. 115-141.
Sterner, S.M., Hall, D.L., and Bodnar, R.J., 1988, Synthetic fluid inclusions. V. Solubility of the system NaCl-KCl-H2O under vapor-saturated conditions, Geochimica et Cosmochimica Acta, v. 52, p. 989-1005.
Susak, N.J., and Crerar, D.A., 1985, Spectra and coordination changes of transition metals in hydrothermal solution: Implications for ore genesis, Geochimica et Cosmochimica Acta, V. 49, p. 555-564.
Uchida, E., Goryozono, Y., and Naito, M., 1996, Aqueous speciation of magnesium, strontium, nickel and cobalt chlorides in hydrothermal solutions at 600℃ and 1 kbar, Geochemical Journal, V. 30, p. 99-109.
Yun, S.T., and Youm, S.J., 1997, Temporal variations of ore mineralogy and sulfur isotope data from the Boguk cobalt mine: Implication for genesis and geochemistry of Co-bearing hydrothermal system, Economic and Environmental Geology (Korea), v. 30, p. 289-301.

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 : 43
No :2
Pages :106-117

[1] Ahmad, S.N., and Rose, A.W., 1980, Fluid inclusions in porphyry and skarn ore at Santa Rita, New Mexico, Economic Geology, V. 75, p. 229-250.

[2] Badham, J.P.N., 1975, Mineralogy, paragenesis and origin of the Ag-Ni, Co arsenide mineralization, Camsell River, N. W. T., Canada, Mineralium Deposita, v. 10, p. 153-175.

[3] Badham, J.P.N., 1976, Orogenesis and metallogenesis with reference to the silver-nickel-cobalt-arsenide ore association, in Strong, D.F., ed., Metallogeny and Plate Tectonics, Geological Association of Canada, Special Paper, v. 14, p. 541-548.

[4] Barton, P.B., Jr.,and Skinner, B.J., 1979, Sulfide mineral stabilities, in Barnes, H.L., ed., Geochemistry of Hydrothermal Ore Deposits (2nd ed.)., New York, Wiley Intersci., p. 278-403.

[5] Barton, P.B., Jr., and Toulmin, P., III, 1964, The electrum tarnish method for determination of the fugacity of sulfur in laboratory sulfide systems: Geochimica et Cosmochimica Acta, v. 33, p. 841-857.

[6] Bloom, M.S., 1981, Chemistry of inclusion fluids; stockwork molybdenum deposits from Questa, New Mexico, Hudson Bay Mountain, and Endako, British Columbia, Economic Geology, V. 76, p. 1906-1920.

[7] Bodnar, R.J., 1993, Revised equation and table for determining the freezing point depression of H2O-NaCl solutions, Geochimica et Cosmochimica Acta, v. 57, p. 683-684.

[8] Bodnar, R.J., Burnham, C.W., and Sterner, S.M., 1985, Synthetic fluid inclusions in natural guartz. III. Determination of equilibrium properties in the system H2ONaCl to 1000℃ and 1500 bars, Geochimica et Cosmochimica Acta, V. 49, p. 1861-1873.

[9] Burnham, C.W., and Ohmoto, H., 1980, Late-stage processes of felsic magmatism, Mining Geology Special Issue (Japan), V. 8, p. 1-11.

[10] Chou, I.M., 1987, Phase relations in the system NaCl-KCl-H2O. III: Solubilities of halite in vapor-saturated liquids above 445℃ and redetermination of phase equilibrium properties in the system NaCl-H2O to 1000℃ and 1500 bars, Geochimica et Cosmochimica Acta, v. 51, p. 1965-1975.

[11] Cline, J.S., and Bodnar, R.J., 1994, Direct evolution of brine from a crystallizing silicic melt at the Questa, New Mexico, molybdenum deposit, Economic Geology, V. 89, p. 1780-1802.

[12] Crerar, D.A., Wood, S., Brantly, S., and Bocarsly, A., 1985 Chemical controls on solubility of ore-forming minerals in hydrothermal solutions, Canadian Mineralogist, V. 23, p. 333-352.

[13] Eastoe, C.J., 1978, A fluid inclusion study of the Panguna porphyry copper deposit, Bougainville, Papua New Guinea, Economic Geology, V. 73, p. 721-748.

[14] Goodz, M.D., Watkinson, D.H., Smejkal, V., and Pertold Z., 1986,Sulfur-isotope geochemistry of the silver- sulfarsenide vein mineralization, Cobalt, Ontario, Canadian Journal of Earth Sciences, v. 23, p. 1551-1567.

[15] Halls, C., and Stumpfl, E.F., 1972,The five-element (Ag- Bi-Co-Ni-As) vein deposits - A critical appraisal of the geological environments in which it occurs and of the theories affecting its origin [abs.]: 24th International Geological Congress, Montreal, Section 4, p. 540.

[16] Henley, R.W., and McNabb, A., 1978, Magmatic vapor plumes and groundwater interaction in porphyry copper emplacement, Economic Geology, V. 73, p. 1-20.

[17] Horrall, K.B., Hagni, R.D., and Kisvarsanyi, G., 1993, Mafic and ultramafic plutons associated with the New Madrid Rift Complex - A possible major source of the copper-cobalt-nickel mineralization of southeast Missouri, Economic Geology, V. 88, p. 328-343.

[18] Kamilli, R.J., 1978, The genesis of stockwork molybdenite deposits: Implications from fluid inclusion studies at the Henderson mine [abs.], Geological Society of America Abstracts with Programs, V. 10, p. 431.

[19] Kerrich, R., Strong, D.F., Andrews, A.J., and Owsiacki, L., 1986,The silver deposits at Cobalt and Gowganda, Ontario: III. Hydrothermal regimes and source reservoirs-evidence from H, O, D, and Sr isotopes and fluid inclusions, Canadian Journal of Earth Sciences, V. 23, p. 1519-1550.

[20] Kissin, S.A., 1988, Nickel-cobalt-native silver (fiveelement) veins: A rift-related ore type, in Kisvarsanyi, G., and Grant, S.K., eds., Proceedings of North American Conference on Tectonic Control of Ore Deposits and the Vertical and Horizontal Extent of Ore Systems. Univ. Missouri-Rolla, Rolla, p. 268-279.

[21] Kissin, S.A., 1993, The geochemistry of transport and deposition in the formation of five-element (Ag-Ni-Co--As-Bi) veins, in Maurice, Y.T., ed., Proceedings of the Eighth Quadrennial IAGOD Symposium, Stuttgart, E. Schweizerbart'sche Verlagsbuchhandlung, p. 773-786.

[22] Kretschmar, U., and Scott, S.D., 1976, Phase relations involving arsenopyrite in the system Fe-As-S and their application, Canadian Mineralogist, v. 14, p. 364-386.

[23] Krutov, G.A., 1977, Deposits of cobalt, inSmirnov, V.I., ed., Ore Deposits of the USSR, London, Pitman Publishing, V. 2, p. 80-105.

[24] Nakamura, K., 1942, A report of Korean cobalt mine, Journal of Geology (Japan), V. 49, p. 218-220 (in Japanese).

[25] Nakamura, Y., and Shima, H., 1982, Fe and Zn partitioning between sphalerite and stannite [abs.], Joint Meeting of Society of Mining Geologists of Japan, Japanese Association of Mineralogists, Petrologists and Economic Geologists, and Mineralogical Society of Japan, 1982, Abstracts, p. A-8.

[26] Park, M.E., 1990, Mineralization and paragenesis of the cobalt-bearing sulfide and arsenide minerals in Gyeongsan area, Geological Society of Korea Journal, V. 26, p. 18-31 (in Korean).

[27] Reynolds, T.J., and Beane, R.E., 1985, Evolution of hydrothermal fluid characteristics at the Santa Rita, New Mexico, porphyry copper deposit, Economic Geology, V. 80, p. 1328-1347.

[28] Roedder, E., 1984, Fluid inclusions, Reviews in Mineralogy, V. 12, p. 644.

[29] Samson, I.M., 1990, Fluid evolution and mineralization in a subvolcanic granitestock: The Mount Pleasant WMo-Sn deposits, New Brunswick, Canada, Economic Geology, V. 85, p. 145-163.

[30] Scott, S.D., and Barnes, H.L., 1971, Sphalerite geothermometry and geobarometry, Economic Geology, v. 66, p. 653-669.

[31] Schneider, H.J., 1972, Stratabound polymetallic and Fe-Ba deposits of the Sarrabus-Gerrei region, southeastern Sardinia: I. Mineral deposits and geology, Neues Jahrbuch fÜr Mineralogie Monatschafte, V. 12, p. 529-541(in German).

[32] Shimizu, M., and Shikazono, N., 1985, Iron and zinc partitioning between coexisting stannite and sphalerite: A possible indicator of temperature and sulfur fugacity, Mineralium Deposita, v. 20, p. 314-320.

[33] So, C.S., Shelton, K.L., Chi, S.J., and Yun, S.T., 1991, Geochemical studies of the Gyeongchang W-Mo mine, Republic of Korea: Progressive meteoric water inundation of a magmatic hydrothermal system, Economic Geology, V. 86, p. 750-767.

[34] So, C.S., Choi, S.H., and Shelton, K.L, 1997, Geochemistry and genesis of hydrothermal Cu deposits in the Gyeongsang Basin (Andong area), Korea: A link between porphyry and epithermal systems, Neues Jahrbuch fÜr Mineralogie Abhandlungen, V. 171, p. 281-307.

[35] Sourirajan, S., and Kennedy, G.C., 1962, The system H2ONaCl at elevated temperatures and pressures, American Journal of Science, V. 260, p. 115-141.

[36] Sterner, S.M., Hall, D.L., and Bodnar, R.J., 1988, Synthetic fluid inclusions. V. Solubility of the system NaCl-KCl-H2O under vapor-saturated conditions, Geochimica et Cosmochimica Acta, v. 52, p. 989-1005.

[37] Susak, N.J., and Crerar, D.A., 1985, Spectra and coordination changes of transition metals in hydrothermal solution: Implications for ore genesis, Geochimica et Cosmochimica Acta, V. 49, p. 555-564.

[38] Uchida, E., Goryozono, Y., and Naito, M., 1996, Aqueous speciation of magnesium, strontium, nickel and cobalt chlorides in hydrothermal solutions at 600℃ and 1 kbar, Geochemical Journal, V. 30, p. 99-109.

[39] Yun, S.T., and Youm, S.J., 1997, Temporal variations of ore mineralogy and sulfur isotope data from the Boguk cobalt mine: Implication for genesis and geochemistry of Co-bearing hydrothermal system, Economic and Environmental Geology (Korea), v. 30, p. 289-301.

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