Element Dispersion and Wallrock Alteration from Samgwang Deposit

삼광광상의 모암변질과 원소분산

  • Yoo, Bong-Chul (Department of Geology and Environmental Sciences, Chungnam National University) ;
  • Lee, Gil-Jae (Domestic & North Korea Mineral Resources Department, Korea Institute of Geoscience and Mineral Resources) ;
  • Lee, Jong-Kil (Metals Exploration Team, Exploration Department, Korea Resources Corporation) ;
  • Ji, Eun-Kyung (Department of Geology and Environmental Sciences, Chungnam National University) ;
  • Lee, Hyun-Koo (Department of Geology and Environmental Sciences, Chungnam National University)
  • 유봉철 (충남대학교 자연과학대학 지질환경과학과) ;
  • 이길재 (한국지질자원연구원 국내/북한자원연구실) ;
  • 이종길 (한국광물자원공사 탐사지원팀) ;
  • 지윤경 (충남대학교 자연과학대학 지질환경과학과) ;
  • 이현구 (충남대학교 자연과학대학 지질환경과학과)
  • Published : 2009.06.28

Abstract

The Samgwang deposit consists of eight massive mesothermal quartz veins that filled NE and NW-striking fractures along fault zones in Precambrian granitic gneiss of the Gyeonggi massif. The mineralogy and paragenesis of the veins allow two separate discrete mineralization episodes(stage I=quartz and calcite stage, stage II-calcite stage) to be recognized, temporally separated by a major faulting event. The ore minerals are contained within quartz and calcite associated with fracturing and healing of veins that occurred during both mineralization episodes. The hydrothermal alteration of stage I is sericitization, chloritization, carbonitization, pyritization, silicification and argillization. Sericitic zone occurs near and at quartz vein and include mainly sericite, quartz, and minor illite, carbonates and chlorite. Chloritic zone occurs far from quartz vein and is composed of mainly chlorite, quartz and minor sericite, carbonates and epidote. Fe/(Fe+Mg) ratios of sericite and chlorite range 0.45 to 0.50(0.48$\pm$0.02) and 0.74 to 0.81(0.77$\pm$0.03), and belong to muscovite-petzite series and brunsvigite, respectiveIy. Calculated $Al_{IV}$-FE/(FE+Mg) diagrams of sericite and chlorite suggest that this can be a reliable indicator of alteration temperature in Au-Ag deposits. Calculated activities of chlorite end member are $a3(Fe_5Al_2Si_3O_{10}(OH)_6$=0.0275${\sim}$0.0413, $a2(Mg_5Al_2Si_3O_{10}(OH)_6$=1.18E-10${\sim}$7.79E-7, $a1(Mg_6Si_4O_{10}(OH)_6$=4.92E-10${\sim}$9.29E-7. It suggest that chlorite from the Samgwang deposit is iron-rich chlorite formed due to decreasing temperature from high temperature(T>450$^{\circ}C$). Calculated ${\alpha}Na^+$, ${\alpha}K^+$, ${\alpha}Ca^{2+}$, ${\alpha}Mg^{2+}$ and pH values during wallrock alteration are 0.0476($400^{\circ}C$), 0.0863($350^{\circ}C$), 0.0154($400^{\circ}C$), 0.0231($350^{\circ}C$), 2.42E-11($400^{\circ}C$), 7.07E-10($350^{\circ}C$), 1.59E-12($400^{\circ}C$), 1.77E-11($350^{\circ}C$), 5.4${\sim}$6.4($400^{\circ}C$), 5.3${\sim}$5.7($350^{\circ}C$)respectively. Gain elements(enrichment elements) during wallrock alteration are $TiO_2$, $Fe_2O_3(T)$,CaO, MnO, MgO, As, Ag, Cu, Zn, Ni, Co, W, V, Br, Cs, Rb, Sc, Bi, Nb, Sb, Se, Sn and Lu. Elements(Ag, As, Zn, Sc, Sb, Rb, S, $CO_2$) represents a potential tools for exploration in mesothermal and epithermal gold-silver deposits.

Keywords

Samgwang deposit;wallrock alteration;element dispersion;pathfinder

References

  1. Helgeson, H.C. (1969) Thermodynamics of hydrothermal systems at elevated temperatures and pressures. American Journal of Science, v. 267, p. 729-804 https://doi.org/10.2475/ajs.267.7.729
  2. Helgeson, H.C. and Kirkham, D.H. (1978) Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures. II. Debye-Huckel parameters for activity coefficients and relative partial molal properties. American Journal of Science, v. 274, p. 1199-1261 https://doi.org/10.2475/ajs.274.10.1199
  3. Lee, H.K., Yoo, B.C., Hong, D.P. and Kim, K.W. (1995) Structural constraints on gold-silver-bearing quartz mineralization in strike-slip fault system, Samkwang mine, Korea. Economic and Environmental Geology, v. 28, p. 579-585
  4. Park, S.J., Choi, S.G. and Lee, D.E. (2003) The genetic implication of hydrothermal alteration of epithermal deposits from the Mugeuk area. Journal of Mineralogical Society of Korea. v. 16, p. 265-280
  5. Yang, D.Y. (1991) Mineralogy, petrology and geochemistry of the magnesian skarn-type magnetite deposits at the Shinyemi mine, Republic of Korea. Ph.D. thesis, Waseda University, 323p
  6. Berman, R.G. (1988) Internally-consistent thermodynamic data for minerals in the system $Na_2O-K_2O-CaOMgO-FeO-Fe_2O_3-Al_2O_3-SiO_2-TiO_2-H_2O-CO_2$. Journal of Petrology, v. 29, p. 445-522 https://doi.org/10.1093/petrology/29.2.445
  7. Kim, S.S., Choi, S.G., Choi, S.H. and Lee, I.W. (2002) Hydrothermal alteration and its genetic implication in the Gasado volcanic-hosted epithermal gold-silver deposit: Use in exploration. Journal of Mineralogical Society of Korea. v. 15, p. 205-220
  8. Lee, C.H. (1993) Geology, mineralogy, fluid inclusion and stable isotope of gold, silver and antimony ore deposits of the Dunjeon-Baegjon area, northern Taebaegsan mningdistrict, Korea. Ph.D. thesis, Seoul National University, 422p
  9. Um, S.H. and Lee, M.S. (1963) Geological map of Taehung sheet. Geological Survey of Korea
  10. Robert, F., Poulsen, K.H. and Dube, B. (1997) Gold deposits and their geological classification. Exploration 97, April 1997, Toronto, Canada, p. 209-219
  11. Yoo, B.C., Lee, H.K. and Kim, S.J. (2003) Stable isotope and fluid inclusion studies of the Daebong gold-silver deposits, Republic of Korea. Economic and Environmental Geology, v. 36, p. 391-405
  12. Jiang, W.T., Peacor, D.R. and Buseck, P.R. (1994) Chlorite geothermometry-contamination and apparent octahedral vacancies. Clays and Clay Minerals, v. 42, p. 593-605 https://doi.org/10.1346/CCMN.1994.0420512
  13. Shelton, K.L., So, S.C. and Chang, J.S. (1988) Gold-rich mesothermal vein deposits of the Republic of Korea: Geochemical studies of the Jungwon gold area. Economic Geology, v. 83, p. 1221-1237 https://doi.org/10.2113/gsecongeo.83.6.1221
  14. Kranidiotis, P. and MacLean, W.H. (1987) Systematics of chlorite alteration at the Phelps Dodge massive sulfide deposit. Matagami, Quebec. Economic geology, v. 82, p. 1898-1911 https://doi.org/10.2113/gsecongeo.82.7.1898
  15. So, C.S., Shelton, K.L., Chi S.J., and Choi, S.H. (1988) Stable isotope and fluid inclusion studies of goldsilver-bearing hydrothermal vein deposits, Cheonan-Cheongyang-Nonsan mining district, Republic of Korea: Cheongyang area. Journal of Korean Institute of Mining Geology, v. 21, p. 149-164
  16. Helgeson, H.C. and Kirkham, D.H. (1974) Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures. II. Debye-Huckel parameters for activity coefficients and relative partial molal properties. American Journal of Science, v. 274, p. 1199-1261 https://doi.org/10.2475/ajs.274.10.1199
  17. Kang, P.S. and Im, P.S. (1974) Geological map of Kwangjung sheet. Geological Survey of Korea
  18. Lee, J.H. (1992) Hydrothermal copper mineralization in the Goseong district, Korea. Ph.D. thesis, Korea University, 177p
  19. Yun, S.P., Moon, H.S. and Song, Y.G. (1994) Mineralogy and genesis of the Pyoungan and Daeheung talc deposits in ultramafic rocks, the Yoogoo area, Republic of Korea. Economic and Environmental Geology, v. 27, p.131-145
  20. Lee, H.K. and Lee, C.H. (1997) Mineralogy and geochemistry of green-colored Cr-bearing sericite from hydrothermal alteration zone of the Narim gold deposit, Korea. Economic and Environmental Geology, v. 30, p. 279-288 https://doi.org/10.1016/S0168-6178(97)80043-2
  21. Hey, M.H. (1954) A new review of the chlorites. Mineralogical Magazine, v. 3, p. 87-102
  22. Lee, C.H., Lee, H.K., Yoo, B.C. and Cho, A. (1998b) Geochemical enrichment and migration of environmental toxic elements in stream sediments and soils from the Samkwang Au-Ag mine area, Korea. Economic and Environmental Geology, v. 31, p. 111-125
  23. Chang, S.W. (1988) Mineralogy of tungsten ores from Sangdong mine. Ph.D. thesis, Seoul National University, 287p
  24. Grant, J.A. (1986) The isocon diagram-A simple solution to Gresens' equation for metasomatic alteration. Economic Geology, v. 81, p. 1976-1982 https://doi.org/10.2113/gsecongeo.81.8.1976
  25. Neall, F.B. and Phillips, G.N. (1987) Fluid-wallrock interaction in an Archean hydrothermal gold deposit: A thermodynamic model for the Hunt mine, Kambalda. Economic Geology, v. 82, p. 1679-1694 https://doi.org/10.2113/gsecongeo.82.7.1679
  26. Garrels, R.M. and Christ, C.L. (1965) Solutions, minerals and equilibria. Freeman, Cooper and Company, 450p
  27. Arnorsson, S., Sigurdsson, S. and Svarvarsson, H. (1982) The chemistry of geothermal waters in Iceland. I. Calculation of aqueous speciation from $0^{\circ}$ to $370^{\circ}C$. Geochimica et Cosmochimica Acta, v. 46, p. 1513-1532 https://doi.org/10.1016/0016-7037(82)90311-8
  28. Gresens, R.L. (1967) Composition-volume relationships of metasomatism. Chemical Geology, v. 2, p. 47-65 https://doi.org/10.1016/0009-2541(67)90004-6
  29. Yoo, B.C., Lee, H.K. and Choi, S.G. (2002) Stable isotope, fluid Inclusion and mineralogical studies of the Samkwang gold-silver deposits, Republic of Korea. Economic and Environmental Geology, v. 35, p. 299-316
  30. Rose, A.W. and Burt, D.M. (1979) Hydrothermal alteration: In geochemistry of hydrothermal ore deposits, 2nd ed., Wiley-Interscience, p. 173-235
  31. Ohta, E. and Yajima, J. (1988) Magnesium to iron ratio of chlorite as indicater of type of hydrothermal ore deposit. Mining Geology Special Issue, p. 17-22
  32. Walshe, J.L. and Solomon, M. (1981) An investigation into the environment of formation of the volcanichosted Mt. Lyell copper deposits, using geology, mineralogy, stable isotopes, and a six-component chlorite solid solution model. Economic Geology, v. 76, p. 246-284 https://doi.org/10.2113/gsecongeo.76.2.246
  33. Helgeson, H.C., Delany, J.M., Nesbitt, H.W. and Bird, D.K. (1978) Summary and critique of the thermodynamic properties of rock forming minerals. American Journal of Science, v. 278-A, 229p
  34. Hofmann, A. (1972) Chromatographic theory of infiltration metasomatism and its application to feldspar. American Journal of Sciences, v. 272, p. 69-90
  35. Lee, J.H. and Hueley, P.M. (1973) U-Pb zircon age of the Precambrian basement gneisses of South Korea. Geology and ore deposit No.21, Geological and mineral institute of Korea, p.5-7.
  36. Lee, H.K., Yoo, B.C., Kim, K.W. and Choi, S.G. (1998a) Mode of occurrence and chemical composition of electrums from the Samkwang gold-silcer deposits, Korea. Journal of the Korean Institute of Mineral and Energy Resource Engineers, v. 35, p. 8-18
  37. Walshe, J.L. (1986) A six-component chlorite solid solution model and the conditions of chlorite formation in hydrothermal and geothermal system. Economic Geology, v. 81, p. 687-703
  38. Yoo, B.C., Chi, S.J., Lee, G.J., Lee, J.K. and Lee, H.K. (2007) Element dispersion and wall-rock alteration from Daebong gold-silver deposit, Republic of Korea. Economic and Environmental Geology, v. 40, p. 713-726
  39. De Caritat, P., Hutcheon, I. and walshe, J.L. (1993) chlorite geothermometry: A review. Clays and Clay Minerals, v. 41, p. 219-239 https://doi.org/10.1346/CCMN.1993.0410210
  40. Woo, Y.K., Choi, S.W. and Park, K.H. (1991) Genesis of talc ore deposits in the Yesan area of Chungnam, Korea. The Journal of the Korean Institute of Mining Geology, v. 24, p. 363-378