Geosciences Journal

The Association of Korean Geoscience Societies (한국지질과학협의회)
권호 표지
DOI QR코드

DOI QR Code

New discoveries, skarn zonation, and skarn textures at the Geodo Mine in the Taebaeksan Basin, South Korea

  • Kim, Eui-Jun (Korea Institute of Geoscience and Mineral Resources) ;
  • Yang, Seok-Jun (Korea Institute of Geoscience and Mineral Resources) ;
  • Shin, Seungwook (Korea Institute of Geoscience and Mineral Resources) ;
  • Nam, Hyeong-Tae (Korea Institute of Geoscience and Mineral Resources) ;
  • Shin, Dongbok (Department of Geoenvironmental Sciences, Kongju National University) ;
  • Im, Heon-Kyoung (Department of Geoenvironmental Sciences, Kongju National University) ;
  • Oh, Il-Hwan (Korea Institute of Geoscience and Mineral Resources) ;
  • No, Sang-Gun (Korea Institute of Geoscience and Mineral Resources) ;
  • Cho, Sung-Jun (Korea Institute of Geoscience and Mineral Resources) ;
  • Park, Maeng-Eon (Department of Environmental Geosciences, Pukyong National University)
  • Received : 2018.03.21
  • Accepted : 2018.09.20
  • Published : 2018.12.01
⟨ Previous Next ⟩

Abstract

The Geodo skarn deposit is located in the Taebaeksan Basin, central eastern Korean Peninsula. The geology of the deposit consists of Cambrian to Ordovician calcareous sedimentary rocks and the Cretaceous Eopyeong granitoids. The skarns at Geodo occur around the Eopyeong granitoids, which consist, from early to late, of magnetite-bearing equigranular quartz monzodiorite, granodiorite, and dykes. These dykes emanated randomly from equigranular granodiorite and some of dykes spatially accompany skarns. Skarn Fe mineralization, referred as Prospect I and II in this study, is newly discovered beyond previously known skarns adjacent to the quartz monzodiorite. These discoveries show a vertical and lateral variation of skarn facies, grading from massive reddish-brown garnet-quartz in a lower and proximal zone to banded in an upper and distal zone, reflecting changes in lithofacies of the host rocks. Skarn veins in distal locations are parallel to sedimentary laminae, suggesting that lithologic control is important although proximal skarn has totally obliterated primary structures, due to intense retrograde alteration. Skarns at Geodo are systematically zoned relative to the causative dykes. Skarn zonation comprises proximal garnet, distal pyroxene, and vesuvianite (only in Prospect I) at the contact between skarn and marble. Retrograde alteration is intensely developed adjacent to the contact with dykes and occurs as modification of the pre-existing assemblages and progressive destruction such as brecciation of the prograde assemblages. The retrograde alteration assemblages consist predominantly of epidote, K-feldspar, amphibole, chlorite, and calcite. Most of the magnetite (the main ore mineral), replaces calc-silicate minerals such as garnet in the lower proximal exoskarn, whereas it occurs massive in distal pyroxene and amphibole in the upper and distal exoskarn. The emanation of dykes from the equigranular granodiorite has provided channelways for ascent of skarn-forming fluids from a deep source, whereas the style and nature of skarns suggest that originally structurally-controlled skarn-forming fluids may migrate long distances laterally to produce skarn in calcareous sedimentary rocks.

Keywords

Acknowledgement

Supported by : Korea Institute of Geoscience and Mineral Resources

References

  1. Chang, H.W. and Park, K.H., 1982, Petrogenesis of Fe-Cu bearing Skarn at Keodo. Report of metal deposit, Korea Institute of Energy Research, 14, p. 129-155.
  2. Choi, E., Choi, S.G., and Cho, S.J., 2014, Geochemical characteristics of productive igneous rocks and skarn formation in the Geodo Fe- Cu(-Au) deposits. Proceedings of the 69th Conference of the Geological Society of Korea, Jeongseon, Korea, Oct. 29-Nov. 1, p. 65.
  3. Choi, D.K., Chough, S.K., Kwon, Y.K., Lee, S.B., Woo, J., Kang, I., Lee, H.S., Lee, S.M., Sohn, J.W., Shin, Y.J., and Lee, D.J., 2004, Taebaek Group (Cambro-Ordovician) in the Seokgaejae section, Taebaeksan Basin: a refined lower Paleozoic stratigraphy in Korea. Geosciences Journal, 8, 125-151. https://doi.org/10.1007/BF02910190
  4. Choi, S.G., Choi, B.K., Ahn, Y.H., and Kim, T.H., 2009, Re-evaluation of genetic environments of zinc-lead deposits to predict hidden skarn orebody. Economic and Environmental Geology, 42, 301-314.
  5. Chough, S.K., Kwon, S.T., Ree, J.H., and Choi, D.K., 2000, Tectonic and sedimentary evolution of the Korean Peninsula: a review and new view. Earth Science Review, 52, 175-235. https://doi.org/10.1016/S0012-8252(00)00029-5
  6. Kim, J.H. and Lee, J.D., 1991, Geologic structures of the Yemi area, Kangweon-do, Korea. Journal of the Geological Society of Korea, 27, 500-514.
  7. Kim, J.H, Lee, J., and Lee, H.B., 1988, Geological structures of Baeksan- Sangcheolam area, Samcheog coalfield, Korea. Journal of the Geological Society of Korea, 24, 417-430.
  8. Kim, J.H. and Won, C.H., 1987, Structural analysis of Hwangji-area, Samcheog coalfield, Korea. Journal of the Geological Society of Korea, 23, 136-144.
  9. Kim, J.H., Lee, J.Y., and Nam, K.H., 1994, Pre-Jurassic thrust movement in Danyang area, Danyang coalfield, Korea. Journal of the Geological Society of Korea, 30, 35-40. (in Korean with English abstract)
  10. Kim, E.J., Park, M.E., and White, N.C., 2012, Skarn gold mineralization at the Geodo Mine, South Korea. Economic Geology, 107, 537-551. https://doi.org/10.2113/econgeo.107.3.537
  11. Kim, E.J., Shin, D., Shin, S., Nam, H.T., and Park, S., 2015, Skarn zonation and rock physical properties of the Wondong Fe-Pb-Zn polymetallic deposit, Korea. Geosciences Journal, 19, 587-598. https://doi.org/10.1007/s12303-015-0017-2
  12. Kim, J.H., 1994, Structure in the Taebaeksan zone. In: Ree, J.H., Cho, M., Kwon, S.T., and Kim, J.H. (eds.), Structure and Metamorphism of the Okcheon Belt. Field Trip Guidebook, IGCP Project 321 Organizing Committee, p. 23-57.
  13. Kobayasi, T., 1966, The Cambro-Ordovician formations and faunas of South Korea. Part X, stratigraphy of the Chosen Group in Korea and south Manchuria and its relation to the Cambro-Ordovician formations of other areas. Section A, the Choseon Group of South Korea. Journal of the Faculty of Science, Univerity of Tokyo, Section II, 16, 1-84.
  14. Kwon, Y.K., Chough, S.K., Choi, D.K., and Lee, D.J., 2006, Sequence stratigraphy of the Taebaek Group (Cambro-Ordovician), mideast Korea. Sedimentary Geology, 192, 19-15. https://doi.org/10.1016/j.sedgeo.2006.03.024
  15. Lee, J.Y., 1987, A geochemical study on trace elements in the granitic rocks in relation to mineralization in the limestone area of the Taebaegsan Basin. Journal of Korean Institute and Mining Geology, 20, 179-196.
  16. Lee, J.Y., Lee, I.H., and Hwang, D.H., 1996, Chemical composition of the Cretaceous granitoids and related ore deposits in the Taebaegsan Basin, Korea. Economic and Environmental Geology, 29, 247-256.
  17. Meinert, L.D., 1995, Compositional variation of igneous rocks associated with skarn deposits - chemical evidence for a genetic connection between petrogenesis and mineralization. In: Thompson, J.F.H. (ed.), Magmas, Fluids, and Ore Deposits. Mineralogical Association of Canada, Short Course Series, 23, p. 401-418.
  18. Sung, K.Y., Park, M.E., Yun, S.T., Moon, Y.H., Yoo, I.K., Kim, R.H., Shin, J.K., and Kim, E.J., 2007, Geochemical exploration for a potential estimation on the carlin-type gold mineralization in northern Mt. Taebaek Mining District, Korea. Economic and Environmental Geology, 40, 537-549.
  19. Woo, K.S. and Park, B.K., 1989, Depositional environments and diagenesis of the sedimentary rocks, Choseon Supergroup, Korea: past, present, and future; the state of the art. Journal of the Geological Society of Korea, 25, 347-363.
  20. Woo, K.S., 1999, Cyclic tidal successions of the Middle Ordovician Maggol Formation in the Taebaeg area, Kangwondo, Korea. Geosciences Journal, 3, 123-140. https://doi.org/10.1007/BF02910269
  21. Yun, H.S., 1986, Petrochemical study on the Cretaceous granitic rocks in the southern area of Hambaeg Basin. Journal of the Korean Institute of Mining Geology, 19, 175-191.

Cited by

  1. Development and Field Test of a Distributed Acquisition System for High Efficiency Deep DC Resistivity Surveys vol.56, pp.2, 2018, https://doi.org/10.32390/ksmer.2019.56.2.129
  2. Petrogenesis of coeval shoshonitic and high-K calc-alkaline igneous suites in the Eopyeong granitoids, Taebaeksan Basin, South Korea: Lithospheric thinning-related Early Cretaceous magmatism in the Ko vol.392, pp.None, 2021, https://doi.org/10.1016/j.lithos.2021.106127
  3. The great Yanshanian metallogenic event of eastern Asia: Consequences from one hundred million years of plate margin geodynamics vol.100, pp.None, 2018, https://doi.org/10.1016/j.gr.2021.02.020