Browse > Article
http://dx.doi.org/10.9719/EEG.2011.44.5.413

Geological Structure of the Moisan Epithermal Au-Ag Mineralized Zone, Haenam and its Tectonic Environment at the Time of the Mineralization  

Kang, Ji-Hoon (Department of Earth and Environmental Sciences, Andong National University)
Lee, Deok-Seon (Department of Earth and Environmental Sciences, Andong National University)
Ryoo, Chung-Ryul (Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM))
Koh, Sang-Mo (Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM))
Chi, Se-Jung (Mineral Resources Research Division, Korea Institute of Geosciences and Mineral Resources (KIGAM))
Publication Information
Economic and Environmental Geology / v.44, no.5, 2011 , pp. 413-431 More about this Journal
Abstract
An Epithemal Au-Ag mineralized zone is developed in the Moisan area of Hwangsan-myeon, Haenam-gun, Jeol-lanam-do, Korea, which is located in the southwestern part of the Ogcheon metamorphic zone. It is hosted in the Hwangsan volcaniclastics of the Haenam Formation of the Late Cretaceous Yucheon Group. This research investigated the characteristics of bedding arrangement, fold, fault, fracture system, quartz vein and the time-relationship of the fracture system to understand the geological structure related to the formation of the mineralized zone. On the basis of this result, the tectonic environment at the time of the mineralization was considered. Beds mainly trend east-northeast and gently dip into north-northwest or south-southeast. Their poles have been rearranged by subhorizontal-upright open fold of (east)-northeast trend as well as dip-slip fault. Fracture system was formed through at least 6~7 different deformation events. D1 event; formation phase of the main fracture set of EW (D1-1) and NS (D1-2) trends with a good extensity, D2 event; that of the extension fracture of NW trend, and conjugate shear fracturing of the EW (dextral) and NS (sinistral) trends, D3 event; that of the extension fracture of NE trend, and conjugate shear refracturing of the EW (sinistral) and NS (dextral) trends, D4 event; that of the extension fracture of NS trend showing a poor extensity, D5 event; that of the extension fracture of NW trend, and conjugate shear refracturing of the EW (dextral) and NS (sinistral) trends, D6 event; that of the extension fracture of EW trend showing a poor extensity. Frequency distribution of fracture sets of each deformation event is D1-1 (19.73 %)> D1-2 (16.44 %)> D3=D5 (14.79 %)> D2 (13.70 %)> D4 (12.33 %)> D6 (8.22 %) in descending order. The average number of fracture sets within 1 meter at each deformation event is D6 (5.00)> D5 = D4 (4.67)> D2 (4.60)> D3 (4.13)> D1-1 (3.33)> D1-2 (2.83) in descending order. The average density of all fractures shows 4.20 fractures/1 m, that is, the average spacing of all fractures is more than 23.8 cm. The frequency distribution of quartz veins at each orientation is as follows: EW (52 %)> NW (28 %)> NS (12 %)> NE (8 %) trends in descending order. The average density of all quartz veins shows 4.14 veins/1 m, that is, the average spacing of all quartz veins is more than 24.2 cm. Microstructural data on the quartz veins indicate that the epithermal Au-Ag mineralization (ca. 77.9~73.1 Ma) in the Moisan area seems to occur mainly along the existing D1 fracture sets of EW and NS trends with a good extensity not under tectonic stress but non-deformational environment directly after epithermal rupture fracturing. The D1 fracturing is considered to occur under the unstable tectonic environment which alternates compression and tension of NS trend due to the oblique northward subduction of the Izanagi plate resulting in the igneous activity and deformation of the Yucheon Group and the Bulguksa igneous rocks during Late Cretaceous time.
Keywords
Moisan area; Hwangsan volcaniclastics; Epithennal Au-Ag mineralized zone; fracture system; quartz vein;
Citations & Related Records
Times Cited By KSCI : 4  (Citation Analysis)
연도 인용수 순위
1 Koh, S.M. and Chang, H.W. (1997) Geological and geochemical characteristics of the Bukok hydrothermal clay deposits in the Haenam area, Korea. Resource Geology, v.47, p.29-40.
2 Koh, S.M., Kim, H.-S., Kim, C.K., Yi, M.-J., Jo, Y.-D., Yoo, J.H., Jeong, S.-B., Ryoo, C.-R., Kim, Y.-D., Heo, C.-H., Kim, Y.U., Park, S.-G., Lee, D.K., Son, J.-S., Kim, T.- K., Hong, Y.-K., Park, S.-W., Yang, D.H., Park, J.-T., Kim, S.K., Sohn, J.-S., Lee, J.H., Chi, S.-J., Seo, J.-R., Ko, I.-S., Lee, H.Y., Kim, I.J., Kim, D.-O. and Lee, T.- S. (2009) Technical development on the life cycle of the Haenam epithermal gold mineralized area and hydrothermal clay resources. MKE, GP2009-003- 2009(1), 182p.
3 Koh, S.M., Takagi, T., Kim, M.Y., Hong, S.S. and Sudo, S. (2000) Geological and geochemical characteristics of the hydrothermal clay alteration in South Korea. Resource Geology, v.50, p.229-242.   DOI   ScienceOn
4 Lee D.-S. and Kang, J.-H. (2009) Movement History of Faults Considered from the Geometric and Kinematic Characteristics of Fracture System in Gilan-cheongsong Area, Gyeongsang Basin, Korea. Jour. Petrol. Soc. Korea, v.18, p.293-305.
5 Lee, D.W. (1999) Strike-slip fault tectonics and basin formation during the Cretaceous in the Korean Peninsula. The Island Arc, v.8, p.218-231.   DOI
6 Maruyama, S., Isozaki, Y., Kimura, G. and Terabayashi, M. (1997) Paleogeographic maps of the Japanese Islands: plate tectonic synthesis from 750 Ma to the present. The Island Arc, v.6, p.121-142.   DOI
7 Park, S.-I., Kim, Y.-S., Ryoo, C.-R. and Sanderson, D.J. (2010) Fractal analysis of the evolution of a fracture network in a granite outcrop, SE Korea. Geosciences Journal, v.14, p.201-215.   DOI   ScienceOn
8 Peacock, D.C.P. (2001) The temporal relationship between joints and faults. Journal of Structural Geology, v.23, p.329-341.   DOI   ScienceOn
9 Petit, J.-P. (1988) Can natural fractures propagate under mode II condition?. Tectonics, v.7, p.1243-1256.   DOI
10 Pollard, D.D. and Aydin, A. (1988) Progress in understanding jointing over the past century. Geological Society of America Bulletin, v.100, p.1181-1204.1: 50,000.   DOI
11 Rawnsley, K.D., Peacock, D.C.P., Rives, T. and Petit, J.P. (1998) Jointing in the Mesozoic sediments around the Bristol Channel Basin. Journal of Structural Geology, v.20, p.1641-1661.   DOI   ScienceOn
12 Choi, S.-G., Ryu, I.-C., Pak, S.J., Wee, S.-M., Kim, C.S. and Park, M.-E. (2005) Cretaceous epithermal goldsilver mineralization and geodynamic environment, Korea. Ore Geology Reviews, v.26, p.115-135.   DOI   ScienceOn
13 Chough, S.K. and Sohn, Y.K. (2010) Tectonic and sedimentary evolution of a Cretaceous continental arcbackarc system in the Korean penisula: New view. Earth Science Reviews, v.101, p.225-249.   DOI   ScienceOn
14 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 Reviews, v.52, p.175-235.   DOI   ScienceOn
15 Chun, S.S. and Chough, S.K. (1995) The Cretaceous Uhangri Formation, SW Korea: lacustrine margin facies. Sedimentology, v.42, p.293-322.   DOI   ScienceOn
16 Eyal, Y., Gross, M.R., Engelder, T. and Becker, A. (2001) Joint development during fluctuation of the regional stress field in southern Israel. Journal of Structural Geology, v.23, p.279-296.   DOI   ScienceOn
17 Hancock, P.L., Al Kadhi, A. and Sha'at, N.A. (1984) Regional joint sets in the Arabian Platform as indicators of intraplate processes. Tectonics, v.3, p.27-43.   DOI
18 Kim, C.S. and Choi, S.G. (2009) Potassium-Argon ages of the epithermal gold-silver mineralizaton in the Haenam- Jindo area, southwestern Korea. Resource Geology, v.59, p.415-421.   DOI   ScienceOn
19 Jeong, J.O. and Jwa, Y.J., (2000) Volcanic stratigraphy and petrology of Cretaceous volcanic rocks in the eastern part of the Euiseong Basin. Jour. Petrol. Soc. Korea v.9, p.238-253.
20 Kang, J.-H. and Ryoo, C.-R. (2006) Geometrical Interpretation on the development Sequence and the Movement Sense of Fractures in the Cheongsong Granite, Gilan-myeon Area, Uiseong Block of Gyeongsang Basin, Korea. Jour. Petrol. Soc. Korea, v.15, p.180-193.
21 Kim, E.-J., Hong, Y.-K. and Chi, S.-J. (2011) Geochemical Variation of Hwangsan Volcanic Complex by Large Hydrothermal Alteration. Econ. Environ. Geol., v.44, p.95-107.   DOI
22 Kim, I.J. and Nagao, K. (1992) K-Ar ages of the hydrothermal clay deposits and the surrounding igneous rocks in southwest Korea. Jour. Petrol. Soc. Korea, v.1, p.58-70.
23 Koh, S.M. (1996) Geochemical characteristics of the Cretaceous volcanic rocks and Bukok hydrothermal deposits in the Haenam volcanic field, Chollanamdo, Korea. Unpublished Ph.D. thesis, Seoul National University, Korea, 181p.
24 Choi, P.-Y., Kwon, S.-K., Lee, S.R., Hwang, J.-H., Angelier, J. and An, G.-O. (2002b) Late Mesozoic-Cenozoic tectonic sequence of Southeast Korea. In Jin, M.-S., Lee, S.R., Choi, H.-I., Park, K.-H., Koh, S.-M. and Cho, D.-L.(ed.) Mesozoic sedimentation, igneous activity and mineralization in South Korea. KIGAM, p.52-88.
25 Bowden, C.D. (2007) Epithermal systems of the Seongsan district, South Korea; an investigation on the geological setting and spatial and temporal relationships between high and low sulfidation systems. Ph.D. thesis, James Cook University, Australia, 334p.
26 Choi, P.-Y. and Choi, Y.S. (2007) Stress Model of the Opening of the Cretaceous Eumseong Basin. KIGAM Bulletin, v.11, p.3-16.
27 Choi, P.-Y., Choi, H.-Y., Hwang, J.-H., Kee, W.-S., Choi, Y.S., Lee, B.-J. and Kim, Y.B. (2002a) Explanatory note of the Mokpo and Yeosu sheets (1:250,000). KIGAM, 25p.
28 Choi, P.-Y., Lee, S.R., Choi, H.I., Hwang, J.-H., Kwon, S.- K., Ko, I.-S. and An, G.-O. (2002c) Movement history of the Andong Fault System: Geometric and tectonic approaches. Geosciences Journal, v.6, p.91-102.
29 Son, M., Chong, H.-Y. and Kim, I.-S. (2002) Geology and geological structures in the vicinities of the southern part of the Yonil tectonic line, SE Korea. Jour. Geol. Soc. Korea, v.38, p.175-197.
30 Reches, Z. and Lockner, D.A. (1994) Nucleation and growth of faults in brittle rocks. Journal of Geophysical Research, v.99, p.18159-18174.   DOI
31 Son, M., Kim, J.-S., Chong, H.-Y., Lee, Y.H. and Kim, I.- S. (2007) Characteristics of the Cenozoic crustal deformation in SE Korea and their tectonic implications. Korean Jour. of Petrol. Geol., v.13, p.1-16.