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2026 Vol.36, Issue 3 Preview Page

Research Article

Petrographic Characteristics of Fracture-Filling Minerals in Granitic Gneiss from the Andong Area

안동지역 화강편마암에 발달한 단열충전 광물의 기재학적 특성

Dae-Seong Cheon1
,
Junghae Choi2
,
Byung-Gon Chae1
,
Jongkyu Park3*
천 대성1
,
최 정해2
,
채 병곤1
,
박 종규3*
1Principal Researcher, Deep Geological Disposal & Energy Storage Research Center, Geological Safety Division, Korea Institute of Geoscience and Mineral Resources
2Professor, Department of Earth Science Education, Kyungpook National University
3Senior Researcher, Converged Geo-Resources Research Department, Pohang Research Branch, Korea Institute of Geoscience and Mineral Resources
1한국지질자원연구원 국토안전연구본부 방폐물심층처분연구센터 책임연구원
2경북대학교 지구과학교육과 교수
3한국지질자원연구원 포항지질자원실증연구센터 지질자원융합실증연구실 선임연구원
*Corresponding Author
30 September 2026. pp. 393-405
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Abstract

A petrographic study was conducted on fracture-filling minerals in drillcore samples (depth: 31.3–478.8 m) from the campus of Gyeongkuk National University, targeting the Precambrian granitic gneiss. The mineral assemblages and paragenetic sequences of fracture-filling phases were characterized using transmitted polarized-light microscopy, back-scatted electron imaging, and X-ray diffraction analysis. The predominant fracture-filling mineral is calcite, locally accompanied by quartz, pyrite, hematite, chlorite, and epidote. A calcite vein at 176.3 m depth is the thickest observed, reaching 1.1 cm in width. EDS line scanning of the vein revealed compositional zoning, with increasing Mg content toward the vein center. Rietveld semi-quantitative analysis of XRD patterns indicates that a fault zone at 176.3 m depth is composed of carbonate minerals (calcite + siderite, 81%), quartz (13%), and apatite (6%), whereas an interval at 466.7 m depth exhibits a low-temperature hydrothermal alteration assemblage of hematite (58%), smectite (10%), and chlorite (7%). Crosscutting relationships among minerals suggest a paragenetic sequence of calcite (early stage) → quartz (middle stage, local) → pyrite (late stage, reducing conditions) → hematite (latest stage, oxidizing conditions). Clinopyroxene within crystalline limestone at 94.0 m depth is interpreted to be a product of skarn metasomatism of carbonate rocks associated with the intrusion of the Jurassic Andong Granite. The results indicate that the Andong area has experienced multiple tectono-hydrothermal events, and the findings enhance our understanding of groundwater migration pathways through fractures and the evolution of minerals precipitated within fracture networks.

Keywords
fracture-filling minerals
granitic gneiss
hydrothermal activity
paragenetic sequence
Andong

국립경국대학교 부지 내 코어시료(심도 31.3–478.8 m)를 대상으로 선캄브리아기 화강편마암의 단열충전 광물에 대한 암석기재학적 연구를 수행하였다. 편광현미경, 후방산란전자 이미지, 그리고 X-선 회절분석을 통해 단열충전 광물의 종류 및 공생순서를 보고한다. 주요 충전 광물은 방해석이며, 석영, 황철석, 적철석, 녹니석 및 녹염석이 국지적으로 수반된다. 176.3 m 구간의 방해석맥은 두께 1.1 cm로 가장 두껍게 발달하며, EDS 선분석을 통해 맥 중앙부로 갈수록 Mg 함량이 증가하는 조성 누대가 확인되었다. X-선 회절패턴에 대한 리트벨트(Rietveld) 반정량 분석 결과, 176.3 m 구간의 단층대는 탄산염광물(방해석 + 능철석, 81%), 석영(13%) 및 인회석(6%)으로 구성되는 한편, 466.7 m 구간은 적철석(58%), 스멕타이트(10%) 및 녹니석(7%)을 포함하는 저온 열수 변질 조합을 보인다. 절단 관계 분석 결과는 방해석(초기) → 석영(중기, 국지적) → 황철석(후기, 환원성) → 적철석(최후기, 산화성)의 공생 순서를 시사한다. 한편, 94.0 m 구간의 결정질 석회암 내 단사휘석은 쥐라기 안동화강암 관입에 의한 탄산염 암석의 스카른(skarn) 작용의 결과로 해석된다. 본 연구 결과는 안동 지역이 다단계의 지구조-열수 사건을 겪었음을 지시하며, 단열을 통한 지하수의 이동과 단열 내 침전광물의 진화과정을 파악하는데 도움을 줄 수 있을 것으로 기대된다.

키워드
단열충전 광물
화강편마암
열수 활동
공생순서
안동
References
1

Bons, P.D., Elburg, M.A., Gomez-Rivas, E., 2012, A review of the formation of tectonic veins and their microstructures, Journal of Structural Geology, 43, 33-62.

10.1016/j.jsg.2012.07.005
2

Bossart, P., Bernier, F., Birkholzer, J., Bruggeman, C., Connolly, P., Dewonck, S., Fukaya, M., Herfort, M., Jensen, M., Matray, J., Mayor, J.C., Moeri, A., Oyama, T., Schuster, K., Shigeta, N., Vietor, T., Wieczorek, K., 2017, Mont Terri rock laboratory, 20 years of research: Introduction, site characteristics and overview of experiments, Swiss Journal of Geosciences, 110(1), 3-22.

10.1007/s00015-016-0236-1
3

Choi, P.Y., Lee, S.R., Choi, H.I., Hwang, J.H., Kwon, S.K., Ko, I.S., An, G.O., 2002, Movement history of the Andong fault system: Geometric and tectonic approaches, Geosciences Journal, 6(2), 91-102.

10.1007/BF03028280
4

Doebelin, N., Kleeberg, R., 2015, Profex: A graphical user interface for the Rietveld refinement program BGMN, Journal of Applied Crystallography, 48(5), 1573-1580.

10.1107/S160057671501468526500466PMC4603273
5

Hwang, S.K., Jang, Y.D., Lee, Y.J., 2002, Petrogenesis of plutonic rocks in the Andong batholith, The Journal of the Petrological Society of Korea, 11(3-4), 200-213 (in Korean with English abstract).

6

Hwang, S.K., Lee, B.H., 2002, Reversely zoned compositional variations and their origins of the Andong Pluton, Andong Batholith, Korea, Economic and Environmental Geology, 35(1), 75-95 (in Korean with English abstract).

7

Inoue, A., 1995, Formation of clay minerals in hydrothermal environments, In: Velde, B. (Ed.), Origin and Mineralogy of Clays, Springer, 268-329.

10.1007/978-3-662-12648-6_7
8

Ishibashi, M., Yoshida, H., Sasao, E., Yuguchi, T., 2016, Long term behavior of hydrogeological structures associated with faulting: An example from the deep crystalline rock in the Mizunami URL, Central Japan, Engineering Geology, 208, 114-127.

10.1016/j.enggeo.2016.04.026
9

Kim, G.Y., Koh, Y.K., Bae, D.S., Kim, C.S., 2004, Mineralogical characteristics of fracture-filling minerals from the deep borehole in the Yuseong area for the radioactive waste disposal project, Journal of the Mineralogical Society of Korea, 17(1), 99-114 (in Korean with English abstract).

10

Kim, N.J., Kang, P.J., Lee, H.K., 1970, Geological map of Jungpyeong-dong sheet (1:50,000), Geological Survey of Korea, 1-19 (in Korean with English abstract).

11

Kim, S.W., Kwon, S., Yi, K., Santosh, M., 2014, Arc magmatism in the Yeongnam massif, Korean Peninsula: Imprints of Columbia and Rodinia supercontinents, Gondwana Research, 26(3-4), 1009-1027.

10.1016/j.gr.2013.08.020
12

Lee, S.Y., Baik, M.H., Cho, W.J., 2006, Mineralogical characteristics of calcite observed in the KAERI underground research tunnel, Journal of the Mineralogical Society of Korea, 19(4), 239-246 (in Korean with English abstract).

13

Meinert, L.D., Dipple, G.M., Nicolescu, S., 2005, World skarn deposits, In: Hedenquist, J.W., Thompson, J.F.H., Goldfarb, R.J., Richards, J.P. (Eds.), Economic Geology: One Hundredth Anniversary Volume, 1905-2005, Society of Economic Geologists, Inc., Littleton, CO, 299-336.

10.5382/AV100.11
14

Muchez, Ph., Slobodnik, M., Viaene, W.A., Keppens, E., 1995, Geochemical constraints on the origin and migration of palaeofluids at the northern margin of the Variscan foreland, southern Belgium, Sedimentary Geology, 96(3-4), 191-206.

10.1016/0037-0738(94)00118-E
15

Passchier, C.W., Trouw, R.A.J., 2005, Microtectonics, 2nd edition, Springer, 366p.

16

Ramsay, J.G., 1980, The crack-seal mechanism of rock deformation, Nature, 284, 135-139.

10.1038/284135a0
17

Rusk, B.G., Reed, M.H., Dilles, J.H., 2008, Fluid inclusion evidence for magmatic-hydrothermal fluid evolution in the porphyry copper-molybdenum deposit at Butte, Montana, Economic Geology, 103(2), 307-334.

10.2113/gsecongeo.103.2.307
18

Sibson, R.H., 1992, Implications of fault-valve behaviour for rupture nucleation and recurrence, Tectonophysics, 211(1-4), 283-293.

10.1016/0040-1951(92)90065-E
19

Whitney, D.L., Evans, B.W., 2010, Abbreviations for names of rock-forming minerals, American Mineralogist, 95(1), 185-187.

10.2138/am.2010.3371
20

Yoon, R., Song, Y.S., Yi, K., 2014, SHRIMP U-Pb zircon ages of the Yeongju and Andong granites, Korea and their implications, The Journal of the Petrological Society of Korea, 23(3), 209-220 (in Korean with English abstract).

10.7854/JPSK.2014.23.3.209
21

Yoshida, H., Maejima, T., Nakajima, S., Nakamura, Y., Yoshida, S., 2013, Features of fractures forming flow paths in granitic rock at an LPG storage site in the orogenic field of Japan, Engineering Geology, 152, 77-86.

10.1016/j.enggeo.2012.10.007
22

Yuguchi, T., Shoubuzawa, K., Ogita, Y., Yagi, K., Ishibashi, M., Sasao, E., Nishiyama, T., 2019, Role of micropores, mass transfer, and reaction rate in the hydrothermal alteration process of plagioclase in a granitic pluton, American Mineralogist, 104(4), 536-556.

10.2138/am-2019-6786
Information
  • Publisher :Korean Society of Engineering Geology
  • Publisher(Ko) :대한지질공학회
  • Journal Title :The Journal of Engineering Geology
  • Journal Title(Ko) :지질공학
  • Volume : 36
  • No :3
  • Pages :393-405
  • Received Date : 2026-06-22
  • Revised Date : 2026-07-13
  • Accepted Date : 2026-07-13
  • DOI :https://doi.org/10.9720/kseg.2026.3.393
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