The Journal of the Petrological Society of Korea (암석학회지)

The Petrological Society of Korea (한국암석학회)
권호 표지
DOI QR코드

DOI QR Code

Geology and Constituent Rocks, and Radioactive Values of the Eoraesan Area, Chungju, Korea

충주 어래산지역의 지질 및 구성암류와 방사능 값

  • Kang, Ji-Hoon (Department of Earth and Environmental Sciences, Andong National University) ;
  • Lee, Deok-Seon (Disaster Management Division, Ulsan Metropolitan City) ;
  • Koh, Sang-Mo (Convergence Research Center for Development of Mineral Resources, Korea Institute of Geoscience and Mineral Resources)
  • 강지훈 (안동대학교 지구환경과학과) ;
  • 이덕선 (울산광역시 재난관리과) ;
  • 고상모 (한국지질자원연구원 DMR융합연구단)
  • Received : 2018.06.18
  • Accepted : 2018.06.29
  • Published : 2018.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

The Neoproterozoic Gyemyeongsan Formation and the Mesozoic igneous rocks are distributed in the Eoraesan area, Chungju which is located in the northwestern part of Ogcheon metamorphic zone, Korea, and the rare earth element (REE) mineralized zone has been reported in the Gyemyeongsan Formation. We drew up the detailed geological map by the lithofacies classification, and measured the radioactivity values of the constituent rocks to understand the distribution and characteristics of the source rocks of REE ore body in this paper. It indicates that the Neoproterozoic Gyemyeongsan Formation is mainly composed of metapelitic rock, granitic gneiss, iron-bearing quartzite, metaplutonic acidic rock (banded type, fine-grained type, basic-bearing type, coarse-grained type), metavolcanic acidic rock, and the Mesozoic igneous rocks, which intruded it, are divided into pegmatite, biotite granite, gabbro, diorite, basic dyke. The constituent rocks of Gyemyeongsan Formation show a zonal distribution of mainly ENE trend, and the distribution of basic-bearing type of metaplutonic acidic rock (MPAR-B) is very similar to that of the previous researcher's REE ore body. The Mesozoic biotite granite is regionally distributed unlike the result of previous research. The radioactive value of MPAR-B, which has a range of 852~1217 cps (average 1039 cps), shows a maximum value among the constituent rocks. The maximum-density distribution of radioactive value also agrees with the distribution of MPAR-B. It suggests that the MPAR-B could be a source rock of the REE ore body.

옥천변성대의 북서부에 위치하는 충주 어래산지역은 신원생대 계명산층과 중생대 화성암류가 분포하고, 계명산층 내에 희토류 광화대가 보고된 바가 있다. 이 논문에서는 희토류 광체의 기원암과 그 분포 및 특성을 파악하기 위해 암상구분에 의한 상세한 지질도를 작성하고, 구성암류의 방사능 값을 측정하였다. 그 결과 신원생대 계명산층의 주요 암상은 변성이질암, 화강암질편마암, 함철규암, 변성심성산성암(호상형, 세립형, 함염기성형, 조립형), 변성화산산성암 등으로 구성되어 있고, 이를 관입하는 중생대 화성암류는 페그마타이트, 흑운모화강암, 반려암, 섬록암, 염기성 암맥 등으로 구분된다. 계명산층의 구성암류는 주로 동북동 방향의 대상분포를 보이고, 함염기성형 변성심성산성암의 분포는 이전 연구자에 의해 작성된 희토류 광체의 분포와 매우 유사하다. 그리고 중생대 흑운모화강암은 기존 연구결과와 달리 어래산지역의 전역에 광범위하게 분포한다. 또한 함염기성형 변성심성산성암은 연구지역의 구성암류 중에 가장 높은 방사능 값의 범위(852~1217 cps)와 평균값(1039 cps)을 보인다. 노두별 방사능 값의 최대 밀도를 보이는 분포영역은 또한 함염기성형 변성심성산성암의 분포 영역과 일치한다. 이는 함염기성형 변성심성산성암이 희토류 광체의 기원암일 가능성을 지시한다.

Keywords

References

  1. Cheong, C.-S., Kim, N., Yi, K., Jo, H.J., Jeong, Y.-J., Kim, Y., Koh, S.-M. and Iizuka, T., 2015, Recurrent rare earth element mineralization in the northwestern Okcheon Metamorphic Belt, Korea: SHRIMP U-Th-Pb geochronology, Nd isotope geochemistry, and tectonic implications. Ore Geology Reviews, 71, 99-115. https://doi.org/10.1016/j.oregeorev.2015.05.012
  2. Cluzel, D., Cadet, J.P. and Lapierre, H., 1990, Geodynamics of the Ogcheon belt(South Korea). Tectonophysics, 183, 41-56. https://doi.org/10.1016/0040-1951(90)90187-D
  3. Kang, J.-H., 1994a, Tectonic evolution of the Ogcheon zone, South Korea. Ph.D. thesis, Hiroshima University, Japan, 119 p.
  4. Kang, J.-H., 1994b, Geological structure and tectonics of the Ogcheon zone in the Chungju-Jangseonri area, South Korea. Journal of Science of the Hiroshima University Series C, 10, 11-23.
  5. Kang, J.-H., Hayasaka, Y., Katube, A., Lee, D.-S., Koh, S.-M., Ryoo, C.-R. and Noh, S.Y., 2012a, SHRIMP zircon age of Gyemyeongsan Formation in the Eoraesan area, Chungju, Korea. Proceedings of the Annual Joint Conference, the Petrological Society of Korea and the Mineralogical Society of Korea (Abstracts), Seoul, May 17-19, 73-75.
  6. Kang, J.-H., Hayasaka, Y. and Ryoo, C.-R., 2012b, Tectonic evolution of Central Ogcheon Belt, Korea. Journal of the Petrological Society of Korea, 21, 129-150. https://doi.org/10.7854/JPSK.2012.21.2.129
  7. Kang, J.-H. and Ryoo, C.-R., 1997, Igneous activity and geological structure of the Ogcheon Metamorphic Zone in the Kyemyeongsan area, Chungju, Korea. Journal of the Petrological Society of Korea, 6, 151-165.
  8. Kang, J.-H., Lee, D.-S., Noh, S.-Y., Jeong, J.-W., and Koh, S.-M., 2017, Geology and constituent rocks of the Chungju-Goesan area in the northwestern part of Ogcheon metamorphic zone, Korea: Considering on the history of igneous activities accompanying formation and evolution processes of the Ogcheon rift basin. Journal of the Geological Society of Korea, 53, 51-77. https://doi.org/10.14770/jgsk.2017.53.1.51
  9. Kim, J.-S., Park, M.-E. and Kim, G.-S., 1998, A geochemical study of the alkali granite in the Kyeomyeongsan Formation. Economic and Environmental Geology, 31, 349-360.
  10. Kim, K.W. and Lee, H.K., 1965, Geological report of the Chungju sheet (1:50,000), Korea. Institute of Energy and Resources, 35p.
  11. Na, K.C., Kim, H.S., Lee, D.J. and Lee. S.H., 1982, Comparative studies between Chungju and Seosan Groups. Journal of Korean Institute of Mining Geology, 15, 177-188.
  12. Oh, M.S., 1989, Allanite mineralization in the Mt. Eorae Area. Journal of Korean Institute of Mining Geology, 22, 151-166.
  13. Oh, M.S., Seo, J.R., Koo, S.B. and Choi, C.H., 1988, Rare-Earth mineralization in Kyemyungsan Formation of Ogcheon Group, Mt. Eorae area near Chungju city, Middle Korea. Korea Institute of Energy and Resources Research Report, KR-88-8A, 3-112.
  14. Park, M.-E. and Kim, G.-S., 1995, Genesis of the REE ore deposits, Chungju district, Korea: Occurrence features and geochemical characteristics. Journal of Economic and Environmental Geology of Korea, 28, 599-612.
  15. Park, M.-E. and Kim, G.-S., 1998, Geochemistry of Uranium and Thorium deposits from the Kyemyeongsan pegmatite. Journal of Economic and Environmental Geology of Korea, 31, 365-374.
  16. Reedman, A.J., Fletcher, C.J.N., Evans, R.B., Workman, R.B., Yoon, K.S., Rhyu, H.S., Jeong, S.W. and Park, J.N., 1973, Geological, geophysical and geochemical investigations in the Hwanggangni area Chungchong Pukdo. Geological and Mineral Institute of Korea. Report of Geological and Mineralogical Exploration, Part II, 1, 1-118.
  17. You, B.-W., Lee, G.J. and Koh, S.M., 2012, Mineralogy and mineral-chemistry of REE minerals occurring at mountain Eorae, Chungju. Journal of Economic and Environmental Geology of Korea, 45, 643-659. https://doi.org/10.9719/EEG.2012.45.6.643