The Journal of the Petrological Society of Korea (암석학회지)

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

DOI QR Code

Petrology of the Sanbangsan Lava Dome, Jeju Volcanic Field

제주도 산방산 용암돔(Lava Dome)의 구성암석에 대한 화산암석학적 연구

  • Yun, Sung-Hyo (Department of Earth Science Education, Pusan National University)
  • 윤성효 (부산대학교 지구과학교육과)
  • Received : 2019.12.11
  • Accepted : 2019.12.24
  • Published : 2019.12.31
Download PDF
⟨ Previous Next ⟩

Abstract

Petrological studies were performed on the Sanbangsan lava dome, located in the southwest of Jeju Island Volcanic Field. According to the lava ejection method, it is 'an internal primitive form' that is gradually pushed up and expanded by continuous magma injection from the bottom to the top of the vent and it corresponds to the 'low lava dome'. The rocks are partly plotted in the field of benmoreite, but mostly plotted in the field of trachyte of the Cox et al.(1979) classification diagram, and also mainly plotted in the field of trachyte of Le Maitre et al.(2002) and Zr/TiO2-Nb/Y classification diagram. Therefore, the expression that described the rock of Sanbangsan lava dome as 'trachy-andesite' should be corrected to 'trachyte'. The volcanic rocks that consists in the Sanbangsan lava dome are trachyte containing normative quartz and shows differentiation trend in the range of 59.75-63.46 wt.% SiO2.

제주도 남서부에 위치하는 산방산 용암돔에 대하여 암석학적 연구를 수행하였다. 산방산 용암돔의 형태를 용암분출 방식에 따라 분류하면, 화구내의 하부로부터 상부로 계속적인 마그마 주입에 의하여 서서히 밀면서 상승 팽창한 '내부 기원형'에 해당하며, 용암돔 외곽부에 발달하는 테일러스 에이프런은 대부분 침식 제거되고 그 내부의 용암류의 냉각에 의한 수직절리가 발달하고 있는 '낮은 용암돔형'에 해당한다. 산방산을 구성하는 암석을 화산암 TAS 분류도에 적용하여 분류하면, Cox et al.(1979) 분류도에서 일부 벤모리아이트 영역에 도시되나 대부분이 조면암의 영역에 도시되며, 최근 사용하는 Le Maitre et al.(2002)의 분류도와 Zr/TiO2-Nb/Y 분류도에서는 모두 조면암의 영역에 도시된다. 그러므로 산방산 용암돔을 구성하는 암석을 '조면암질 안산암'이라고 설명한 표현은 마땅히 '조면암'으로 수정되어야 할 것이다. 산방산 용암돔을 구성하는 화산암은 노옴 석영을 함유하는 조면암으로 SiO2 59.75-63.46 wt.%의 범위에서 일정한 분화 경향을 보인다.

Keywords

References

  1. Blake, S., 1989, Viscoplastic models of lava domes, IAVCEI Proceddings in Volcanology, Vol.2. Lava flows and domes, Springer Verlag, Heidelberg, 88-126.
  2. Carmichael, I.S.E., 1965, Trachytes and their feldspar phenocrysts. Mineralogical Magazine and Journal of the Mineralogical Society, 34, 107-125. https://doi.org/10.1180/minmag.1965.034.268.09
  3. Chang, K.H., Park, J.B. and Kwon, S.T., 1999, Petrography and mineral chemistry of trachytes in Cheju volcanic island, Korea. Journal of the geological Society of Korea, 35(1), 15-34. (in Korean with English abstract)
  4. Chang, K.H., Park, J.B. and Kwon, S.T., 2006, Geochemical characteristics of trachytes in Jeju Island. Journal of the Geological Society of Korea. 42(2), 235-252. (in Korean with English abstract)
  5. Cox, K.G., Bell, J.D., and Pankhurst, R.J., 1979, The interpretation of igneous rocks (1st edition): Springer Netherlands, 450p.
  6. Koh, K.W. and Park, J.B., 2010, The study on geology and volcanism in Jeju Island (III): Early lava effusion records in Jeju Island on the basis of $^{40}Ar/^{39}Ar$ absolute ages of lava samples. Economic and Environmental Geology, 43(2), 163-176. (in Korean with English abstract)
  7. Koh, K.W., Park, J.B., Kang, B.R., Kim, G.P. and Moon, D.C., 2013, Volcanism in Jeju Island. Journal of the Geological Society of Korea, 49, 209-230. (in Korean with English abstract)
  8. Lee, D.Y., Yun, S.K., Kim, J.Y. and Kim, Y.J., 1987, Quaternary geology of the Jeju Island. Korea Institute Energy & Resources Report 87-29, 233-278. (in Korean)
  9. Lee, M.W., 1982, Petrology and geochemistry of Jeju volcanic island, Korea. Science Reports of the Tohoku University, Series III, 15, 177-256.
  10. Lee, M.W., Won, C.K., Lee, D.Y., Park, G.H. and Kim, M.S., 1994, Stratigraphy and petrology of volcanic rocks in southern Cheju Island, Korea. Journal of Geolgical Society of Korea, 30(6), 521-541. (in Korean with English abstract)
  11. Le Maitre, R.W., 1989, A Classification of Igneous Rocks and Glossary of Terms. Recommendations of the IUGS Commission on the Systematics of Igneous Rocks. Oxford: Blackwell.
  12. Le Maitre, R.W., 2002. Igneous Rocks: A classification and glossary of terms: recommendations of the International Union of Geological Sciences, Subcommission on the Systematics of Igneous Rocks. Cambridge University Press, Cambridge.
  13. Park, K.H., Cho, D.L. and Kim, J.C., 2000, Geological report of the Moseulpo-Hanlim sheet (1:50,000). Korea Institute of Geology, Mining and Materials, 56p (in Korean with English abstract).
  14. Pearce, J.A., Harris, N.W. and Tindle, A.G., 1984, Trace element discrimination diagrams for the tectonic interpretation of granitic rocks. Journal of Petrology, 25, 956-983. https://doi.org/10.1093/petrology/25.4.956
  15. Winchester, J.A. and Floyd, P.A., 1977, Geochemical discrimination of different magma series and their differentiation products using immobile elements. Chemical Geology 20, 325-343. https://doi.org/10.1016/0009-2541(77)90057-2
  16. Won, C.K., Matsuda, J., Nagao, K., Kim, K.H. and Lee, M.W., 1986, Paleomagnetism and radiometric age of trachytes in Jeju Island, Korea. The Journal of Korea Institute of Mining Geology, 19, 25-33. (in Korean with English abstract)
  17. Wood, D.A., 1980, The application of a Th-Hf-Ta diagram to problems of tectono- magmatic classification and to establishing the nature of crustal contamination of basaltic lavas of the British Tertiary volcanic province. Earth and Planetary Science Letters 50, 11-30. https://doi.org/10.1016/0012-821X(80)90116-8
  18. Yun, S.K., Han, D.S. and Lee, D.Y. (1987) Quaternary geology in the southern part of Jeju Island. Korea Institute of Energy & Resources Report, KR-86-2-(B)-2, 64p. (in Korean)
  19. https://100.daum.net/encyclopedia/view/b11s1225a
  20. https://100.daum.net/encyclopedia/view/14XXE0026233
  21. https://100.daum.net/encyclopedia/view/24XXXXX76823