암석학회지 (The Journal of the Petrological Society of Korea)

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

DOI QR Code

울릉도 말잔등응회암에서 시간에 따른 조성변화에 근거한 마그마 진화

Magmatic Evolutions based on Compositional Variations with Time in the Maljandeung Tuff, Ulleung Island, Korea

  • 황상구 (안동대학교 지구환경과학과) ;
  • 이소진 (안동대학교 기초과학연구소) ;
  • 안웅산 (제주특별자치도 세계유산본부)
  • Hwang, Sang Koo (Department of Earth and Environmental Sciences, Andong National University) ;
  • Lee, So-Jin (Institute of Basic Science, Andong National University) ;
  • Ahn, Ung San (World Heritage Office, Jeju Special Self-govering Provincial Government)
  • 투고 : 2019.05.27
  • 심사 : 2019.06.24
  • 발행 : 2019.06.30
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

울릉도는 동해의 해저에서 3,200 m 판내 알칼리 화산의 상단부로 해수면 위에 984.6 m 높이로 출현한 섬이다. 이는 대체로 현무암질에서 조면암질과 포놀라이트질 마그마의 분출에 의해 형성되었으며, 도동현무암질암류, 울릉층군, 성인봉층군과 나리층군으로 구분된다. 최후기에 형성된 나리층군 중 말잔등응회암은 약 18.8~5.6 ka B.P.에 폭발적으로 분출하였으며, 4개 멤버(N-5, U-4, 3, 2)로 구성되는 두꺼운 화성쇄설성 층서로 이루어져 있다. 화학적 자료에 의하면, 최하부의 N-5는 포놀라이트질이고 불호정성 원소가 상당히 풍부하고 희토류(REE) 패턴이 뚜렷한 부의 Eu 이상을 나타낸다. 상부의 멤버 U-4, 3 및 2는 포놀라이트질 내지 테프리포놀라이트질이고 REE 패턴이 큰 Eu 이상을 가지지 않는다. 변화 경향도에서 많은 원소들은 멤버들간에 조성적 단절을 보여주며, 각 멤버(특히 U-4, 3 및 2) 내에서는 하부에서 상부로 감에 따라 포놀라이트질에서 테프리포놀라이트질로 점진적으로 고철질 조성이 증가하는 체계적인 변화 양상을 보여준다. 이는 마그마챔버 내에서 마그마 조성이 상부의 포놀라이트질에서 하부의 테프리포놀라이트질로 변화하는 고철질 누대를 형성했음을 지시한다. 이 화학적 성층화는 마그마챔버에서 열중력확산, 결정분별작용과 점진적 용융 및 순차적 정치 등에 의해 복합적 기구로부터 일어났다고 생각된다. 이 성층화 마그마는 짧은 기간(약 11 ka) 동안 폭발적으로 분출되었고 작은 칼데라를 형성하였다. 특히 두 멤버(U-3, 2)는 각각 8.4 ka B.P.와 5.6 ka B.P. 시기에 성층화된 마그마챔버에서 상부의 포놀라이트질 조성대로부터 하부의 테프리포놀라이트질 조성대로 점진적으로 분출됨으로서 축적되었다.

Ulleung Island is the top of an intraplate alkalic volcano rising 3200 m from sea floor in the East Sea (or Sea of Japan). The emergent 984.6 m consist of eruptive products of basaltic, trachytic and phonolitic magmas, which are divided into Dodong Basaltic Rocks, and Ulleung, Seonginbong and Nari groups. The Maljandeung Tuff in the Nari Group consists of thick pyroclastic sequences which are subdivided into 4 members (N-5, U-4, 3, 2), generating from explosive eruptions during past 18.8~5.6 ka B.P. From chemical data, the Member N-5, phonolitic in composition, is considerably enriched in incompatible elements and REE patterns with significant negative Eu anomalies. The members 4, 3 and 2 are phonolitic to tephriphonolitic in composition, and their REE patterns do not have significant Eu anomalies. In variation trend diagrams, many elements show abrupt compositional gaps between members, and gradual upward-mafic variations from phonolite to tephriphonolite within each member. It suggests a downward-mafic zonation that were evolved into phonolitic zone in the lower part to tephriphonolitic zone in upper part of magma chamber. It is supposed that the chemical stratification generated from multiple mechanisms of thermal gravidiffusion, crystal fractionation, and gradual melting and sequential emplacement. The stratified magmas were explosively erupted to generate a small caldera during short period (11 ka B.P.). Especially both members (U-3, 2) were accumulated by gradually erupting from the upper phonoltic zone to the lower tephriphonoltic zone of the stratified chamber in 8.4 ka B.P. and 5.6 ka B.P. time, respectively.

키워드

HGOSBQ_2019_v28n2_111_f0001.png 이미지

Fig. 1. Geological map of Ulleung Island (after Hwang et al., 2012).

HGOSBQ_2019_v28n2_111_f0002.png 이미지

Fig. 2. Columnar section for extracaldera pyroclastic sequences of the Maljandeung near Naesujeon hill (A) and Jeodong hill (B).

HGOSBQ_2019_v28n2_111_f0003.png 이미지

Fig. 3. Classification of the volcanic rocks of Nari Group on the total alkali silica (TAS) diagram (from Le Bas et al., 1986).

HGOSBQ_2019_v28n2_111_f0004.png 이미지

Fig. 4. Harker variation diagrams of the major elements versus SiO2 for the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0005.png 이미지

Fig. 5. Harker variation diagrams of some trace elements versus Th for the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0006.png 이미지

Fig. 6. Trace element variations in the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0007.png 이미지

Fig. 7. Chondrite-normalized REE patterns for the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0008.png 이미지

Fig. 8. Normalized spider diagram patterns for selected elements for theMaljandeung Tuff. Values are normalized to primordial or Archean mantle from Sun and Nesbitt(1977). Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0009.png 이미지

Fig. 9. Variation trend diagram for the major elements of the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0010.png 이미지

Fig. 10. Variation trend diagram for the trace and rare earth elements of the Maljandeung Tuff. Symbols are the same as those in Fig. 3.

HGOSBQ_2019_v28n2_111_f0011.png 이미지

Fig. 11. Triangular diagrams for petrotectonic discriminance.

Table 1. Major element compositions (wt.%) for the pumice clasts from the Maljandeung Tuff in Ulleung Island

HGOSBQ_2019_v28n2_111_t0001.png 이미지

Table 2. Trace and rare earth element abundances (ppm) for the pumice clasts from the Maljandeung Tuff in Ulleung Island

HGOSBQ_2019_v28n2_111_t0002.png 이미지

Table 2. Continued

HGOSBQ_2019_v28n2_111_t0003.png 이미지

참고문헌

  1. Andujar, J., Costa, F., Marti, J., Wolff, J.A. and Carroll, M.R., 2008, Experimental constraints on pre-eruptive conditions of phonolitic magma from the caldera-forming El Abrigo eruption, Tenerife (Canary Islands). Chemical Geology, 257, 173-191. https://doi.org/10.1016/j.chemgeo.2008.08.012
  2. Brenna, M., Price, R., Cronin, S.J., Smith, I.E.M., Sohn, Y.K., Kim, G.B. and Maas, R., 2014. Final magma storage depth modulation of explosivity and trachyte-phonolite genesis at an intraplate volcano: a case study from Ulleung Island, South Korea. Journal of Petrology, 55, 709-747. https://doi.org/10.1093/petrology/egu004
  3. Choi, S.H., Mukasa, S.B., Kwon, S.T. and Andronikov, A.V., 2006, Sr, Nd, Pb and Hf isotopic compositions of late Cenozoic alkali basalts in South Korea: evidence for mixing between the two dominant asthenospheric mantle domains beneath East Asia. Chemical Geology, 232, 134-151. https://doi.org/10.1016/j.chemgeo.2006.02.014
  4. Francis, D. and Ludden, J., 1995, The signature of amphibole in mafic alkaline lavas, a study in the northern Canadian Cordillera. Journal of Petrology, 36, 1171-1191. https://doi.org/10.1093/petrology/36.5.1171
  5. Hall, A., 1966, A petrogenetic study of the Rosses granite Complex, Donegal. Journal of Petrology, 7, 202-220. https://doi.org/10.1093/petrology/7.2.202
  6. Hildreth, W., 1979, The Bishop Tuff: Evidence for the origin of compositional zonation in silicic magma chambers. Geological Society of America Special Paper 180, 43-75.
  7. Hobson, A., Bussy, F. and Hernandez, J., 1998, Shallowlevel migmatization of gabbros in a metamorphic contact aureole, Fuerteventura Basal Complex, Canary Islands. Journal of Petrology, 39, 1025-1037. https://doi.org/10.1093/petroj/39.5.1025
  8. Hwang, S.K., Hwang, J.H. and Kwon, C.W., 2012, Geological report of the Ulleung Sheet. Korea Institute of Geoscience and Mineral Resources, 84p.
  9. Hwang, S.K. and Jo I.H., 2014, Petrologic Evolution Processes of the Latest Volcanic Rocks in Ulleung Island, East Sea. Journal of Geological Society of Korea, 50, 343-363 (in Korean with English abstract). https://doi.org/10.14770/jgsk.2014.50.3.343
  10. Hwang, S.K., Kim, J.H. and Jang, Y., 2017, Volcanism and Petrogenesis of Dodong Basaltic Rocks in the Ulleung Island, East Sea. Journal of Petrological Society of Korea, 26, 361-371 (in Korean with English abstract). https://doi.org/10.7854/JPSK.2017.26.4.361
  11. Hwang, S.K., Lee, S.-J. and Han, K.H., 2018, Interpretation of volcanic eruption types from granulometry and component analyses of the Maljandeung Tuff, Korea. Journal of Geological Society of Korea, 54, 513-527. https://doi.org/10.14770/jgsk.2018.54.5.513
  12. Im, J.H., Shim, S.H., Choo, C.O., Jang, Y.D. and Lee, J.S., 2012, Volcanological and paleoenvironmental implications of charcols of the Nari Formation in Nari Caldera, Ulleung Island, Korea. Geosciences Journal, 16, 105-114. https://doi.org/10.1007/s12303-012-0020-9
  13. Irving, A.J. and Green, D.H., 2008, Phase relationships of hydrous alkalic magmas at high pressures: production of nepheline hawaiitic to mugearitic liquids by amphiboledominated fractional crystallization within the lithospheric mantle. Journal of Petrology, 49, 741-756. https://doi.org/10.1093/petrology/egm088
  14. Johansen, T.S., Hauff, F., Hoernle, K., Klugel, A. and Kokfelt, T.F., 2005, Basanite to phonolite differentiation within 1550-1750 yr: U-Th-Ra isotopic evidence from the A.D. 1585 eruption on La Palma, Canary Islands. Geology, 33, 897-900. https://doi.org/10.1130/G21663.1
  15. Johnson, D.M., Hooper, P.R. and Conrey, R.M., 1999, XRF analysis of rocks and minerals for major and trace elements on a single low dilution Li-tetraborate fused bead. Advanced in X-ray Analysis, 41, 843-867.
  16. Kim, G.B., Cronin, S.J., Yoon, W.S. and Sohn, Y.K., 2014, Post 19 ka B.P. eruptive history of Ulleung Island, Korea, inferred from an intra-caldera pyroclastic sequence. Bulletin of Volcanology, 76, 802-828. https://doi.org/10.1007/s00445-014-0802-1
  17. Kim, G.B., Yoon, S.H., Chough, S.K., Kwon, Y.K. and Ryu, B.J., 2011, Seismic reflection study of acoustic basement in the South Korea Plateau, the Ulleung Interplain Gap, and the northern Ulleung Basin: volcanotectonic implications for Tertiary back-arc evolution in the southern East Sea. Tectonophysics, 504, 43-56. https://doi.org/10.1016/j.tecto.2011.02.004
  18. Kim, H.-J., Jou, H.-T., Cho, H.-M., Bijwaard, H., Sato, T., Hong, J.-K. et al., 2003, Crustal structure of the continental margin of Korea in the East Sea (Japan Sea) from deep seismic sounding data: evidence for rifting affected by the hotter than normal mantle. Tectonophysics, 364, 25-42. https://doi.org/10.1016/S0040-1951(03)00048-9
  19. Kim, K.H., Tanaka, T., Nagao, K. and Jang, S.K., 1999, Nd and Sr isotopes and K-Ar ages of the Ulreungdo alkali volcanic rocks in the East Sea, South Korea. Geochemical Journal, 33, 317-341. https://doi.org/10.2343/geochemj.33.317
  20. Legendre, C., Maury, R.C., Caroff, M., Guillou, H., Cotten, J., Chauvel, C. et al., 2005, Origin of exceptionally abundant phonolites on Ua Pou Island (Marquesas, French Polynesia): partial melting of basanites followed by crustal contamination. Journal of Petrology, 46, 1925-1962 https://doi.org/10.1093/petrology/egi043
  21. Lipman, P.W., 1967, Mineral and chemical variations within an ash-flow sheet from Aso caldera, southwestern Japan. Contributions to Mineralogy and Petrology, 16, 300-327. https://doi.org/10.1007/BF00371528
  22. Machida, H. and Arai, F., 1983, Extensive ash falls in and around the Sea of Japan from large late Quaternary eruptions. Journal of Volcanology Geothermal Research, 18, 151-164. https://doi.org/10.1016/0377-0273(83)90007-0
  23. Machida, H., Arai, F., Lee, B. S., Moriwaki, H. and Furuta, T., 1984, Late Quaternary tephras in Ulreungdo Island, Korea, Journal of Geography., 93, 1-14. https://doi.org/10.5026/jgeography.93.1
  24. Mahood, G.A., 1981, Chemical evolution of a Pleistocene rhyolitic center: Sierra La Primavera, Jalisco, Mexico. Contributions to Mineralogy and Petrology, 77, 129-149. https://doi.org/10.1007/BF00636517
  25. Okuno, M., Shiihara, M., Torii, M., Nakamura, T., Kim, K.H., Domitsu, H., Moriwaki., H. and Oda, M., 2010, AMS radiocarbon dating of Holocene tephra layers on Ulleung Island, South Korea. Radiocarbon, 52, 1465-1470. https://doi.org/10.1017/S0033822200046555
  26. Panter, K.S., Kyle, P.R. and Smellie, J.L., 1997, Petrogenesis of a phonolite-trachyte succession at Mount Sidley, Marie Byrd Land, Antarctica. Journal of Petrology, 38, 1225-1253. https://doi.org/10.1093/petroj/38.9.1225
  27. Price, R.C. and Taylor, S.R., 1973, The geochemistry of the Dunedin Volcano, East Otago, New Zealand: rare earth elements. Contributions to Mineralogy and Petrology 40, 195-205. https://doi.org/10.1007/BF00373784
  28. Price, R.C., Johnson, R.W., Gray, C.M. and Frey, F.A., 1985, Geochemistry of phonolites and trachytes from the summit region of Mt. Kenya. Contributions to Mineralogy and Petrology, 89, 394-409. https://doi.org/10.1007/BF00381560
  29. Ridolfi, F. and Renzulli, A., 2012, Calcic amphiboles in calc-alkaline and alkaline magmas: thermobarometric and chemometric empirical equations valid up to 1,1308C and 2.2 GPa. Contributions to Mineralogy and Petrology, 163, 877-895. https://doi.org/10.1007/s00410-011-0704-6
  30. Shiihara, M., Torii, M., Okuno, M., Domitsu, H., Nakamura, T., Kim, K.H., Moriwaki, H. and Oda, M., 2011, Revised stratigraphy of Holocene tephras on Ulleung Island, South Korea, and possible correlatives for the U-Oki tephra. Quaternary International, 246, 222-232. https://doi.org/10.1016/j.quaint.2011.08.030
  31. Smith, R.L., 1979, Ash-flow magmatism. Geological Society of America, Special Paper 180, 5-27.
  32. Smith, R.L. and Bailey, R.A., 1968, Resurgent cauldron: In Coats, R.R., Hay, R.L. and Anderson, C.A. (eds), Studies in Volcanology, Geological Society of America Memoir 116, 613-662.
  33. Williams, I.S., Cho, D.-L. and Kim, S.W., 2009, Geochronology, and geochemical and Nd^Sr isotopic characteristics, of Triassic plutonic rocks in the Gyeonggi Massif, South Korea: constraints onTriassic post-collisional magmatism. Lithos, 107, 239-256. https://doi.org/10.1016/j.lithos.2008.10.017
  34. Worner, G. and Schmincke, H.-U., 1984, Petrogenesis of the zoned Laacher See tephra. Journal of Petrology, 25, 836-851. https://doi.org/10.1093/petrology/25.4.836
  35. Worner, G., Beusen, J.M., Duchateau, N., Gijbels, R. and Schmincke, H.U., 1983, Trace element abundances and mineral/melt distribution coefficients in phonolites from the Laacher See volcano (Germany). Contributions to Mineralogy and Petrology, 84, 152-173. https://doi.org/10.1007/BF00371282