The Journal of the Petrological Society of Korea (암석학회지)

The Petrological Society of Korea (한국암석학회)
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Textural and Genetic Implications of Type II Xenoliths Enclosed in Basaltic Rocks from Jeju Island

제주도 현무암에 포획된 Type II 포획암: 성인과 조직적 특성

  • Yu, Jae-Eun (Division of Earth Environmental System, Pusan National University) ;
  • Yang, Kyoung-Hee (Division of Earth Environmental System, Pusan National University) ;
  • Hwang, Byoung-Hoon (Division of Earth Environmental System, Pusan National University) ;
  • Kim, Jin-Seop (Division of Earth Environmental System, Pusan National University)
  • 유재은 (부산대학교 지구환경시스템학부) ;
  • 양경희 (부산대학교 지구환경시스템학부) ;
  • 황병훈 (부산대학교 지구환경시스템학부) ;
  • 김진섭 (부산대학교 지구환경시스템학부)
  • Published : 2009.09.30
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Abstract

Ultramafic xenoliths from southeastern part of Jeju Island can be grouped into two types: Type I and Type II. Type I xenoliths are magnesian and olivine-rich peridotite (mg#=89-91), which are commonly found at the outcrop. Most previous works have been focused on Type I xenoliths. Type II xenoliths, consisting of olivine, orthopyroxene and clinopyroxene with higher Fe and Ti components (mg#=77-83) and lower Mg, Ni, Cr, are reported in this study. They are less common with a more extensive compositional range. The studied Type II xenoliths are wehrlite, olivine-clinopyroxenite, olivine websterite, and websterite. They sometimes show ophitic textures in outcrops indicating cumulate natures. The textural characteristics, such as kink banding and more straight grain boundaries with triple junctions, are interpreted as the result of recrystallization and annealing. Large pyroxene grains have exsolution textures and show almost the same major compositions as small exsolution-free pyroxenes. Although the exsolution texture indicates a previous high-temperature history, all mineral phases are completely reequilibrated to some lower temperature. Orthopyroxenes replacing clinopyroxene margin or olivine indicate an orthopyroxene enrichment event. Mineral phases of Type II are compared with Type I xenoliths, gabbroic xenoliths, and the host basalts. Those from Type II xenoliths show a distinct discontinuity with those from Type I mantle xenoliths, whereas they show a continuous or overlapping relation with those from gabbroic xenoliths and the host basalts. Our petrographic and geochemical results suggest that the studied type II xenoliths appear to be cumulates derived from the host magma-related system, being formed by early fractional crystallization, although these xenoliths may not be directly linked to the host basalt.

제주도 동남부에 산출되는 초염기성 포획암은 두 그룹, Type I과 Type II로 분류되어진다. Type I 포획암은 Mg 성분이 높은 광물(mg#=89-91)로 구성된 페리도타이트로서 노두에서 비교적 흔하게 발견된다. 제주도 초염기성 포획암에 대한 대부분의 연구는 Type I 맨틀포획암에 관한 것이다. 반면에 Type II 포획암은 상대적으로 Mg, Ni, Cr성분은 낮고 Fe, Ti 성분이 높은 감람석, 사방휘석, 단사휘석(mg#=77-83)으로 이루어져 있다. Type II 포획암의 성분은 월라이트-감람석 단사휘석암-감람석 웹스터라이트-웹스터라이트이며, Ti이 풍부한 단사휘석을 가지는 것이 특징이다. Type II 포획암은 노두에서 포이킬리틱한 조직을 나타내어 규뮬레이트의 특성을 보인다. Type II 포획암에 나타나는 삼중점과 킹크밴딩, 직선적인 입자경계 조직은 Type II 포획암이 열에 의해 야기되는 정적재결정작용과 어닐링을 경험하였음을 지시한다. 조립질의 사방휘석과 단사휘석은 용리엽리를 보이며(고온형 휘석), 세립질의 휘석은 용리엽리를 보이지 않는(저온형 휘석) 특성을 보이지만 이들의 주성분조성은 거의 유사하여 저온에서 화학적 재평형이 완전히 이루어졌음을 지시한다. 단사휘석과 감람석의 가장자리를 사방휘석이 교대치환하고 있어 사방휘석의 부화작용(enrichment)이 일어났음을 지시한다. 같은 노두에서 발견되는 Type I 맨틀포획암, 반려암질포획암, 모암인 현무암내의 결정들과 비교해보면 Type II 포획암의 주성분원소 조성은 Type I 맨틀포획암과는 뚜렷하게 단절되는 불연속을 형성하지만 반려암 질포획암과 모암인 현무암과는 연속적인 경향을 보인다. 이러한 조직적 특성과 주성분원소 성분조성은 Type II 포획암이 현재의 모암인 현무암과는 직접적인 관련성이 없다할지라도 제주도를 형성한 마그마계의 일부분으로 분별결정작용에 의한 집적암(cumulates) 기원임을 제시한다.

Keywords

References

  1. 고기원, 박윤석, 박언배, 2004, 제주도 동부지역의 지하 지질분포와 $^{40}$Ar_$^{39}$Ar 연대. 2004 대한지질학회 춘계학술답사, 대한지질학회, 29-50
  2. 남복현, 양경희, 엄영보, Karoly Hidas, Csaba Szabo, 2007, 제주도 현무암과 맨틀포획암에 산출되는 함수광물의 중요성， 2007 한국광물학회. 한국암석학회 공동학술발표회 논문집, 176-179
  3. 박기화, 2004, 제주도 형성사, 2004 대한지질학회 춘계학술답사, 대한지질학회, 1
  4. 박준범, 권성택, 1996, 제주도의 솔리아이트 화산활동. 암석학회지, 5, 66-83
  5. 박준범, 박기화, 조등룡, 고기원, 1999, 제주도 제 4기 화산암류의 암석화학적 분류. 지질학회지, 35, 253-264
  6. 엄영보, 양경희, 남복현, 황병훈, 김진섭, 2007, 제주도 알칼리 현무암에 포획된 반려암질 포획암, 광물학회지, 20, 103-114
  7. 윤성효, 고정선, 안지영, 1998, 제주도 동부 알칼리 현무암내 스피넬-레졸라이트 포획체의 연구, 자원환경지질학회지, 31, 447-458
  8. 윤성효, 고정선, 박정미, 2002, 제주도 남동부 태흥리 용암에 대한 암석학적 연구. 암석학회지, 11, 17-29
  9. 이문원, 원종관, 이동영, 박계현, 김문섭, 1994, 제주도 화산암류의 화산층서 및 암석학적 연구. 지질학회지, 30, 521-541
  10. 양경희, 남복현, 김진섭, Szab, C., 2009, 제주도 현무암에 포획된 세립질 맨틀 페리도타이트 포획암의 조직적 특성. 광물학회지, 22, 1-11
  11. 진명식, 2004, 한국의 화성활동. 한국암석학회 추계학술심포지엄 논문집, 한국의 화성활동, 한국암석학회, 103-104
  12. 황재하, 송교영, 2003, 제주도의 지구조운동, 제1회 학술심포지엄, 제주화산연구소 개소기념, 제주화산연구소, 1-6
  13. Allegre, C J. and Turcotte, D.L., 1986, Implications of a two-component marble-cake mantle. Nature, 323, 123-127 https://doi.org/10.1038/323123a0
  14. Chen, S., O'Reilly, S.Y., Zhou, x., William, L.G., Zhang, G., Sun, M. and Feng, J., Zhang, M., 2001, Thermal and petrological structure of the lithosphere beneath Hannuoba, Sino-Korean craton, China: evidence from xenoliths Lithos, 56, 267-301 https://doi.org/10.1016/S0024-4937(00)00065-7
  15. Choi, S.H., Lee, J.l., Park, CH. and Moutte, J., 2002, Geochemistry of peridotite xenoliths in alkali basalts from Jeju Island, Korea, The Island Arc, 11, 221-235 https://doi.org/10.1046/j.1440-1738.2002.00367.x
  16. Frey, FA and Prinz, M., 1978, Ultramafic inclusions from San Carlos, Arizona; petrologic and geochemical data bearing on their petrogenesis. Earth and Planetary Science Letters 38, 129-178 https://doi.org/10.1016/0012-821X(78)90130-9
  17. Hamdy, A.M., Park P.H., Lim H.C. and Park K.D., 2004, Present-day relative displacements between the Jeju Island and the Korean peninsula as seen from GPS observations. Earth Planets Space, 56, 927-931 https://doi.org/10.1186/BF03352540
  18. Irving, A.J., 1974, Megacrysts from the newer basalts and other basaltic rocks of southeastern Australia. Geol. Soc. Am. Bull., 85, 1503-1514 https://doi.org/10.1130/0016-7606(1974)85<1503:MFTNBA>2.0.CO;2
  19. Hidas, K., Falus, G, Szabo, C, Szabo, PJ., Kovacs, I. and Foldes, T., 2007, Geodynamic implications of flattened tabular equigranular textured peridotites from the BakonyBalaton Highland Volcanic Field (Western Hungary). Journal of Geodynamics, 43, 484-503 https://doi.org/10.1016/j.jog.2006.10.007
  20. Kim, K.H., Nagao, K., Suzuki, K., Tanaka, T. and Park, E.J., 2003, Evidences of the presence of old continental basement in Jeju volcanic Island, South Korea, revealed by Radiometric ages and Nd-Sr isotopes of granitic rocks. Journal of Geochemical Exploration, 36, 421-441
  21. Kovacs, I., Zajacz, Z. and Szabo, C., 2004, Type-II xenoliths and metasomatism beneath the Nograd-Gomor volcanic field, Carpathian-Pannonian region (northern Hungarysouthern Slovakia). Tectonophysics, 393. 139-161 https://doi.org/10.1016/j.tecto.2004.07.032
  22. Hidas, K., Falus, G, Szabo, C., Szabo, P.J., Kovacs, I. and Foldes, T., 2007, Geodynamic implications of flattened tabular equigranular textured peridotites from the BakonyBalaton Highland Volcanic Field (Western Hungary). Journal of Geodynamics, 43, 484-503 https://doi.org/10.1016/j.jog.2006.10.007
  23. Lee, M.W, 1982, Petrology and geochemistry of Jeju volcanic island, Korea. The Science Report of the Tohoku Imperial University Section SeriesIII, 15, 177-256
  24. Lee, S.R and Walker, R.J., 2006, Re-Os isotope systematics of mantle xenoliths from South Korea: Evidence for complex growth and loss of lithospheric mantle beneath East Asia. Chem. Geol., 231, 90-101 https://doi.org/10.1016/j.chemgeo.2006.01.003
  25. Lloyd, G.E., Farmer, A.B. and Mainprice, D., 1997, Misorientation analysis and orientation of subgrain and grain boundaries. Tectonophysics, 279, 55-78 https://doi.org/10.1016/S0040-1951(97)00115-7
  26. McBirney R.B., 1993, Igneous petrology (2nd ed), Jones and Bartlett, 508p
  27. Mercier, J.C.C. and Nicolas, A, 1975, Textures and fabrics of upper-mantle peridotites as illustrated by xenoliths form basalts. Journal of Petrology, 16, 454-487 https://doi.org/10.1093/petrology/16.1.454
  28. Mukasa, S.B. and Shervais, J.W, 1999, Growth of subcontinental lithosphere: evidence from repeated dike injections in the Balmuccia lherzolite massif, Italian Alps. Lithos, 48
  29. Passchier, C.W and Trouw, R.A.J., 1996, Microtectonics. Springer-Verlag, Berlin, 289p
  30. Sachs, P.M. and Hansteen, H.T., 2000, Pleistocene underplating and metasomatism of the lowercontinental crust: a xenolith study. J. Petrol., 41, 331-356 https://doi.org/10.1093/petrology/41.3.331
  31. Tatsumi Y, Shukuno H., Yoshikawa M., Chang Q., Sato K. and Lee M.W, 2005, The petrology and geochemistry of volcanic rocks on Jeju Island: Plume magmatism along the Asian continental margin. Journal of Petrology, 46, 523-553 https://doi.org/10.1093/petrology/egh087
  32. Vauchez, A. and Garrido, C.J., 2001, Seismic properties of an asthenospherized lithospheric mantle: constraints from lattice preferred orientations in peridotite from the Ronda massif. Earth Planet. Sci. Lett., 192, 235-249 https://doi.org/10.1016/S0012-821X(01)00448-4
  33. Wilson, M., 1989, Igneous petrogenesis. Unwin Hyman, London, 466p
  34. Winter, J.D., 2001, Igneous and metamorphic petrology. Prentice Hall, New Jersey, 697p
  35. Xu, X, Oreilly, S.Y, Griffm, W.L., Zhou, X. and Huang, X, 1998, The nature of the Cenozoic lithosphere at Nushan, Eastern China. In Flower M.F.J., Chung S.L., Lo, C.H. and Lee T.Y(eds.), Mantle dynamics and plate interactions in east Asia, Geodynamics Series, 27, 167-95
  36. Xu, Y.G, Menzies, M.A, Matthew, F., Huang, X.L., Liu, Y and Chen, X.M., 2003, 'Reactive' harzburgites from Huinan, NE China: Products of the lithosphere-asthenosphere interaction during lithospheric thinning? Geochimica et Cosmochirmca Acta, 67, 487-505 https://doi.org/10.1016/S0016-7037(02)01089-X
  37. Yang K., 2004, Fluid and meIt inclusions trapped in xenoliths from the lower crust/upper mantle beneath Jeju Island (I): A preliminary study. Petorlogical Society of Korea, 13, 34-45
  38. Zoltan, Z., Kovacs, I., Szabo, e., Halter, W and Pettke, T., 2007, Evolution of Mafic Alkaline Melts Crystallized in the Uppermost Lithospheric Mantle: a Melt Inclusion Study of Olivine-Clinopyroxenite Xenoliths, Northern Hungary. Journal of Petrology, 48, 853-883 https://doi.org/10.1093/petrology/egm004