한국지구과학회지 (Journal of the Korean earth science society)

  • 제21권3호
  • /
  • Pages.349-358
  • /
  • 2000
  • /
  • 1225-6692(pISSN)
  • /
  • 2287-4518(eISSN)
한국지구과학회 (The Korean Earth Science Society)
권호 표지

충남지역 초염기성 암체의 지구물리학적 연구: 탄성파 속도 특성

Geophysical Study on the Ultramafic Rocks of Chungnam Province, Korea: Characteristics of Seismic Velocity

  • 서만철 (공주대학교 지질환경과) ;
  • 우영균 (공주대학교 지질환경과) ;
  • 송석환 (중부대학교 환경공학과) ;
  • Suh, Man-Cheol (Department of Geoenvironmental Science, Kongju National University) ;
  • Woo, Young-Kyun (Department of Geoenvironmental Science, Kongju National University) ;
  • Song, Suck-Hwan (Department of Environmental Engineering, Joongbu University) ;
  • Tianyao, Hao (Institute of Geophysics, Chinese Academy of Science)
  • 발행 : 2000.06.28
PDF 다운로드
⟨ 이전 논문 다음 논문 ⟩

초록

충남 일원에 분포하는 초염기성 암석과 이에 수반되는 각섬암, 편암, 편마암에 대해 탄성파 및 밀도가 실험실에서 측정되었다. 밀도측정 결과 사문암은 2.6${\sim}$2.86g/cm$^3$, 활석은 2.25${\sim}$2.81g/cm$^3$, 변성암류는 2.74${\sim}$3.07g/cm$^3$의 범위를 갖는다. 이 결과 활석은 사문암으로부터의 변성과정으로 사문암 및 각섬암보다 넓은 범위를 보였다. P파와 S파의 속도는 사문암에서 각각 5719${\sim}$6062m/s, 2898${\sim}$3351m/s 이고, 활석에서 4019${\sim}$5478m/s, 2241/${\sim}$2976m/s, 각섬암에서 5375${\sim}$6372m/s, 3042${\sim}$3625m/s, 편암에서 5290${\sim}$5499m/s, 2968${\sim}$3137m/s, 편마암에서 4788m/s, 2804m/s를 보였다. P파의 속도는 밀도가 증가함에 따라 S파의 속도보다 1.47배 빠르게 증가하였다. 탄성파 속도와 밀도 사이에 비례관계가 성립하며, 특히 밀도에 따른 P파 속도 증가율이 S파 속도증가율보다 약 1.47배 크게 나타났다. 탄성파속도의 이방분석결과 편리와 직각 방향의 속도값이 평행방향의 값보다 높았는데, 특히 변성암이 더 큰 차이를 보이는바, 이는 변성암의 형성이 지체구조성 압력의 영향으로 인한 광역변성작용에 의한 것임을 시사한다. 압력의 변화에 따른 탄성파속도 변화분석 결과 대체로 압력이 20 MPa에서 70 MPa로 증가함에 따라 변성암의 탄성파속도 증가가 다른 암석에 비하여 크게 나타났다. 재계산된 탄성파속도는 각섬암이 이 지역 하부 지각에 대한 탄성파 특성을, 편마암류 및 편암은 상부지각 암석의 탄성파 특성을 지시한다고 생각된다. 한편 사문암의 측정치는 높은 사문암화 정도를 반영하기는 하지만 상부 맨틀의 암석에 대한 탄성파의 특성을 지시한다 볼 수 있다.

Compressional and shear wave velocities (Vp and Vs) and densities have been measured for serpentinite, amphibolite, amphibole and biotite schist, and gneiss from western part of Chungnam Province at room temperature. Ranges of the density are 2.6${\sim}$2.86g/cm$^3$ for serpentinite, 2.25${\sim}$2.81g/cm$^3$ for talc, and 2.74${\sim}$3.07g/cm$^3$ for metamorphic rocks. Of these rocks, talc shows wider ranges than serpentinite and amphibolites due to its metamorphic process from serpentinite. Values of Vp and Vs are 5719${\sim}$6062m/s and 2898${\sim}$3351m/s for serpentinites, 4019${\sim}$5478m/s and 2241/${\sim}$2976m/s for talc, 5375${\sim}$6372m/s and 3042${\sim}$3625m/s for amphibolite, 5290${\sim}$5499m/s and 2968${\sim}$3137m/s for schist, and 4788m/s and 2804m/s for gneiss, respectively. Velocity of P wave increases 1.47 times faster than S wave with increase of density. The results of seismic velocity measurement show anisotropy, higher velocity across than along the schistocity of rocks, especially in metamorphic rocks. This fact indicates that there were regional metamorphism related with tectonic forces. Values of seismic velocity increase with increasing pressure from 20 MPa to 70 MPa, especially in metamorphic rocks. Overall recalculated Vp and Vs values suggest that the serpentinite indicates for upper mantle in the respects of seismic characteristics, in spite of high degree of serpentinization. In addition, those of the amphibolite do for low crust, and gneiss and schist for upper crust.

키워드

참고문헌

  1. 1:50,000 공주지질도폭 김서운;유환수;우영균
  2. 대흥지질 도폭 및 설명서 엄상호;이민성
  3. 광산지질 v.24 충남예산지역 활석광상의 성인에 대한 연구 우영균;최석원;박기화
  4. 자원환경지질 v.27 초염기성암 기원의 평안 및 대흉활석광상의 성인과 광물화학 윤상필;문희수;송윤구
  5. 암석학회지 v.3 대흉활석광상주위의 편마암류의 지화학적 특징과 공존광물의 화학적 평형 이상헌;최기주
  6. 홍성지질 도폭 및 설명서 이종혁;김성수
  7. J. Geophys. Res. v.66 The velocity of compressional waves in rocks to 10 kilobars, Part 2 Birch, F.
  8. Tectonophysics v.149 Geochemistry and petrogenesis of the Lanzo peridotite body, western Alps Bodinier, J. L.
  9. Phys. Chem. Earth. v.9 Origin of the ultramafic nodules from some kimberlites of Northern Lesotho and Monastery Mine, South Africa Boyd, F. R.;Green, D. H.;Roy, S. D.
  10. Econ. and Environ. Geol. (in submit) Genetic implications of ultramafic rocks from the Bibong area in Kyeonggi Gneiss Complex Choi, A. G.;Song, S.H.;Woo, J.K.
  11. J. Geophys. Res. v.71 Elasticity of ultrabasic rocks Christensen, N. I.
  12. Tectonyphysics v.6 Chemical changes associated with upper mantle structure Christensen, N. I.
  13. J. Geophys. Res. v.79 Compressional wave velocities in possible mantle rocks to pressures of 30 kilobars Christensen, N. I.
  14. Geol. Soc. Am. Bull. v.86 Constitution of lower continental crust based on the experimental studies of seismic velocities in granulite Christensen, N. I.;Fountain, D. M.
  15. Geol. Soc. Am. Bull. v.93 Pyroxene orientation within the upper mantle Christensen, N. I.;Lundquist, S. M.
  16. J. Geophys. Res. v.75 Effects of iron/magnesium ratio on the P and S wave velocities in olivine Chung, D. H.
  17. Geol. Soc. Am. Bull. v.82 Petrologic and Geophysical nature of serpentinites Colemann, R.G.
  18. J. Petro. v.29 Petrogenesis of ultramafic metamorphic rocks from 3800 Ma Isua supracrustal belt, Western Greenland Dymek, R. F.;Brothers, S. C.;Schiffries, C. M.
  19. Earth Planet. Sci. Lett. v.56 Exposed crosssections through the continental crust: implications for crustal structure, petrology, and evolution Founrain, D. M.;Salisbury, M. H.
  20. J. Petro. v.25 Ultramafic xenoliths from Bullenmerri and Gnotuk Maars, Victoria, Australia: petrology of sub-continental crust-mantle transition Griffin, W. L.;Wass, S. Y.;Hollis, J. D.
  21. Earth Planet. Sci. Lett. v.86 Phase transformations in a dynamical behavior of the subduction slab Irifune, T.;Ringwood, A. E.
  22. Tectonophysics v.173 Measured and calculated wave velocities for xenoliths from lower crust and upper mantle Jackson, I.;Rudnick, R.L.;O'Reilly, S. Y.;Bezant, C.
  23. Tectonophysics v.101 Laboratory wave velocity measurements on the lower crustal xenoliths from Calcutteroo, South Australia Jackson, I.;Arculus, R. J.
  24. Rev. Geophys. Space Phys. v.19 The nature of lower continental crust; inferences from geophysics, surface geology and crustal xenoliths Kay, R. W.;Kay, S. M.
  25. Bull. Seismo. Soc. Am. v.59 Upper mantle structure in the Basin and Range province, western N. America, from the apparent velocities of S-waves Kovach, R. L.;Robinson, R.
  26. Nature v.289 Upper mantle seismic anistropy and lithospheric decoupling Leven, J. H.;Jackson, I.;Ringwood, A. E.
  27. J. Geophys. Res. v.74 Velocity~density systematics for olivine spinel phases pf Mg₂SiO₄~Fe₂SiO₄ Liebermann, R.C.
  28. Geol. Soc. Amer. Bull. v.83 Diapiric emplacement of the Ronda high~temperature ultramafic intrusion, southern Spain Loomis, T. P.
  29. Nature v.285 Mantle composition derived from the composition of iherzolites Maaloe, S.;Steel, R.
  30. J. Geophys. Res. v.79 Compressional and shear wave velocities in granulite facies rocks and eclogites to 10 kilobar Manghnani, M. H.;Ramananantoandro, R.;Clark, S. P.
  31. Ophiolites and Oceanic Lithosphere, Blackwell v.13 Chemical and isotopic heterogeneities in orogenic and ophiolitic peridotites Menzies, M. A.;Gass, I.G.(ed.);Lippard, S.J.(ed.);Shelton, A.W.(ed.)
  32. Geol. Soc. Amer. Memoir no.132 Types of alpine ultramafic rocks and their implications for fossil plate interactions, studies in Earth and Space Sciences Moores, E. M.;MacGregor, I. E.;Shagam, R.(et al.)(eds.)
  33. Tectonophysics v.185 Equilibration temperatures and elastic wave velocities for upper mantle rocks from eastern Australia: Implications for the interpretation of seismological models O'Reilly, S. Y.;Jackson, I.;Bezant, C.
  34. Tectonophysics v.111 A xenolith derived geotherm for southeastern Australia and its geophysical implications O'Reilly, S. Y.;Griffin, W. L.
  35. J. Petro. v.35 Melting and melt segregation in the mantle wedge above a subduction zone: Evidence from the chromite~bearing peridoties of the Miyamori ophiolie complex, Northeastern Japan Ozawa, K.
  36. Contrib. Mineral. Petro. v.78 The origin and significance of large, tabular dunite bodies in the Trinity peridotite, northern California Quick, J. E.
  37. Metamorphic petrology Raymond, L. A.
  38. Geol. Soc. Amer, Spec. paper v.198 Composition and origin of the Kanar Melange, southern Parkistan, Melange: Their nature, Origin and Significance Sarwat, G.;DeJong, K.;Raymond, L.A.(ed.)
  39. J. Geophys. Res. v.69 Velocity of shear waves in rocks to 10 kilobars Simmons, G.
  40. J. Korean Inst. Mining Geol v.24 Supergene Chloritization and vermiculitization in Hornblende Hneiss, the Cheongyang area, Korea Song. Y. G.;Moon, H. H.
  41. Earth, Planet. Sci. Lett. v.55 Lewisian gneiss geochemistry of Archaean crustal development models Weaver, B. L.;Tarney, J.
  42. Econ. Environ. Geol. v.27 Preliminary study on ultramafic rocks from the Chungnam Province, Korea Wee, S. M.;Choi, S. G.;So, C. G.