Journal of the Geological Society of Korea (지질학회지)

The Geological Society of Korea (대한지질학회)
권호 표지
DOI QR코드

DOI QR Code

Identification of materials in principal slip zones of faults by X-ray diffraction analysis using a small amount of sample

소량의 시료의 X-선 회절분석을 통한 단층 주미끌림대의 물질분석

  • Kim, Chang-Min (Department of Geology and Research Institute of Natural Science, Gyeongsang National University) ;
  • Jeong, Jong Ok (Center for Research Facilities, Gyeongsang National University) ;
  • Gu, Dohee (Department of Geology and Research Institute of Natural Science, Gyeongsang National University) ;
  • Han, Raehee (Department of Geology and Research Institute of Natural Science, Gyeongsang National University)
  • 김창민 (경상대학교 지질과학과 및 기초과학연구소) ;
  • 정종옥 (경상대학교 공동실험실습관) ;
  • 구도희 (경상대학교 지질과학과 및 기초과학연구소) ;
  • 한래희 (경상대학교 지질과학과 및 기초과학연구소)
  • Received : 2017.11.27
  • Accepted : 2017.12.17
  • Published : 2017.12.31
⟨ Previous Next ⟩

Abstract

Fault materials in principal slip zones (PSZs), where the shear displacement is concentrated, are one of the most important factors that control the frictional properties of a fault. Thus, the identification of mineral composition of fault materials is essential to understanding the mechanical behaviors of faults. However, since the PSZ of natural faults is commonly very thin (less than a few cm or mm), special attention should be paid to the sampling and analysis of the materials in the PSZ. In this study, we designed X-ray diffraction (XRD) analyses on the fault materials taken from a narrow PSZ using a high-resolution X-ray diffractometer to examine if mineral composition can be reliably determined from a small amount of fault materials. The materials analyzed in the study were taken from about 2-cm-thick PSZ and adjacent fault core of the Yangsan fault zone, Bogyeongsa area, Pohang. Some slabs were prepared from the materials, and the powder specimens used in the XRD analyses were scraped from the slabs with a micro-drill. Given the results of the XRD analyses performed by changing the amount of the material, it follows that the minimum amount of sample needed for the reliable determination of mineral composition is estimated to be about 2 mg. The mineral compositions determined by using the 2-mg-specimens of the PSZ materials (PSZ-B and PSZ-R) and the brownish fault core material (BZ) confirm that the PSZ may be composed of different minerals from the adjacent areas. The method developed in the study may be effectively used for the materials not only in thin layers of natural fault materials but also in recovered experimental faults or in thin faults found in drilling cores from which only a small amount of material can be collected.

전단변위가 집중되는 단층핵 내부의 주미끌림대(principal slip zone, PSZ)를 구성하는 물질, 즉 단층물질(fault material)은 단층의 마찰 특성을 결정하는 가장 중요한 인자 중 하나이다. 따라서, 단층물질의 광물조성을 정확히 확인하는 것은 단층의 역학적 거동 이해를 위해 반드시 필요하다. 그러나 자연의 단층대에서 관찰되는 PSZ는 대부분 수 cm에서 수 mm 이하의 매우 좁은 폭을 가지기 때문에 PSZ를 이루는 단층물질만의 정확한 광물조성을 알기 위해서는 시료채취와 분석과정에서 특별한 주의가 필요하다. 본 연구에서는 좁은 PSZ에서 채취된 미량의 시료만으로도 단층물질의 광물조성이 쉽고 정확하게 결정될 수 있는지를 확인하기 위해 고분해능 XRD 기기를 이용한 X-선 회절분석을 시도하였다. 본 연구의 대상물질은 포항 보경사 지역의 양산단층대에서 발달하는 2 cm 폭의 PSZ와 그 주변 단층핵에서 채취되었으며, 이 물질로부터 일차적으로 슬랩을 만들고 X-선 회절분석 시료는 마이크로 드릴을 이용하여 그 슬랩으로부터 소량의 파우더를 긁어내는 방식으로 채취하였다. 시료량에 따른 고분해능 XRD기기의 정확도를 검증한 결과, 정성분석이 가능한 최소시료량은 대략 2 mg으로 측정되었다. 이것을 기준으로 PSZ 내부 단층물질들(PSZ-B, PSZ-R)과 단층핵 내부 갈색 단층물질(BZ)을 미량(2 mg) 채취하여 분석한 결과, PSZ가 인접한 물질들과는 상이한 광물조성을 가질 수 있음을 확인하였다. 본 연구를 통해 개발된 PSZ 단층물질 분석법은 기존 덩어리시료 분석법에 비해 좁은 영역에서 발달하는 단층물질 연구에 효과적이며, 전단실험으로부터 회수한 실험단층물질이나 시추코어에서 발견되는 단층물질 등 이용 가능한 시료량이 극히 제한된 상황에서의 물질연구에도 활용될 수 있을 것이다.

Keywords

Acknowledgement

Supported by : 경상대학교

References

  1. Aretusini, S., Mittempergher, S., Plumper, O., Spagnuolo, E., Gualtieri, A.F. and Di Toro, G., 2017, Production of nanoparticles during experimental deformation of smectite and implications for seismic slip. Earth and Planetary Science Letters, 463, 221-231, https://doi.org/10.1016/j.epsl.2017.01.048.
  2. Bestmann, M., Pennacchioni, G., Frank, G., Goken, M. and Wall, H., 2011, Pseudotachylyte in muscovite-bearing quartzite: Coseismic friction-induced melting and plastic deformation of quartz. Journal of Structural Geology, 33, 169-186. https://doi.org/10.1016/j.jsg.2010.10.009
  3. Carpenter, B., Marone, C. and Saffer, D., 2009, Frictional behavior of materials in the 3D SAFOD volume. Geophysical Research Letters, 36, L05302, https://doi.org/10.1029/2008GL036660.
  4. Carpenter, B., Marone, C. and Saffer, D., 2011, Weakness of the San Andreas Fault revealed by samples from the active fault zone. Nature Geoscience, 4, 251-254. https://doi.org/10.1038/ngeo1089
  5. Chae, B.-G. and Chang, T.W., 1994, Movement history of Yangsan fault and its related fractures at Chongha-Yongdok area, Korea. Journal of the Geological society of Korea, 30, 379-394 (in Korean with English abstract).
  6. Chester, F.M. and Chester, J.S., 1998, Ultracataclasite structure and friction processes of the Punchbowl fault, San Andreas system, California. Tectonophysics, 295, 199-221. https://doi.org/10.1016/S0040-1951(98)00121-8
  7. Choo, C.O. and Chang, T.W., 2000, Characteristics of clay minerals in gouges of the Dongrae fault, Southeastern Korea, and implications for fault activity. Clays and clay minerals, 48, 204-212. https://doi.org/10.1346/CCMN.2000.0480206
  8. Collettini, C., Carpenter, B.M., Viti, C., Cruciani, F., Mollo, S., Tesei, T., Trippetta, F., Valoroso, L. and Chiaraluce, L., 2014, Fault structure and slip localization in carbonate-bearing normal faults: An example from the Northern Apennines of Italy. Journal of Structural Geology, 67, 154-166, http://dx.doi.org/10.1016/j.jsg.2014.07.017.
  9. De Paola, N., Collettini, C., Faulkner, D.R. and Trippetta, F., 2008, Fault zone architecture and deformation processes within evaporitic rocks in the upper crust. Tectonics, 27, TC4017.
  10. De Paola, N., Hirose, T., Mitchell, T., Di Toro, G., Viti, C. and Shimamoto, T., 2011, Fault lubrication and earthquake propagation in thermally unstable rocks. Geology, 39, 35-38. https://doi.org/10.1130/G31398.1
  11. Di Toro, G., Goldsby, D.L. and Tullis, T.E., 2004, Friction falls towards zero in quartz rock as slip velocity approaches seismic rates. Nature, 427, 436-439. https://doi.org/10.1038/nature02249
  12. Faulkner, D.R., Lewis, A.C. and Rutter, E.H., 2003, On the internal structure and mechanics of large strike-slip fault zones: field observations of the Carboneras fault in southeastern Spain. Tectonophysics, 367, 235-251, http://dx.doi.org/10.1016/S0040-1951(03)00134-3.
  13. Fujimoto, K. and Sato, K., 2017, Studies of montmorillonite mechanochemically decomposed at different water contents. Geomaterials, 7, 41-50. https://doi.org/10.4236/gm.2017.72004
  14. Han, R., Hirose, T., Jeong, G.Y., Ando, J. and Mukoyoshi, H., 2014, Frictional melting of clayey gouge during seismic fault slip: Experimental observation and implications. Geophysical Research Letters, 41, 5457-5466, https://doi.org/10.1002/2014GL061246.
  15. Han, R., Hirose, T., Shimamoto, T., Lee, Y. and Ando, J., 2011, Granular nanoparticles lubricate faults during seismic slip. Geology, 39, 599-602. https://doi.org/10.1130/G31842.1
  16. Han, R., Shimamoto, T., Ando, J. and Ree, J.-H., 2007a, Seismic slip record in carbonatebearing fault zones: an insight from high-velocity friction experiments on siderite gouge. Geology, 35, 1131-1134. https://doi.org/10.1130/G24106A.1
  17. Han, R., Shimamoto, T., Hirose, T., Ree, J.-H. and Ando, J., 2007b, Ultralow friction of carbonate faults caused by thermal decomposition. Science, 316, 878-881. https://doi.org/10.1126/science.1139763
  18. Hayward, K.S., Cox, S.F., Fitz Gerald, J.D., Slagmolen, B.J.J., Shaddock, D.A., Forsyth, P.W.F., Salmon, M.L. and Hawkins, R.P., 2016, Mechanical amorphization, flash heating, and frictional melting: Dramatic changes to fault surfaces during the first millisecond of earthquake slip. Geology, 44, 1043-1046, http://dx.doi.org/10.1130/g38242.1.
  19. Hirono, T., Asayama, S., Kaneki, S. and Ito, A., 2016, Preservation of amorphous ultrafine material: A proposed proxy for slip during recent earthquakes on active faults. Scientific Reports, 6, 36536, http://dx.doi.org/10.1038/srep36536.
  20. Ikari, M.J., Marone, C. and Saffer, D.M., 2011, On the relation between fault strength and frictional stability. Geology, 39, 83-86, http://dx.doi.org/10.1130/g31416.1.
  21. Ishikawa, T., Tanimizu, M., Nagaishi, K., Matsuoka, J., Tadai, O., Sakaguchi, M., Hirono, T., Mishima, T., Tanikawa, W., Lin, W., Kikuta, H., Soh, W. and Song, S.-R., 2008, Coseismic fluid-rock interactions at high temperatures in the Chelungpu fault. Nature Geoscience, 1, 679, http://dx.doi.org/10.1038/ngeo308.
  22. Janssen, C., Wirth, R., Lin, A. and Dresen, G., 2013, TEM microstructural analysis in a fault gouge sample of the Nojima Fault Zone, Japan. Tectonophysics, 583, 101-104. https://doi.org/10.1016/j.tecto.2012.10.020
  23. Janssen, C., Wirth, R., Rybacki, E., Naumann, R., Kemnitz, H., Wenk, H.R. and Dresen, G., 2010, Amorphous material in SAFOD core samples (San Andreas Fault): Evidence for crush-origin pseudotachylytes? Geophysical Research Letters, 37, L01303, http://dx.doi.org/10.1029/2009GL040993.
  24. Kim, C.-M., Han, R., Jeong, G.Y., Jeong, J.O. and Son, M., 2016, Internal structure and materials of the Yangsan fault, Bogyeongsa area, Pohang, South Korea. Geosciences Journal, 20, 1-15, http://dx.doi.org/10.1007/s12303-016-0019-8.
  25. Kirkpatrick, J., Rowe, C., White, J. and Brodsky, E., 2013, Silica gel formation during fault slip: Evidence from the rock record. Geology, 41, 1015-1018. https://doi.org/10.1130/G34483.1
  26. Kuo, L.-W., Song, S.-R., Suppe, J. and Yeh, E.-C., 2016, Fault mirrors in seismically active fault zones: A fossil of small earthquakes at shallow depths. Geophysical Research Letters, 43, 1950-1959, http://dx.doi.org/10.1002/2015GL066882.
  27. Lee, S.K., Han, R., Kim, E.J., Jeong, G.Y., Khim, H. and Hirose, T., 2017, Quasi-equilibrium melting of quartzite upon extreme friction. Nature Geoscience, 10, 436, http://dx.doi.org/10.1038/ngeo2951.
  28. Lin, A., 1994, Glassy pseudotachylyte veins from the Fuyun fault zone, northwest China. Journal of Structural Geology, 16, 71-83, http://dx.doi.org/10.1016/0191-8141(94)90019-1.
  29. Oohashi, K., Hirose, T. and Shimamoto, T., 2011, Shear-induced graphitization of carbonaceous materials during seismic fault motion: Experiments and possible implications for fault mechanics. Journal of Structural Geology, 33, 1122-1134, http://dx.doi.org/10.1016/j.jsg.2011.01.007.
  30. Scuderi, M.M., Collettini, C., Viti, C., Tinti, E. and Marone, C., 2017, Evolution of shear fabric in granular fault gouge from stable sliding to stick slip and implications for fault slip mode. Geology, 45, 731-734, http://dx.doi.org/10.1130/g39033.1.
  31. Sibson, R.H., 2003, Thickness of the Seismic Slip Zone. Bulletin of the Seismological Society of America, 93, 1169-1178, http://dx.doi.org/10.1785/0120020061.
  32. Siman-Tov, S., Aharonov, E., Sagy, A. and Emmanuel, S., 2013, Nanograins form carbonate fault mirrors. Geology, 41, 703-706. https://doi.org/10.1130/G34087.1
  33. Smith, S.A.F., Billi, A., Toro, G.D. and Spiess, R., 2011, Principal Slip Zones in Limestone: Microstructural Characterization and Implications for the Seismic Cycle (Tre Monti Fault, Central Apennines, Italy). Pure and Applied Geophysics, 168, 2365-2393, http://dx.doi.org/10.1007/s00024-011-0267-5.
  34. Viola, G., Scheiber, T., Fredin, O., Zwingmann, H., Margreth, A. and Knies, J., 2016, Deconvoluting complex structural histories archived in brittle fault zones. Nature Communications, 7, 13448, http://dx.doi.org/10.1038/ncomms13448.
  35. Viti, C., 2011, Exploring fault rocks at the nanoscale. Journal of Structural Geology, 33, 1715-1727. https://doi.org/10.1016/j.jsg.2011.10.005
  36. Wirth, R., 2009, Focused Ion Beam (FIB) combined with SEM and TEM: Advanced analytical tools for studies of chemical composition, microstructure and crystal structure in geomaterials on a nanometre scale. Chemical Geology, 261, 217-229, https://doi.org/10.1016/j.chemgeo.2008.05.019.
  37. Yund, R.A., Blanpied, M.L., Tullis, T.E. and Weeks, J.D., 1990, Amorphous material in high strain experimental fault gouges. Journal of Geophysical Research: Solid Earth, 95, 15589-15602, http://dx.doi.org/10.1029/JB095iB10p15589.

Cited by

  1. 밀양 국전광산의 녹-청색 구리-아연 수화황산염 광물 vol.51, pp.6, 2017, https://doi.org/10.9719/eeg.2018.51.6.473
  2. Structures and deformation characteristics of the active fault, Hwalseongri area, Gyeongju, Korea vol.56, pp.6, 2020, https://doi.org/10.14770/jgsk.2020.56.6.703
  3. 동시베리아해 망가니즈단괴의 산화망가니즈광물 반정량 분석 vol.33, pp.4, 2017, https://doi.org/10.22807/kjmp.2020.33.4.427
  4. Deformation bands in the Eoil Basin, Gyeongju, Korea: Field occurrence and structural characteristics vol.57, pp.3, 2021, https://doi.org/10.14770/jgsk.2021.57.3.275
  5. Geological Records of Coseismic Shear Localization Along the Yangsan Fault, Korea vol.126, pp.8, 2017, https://doi.org/10.1029/2020jb021393