Mineralogical Characteristics and Genetic Environment of Zeolitic Bentonite in Yeongil Area

영일 지역 제올라이트질 벤토나이트의 광물특성 및 생성환경

  • 노진환 (강원대학교 지질학과) ;
  • 고상모 (한국지질자원연구원 지질기반정보연구부)
  • Published : 2004.06.01


A zeolitic bentonite, which exhibits whitish appearance and contains considerable amounts (nearly 〉 5%) of zeolites, frequently occurs as thin beds less than 1 m in Yeongil area. The bentonites are mostly found in closely association with zeolite beds in the Nuldaeri Tuff and Coal-bearing formations of the Janggi Croup. A discordant occurrence of the bentonite against the bedding plane is also locally found. Montmorillonite, the major mineral constituent of the bentonite, is mostly associated with clinoptilolite as a zeolite. However, instead of clinoptilolite, mordenite is sometimes included in the case of more silicic bentonite, and heulandite in the less silicic one. It is characteristic that the mordenite is accompanied by lots of opal-CT in the silicic bentonite. SEM observations characteristically indicate that these authigenic phases, especially the montmorillonite and zeolite, nearly coexist as mixtures not forming a fine-scale zoning. The zeolitic bentonite seems to be formed in the comparatively silicic pore fluid at the alkaline condition accompanying pH fluctuation Compared to the zeolite-free normal bentonite, the zeolitic types exhibit somewhat higher REE abundance. These chemical characteristics, together with modes of occurrences and authigenic mineral associations, may suggest that the zeolitic bentonite is not merely diagenetic products and a possible hydrothermal alteration could not be excluded in the bentonite genesis.


  1. 노진환 (2000) 벤토나이트의 광물학적 특성과 품위 및 품질 평가. 제 1회 산업광물심포지움 논문집: 벤토나이트와 그 응용. 산업광물은행, 16-29.
  2. 노진환 (2001) 국내산 제올라이트의 부가가치 향상을 위한 광물특성 평가방안. 광물과산업, 14-1, 1-17.
  3. 노진환 (2002) 국내산 벤토나이트의 광물학적 및 암석학적 측징과 그 성인적 의미. 지질학회지, 38, 441-445.
  4. 노진환 (2003) 국내산 벤토나이트에 대한 응용광물학적 특성 평가 (II): 광물학적 특징, 체표면적 및 유변학적 특성과 그 연계성. 한국광물학회지, 16, 33-47.
  5. 노진환 (2004) 규질 이암으로부터 유기 스멕타이트의 저온 수열합성. 한국광물학회지, 17, 49-59.
  6. Barrer, R.M. (1982) Hydrothermal Chemistry of Zeolites. Academic press, London-New York, 360p.
  7. Chang, L.L.Y. (2002) Industrial Mineralogy: Materials, Processes, and Uses. Prentice Hall, 472p.
  8. Dibble, W.E. and Tiller, W.A. (1981) Kinetic model of zeolite paragenesis in tuffaceous sediments. Clays and Clay Minerals, 29, 323-330.
  9. Faure, G. (1991) Principles and Application of Inorganic Geochemistry. McMillan Publishing Co., New York-Toronto-Oxford, 626p.
  10. Grim, R.E. and Guven, N. (1978) Bentonites: Geology, Mineralogy, Properties and Uses. Developments in Sedimentology 24, Elsevier, Amsterdam-Oxford-New York, 256p.
  11. Mariner, R.H. and Surdam, R.C. (1970) Alkalinity and formation of zeolites in saline and alkaline lakes. Science, 170, 977-980.
  12. Noh, J.H. and Boles, J.R. (1989) Diagenetic alteration of perlite in the Guryongpo area, Republic of Korea. Clays and Clay Minerals, 37, 47-58.
  13. Rietveld, H.M. (1969) A profile refinement method for nuclear and magnetic structures. Journal Applied Crystallography, 2, 65-71.
  14. Sheppard, R.L. and Hay, R.L. (2001) formation of zeolites in open hydrologic systems. In: Bish, D.L. and Ming, D.W. (eds.), Natural Zeolites: Occurrence, Properties, Application. Mineralogical Society of America, 261-275.
  15. Tateiwa, I. (1924) Geological atlas of Chosen, Ennich and Choyo Sheets. Geological Map, Korea, 2, 42 p.
  16. Taylor, J.C. (1991) Computer programs for standardless quantitative analysis of minerals using the full powder diffraction profile. Powder Diffraction, 6, 2-9.
  17. Taylor, .J.C. and Matulis, C.E. (1994) A new method for Rietveld clay analysis. Part 1. Use of a universal measured standard profile for Rietveld quantification of montmorillonite. Powder Diffraction, 9, 119-123.