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Authigenic chlorites: problems with chemical analysis and structural formula calculations

  • C. D. Curtis (a1), B. J. Ireland (a1), J. A. Whiteman (a1), R. Mulvaney (a1) and C. K. Whittle (a1)...

Abstract

Analytical transmission electron microscopy was applied to some authigenic chlorites occurring as grain coatings in sandstones. Compositional variation proved to be relatively slight: all were magnesian chamosites. The coating chlorites were often intimately mixed with extremely fine-grained (0·01–0·2 µm) hematite but analytical ‘contamination’ was avoided because of the very high resolution of both observation (spot location) and analysis. One example of a water-sensitive (‘swelling chlorite’) coating was also studied. This proved to have a very much more variable composition even within a single section. The coating appeared to include both chloritic and vermiculitic components. The effect of this on structural formulae is discussed and a model proposed in which the ‘talc’ layer may be common to both components.

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References

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Bailey, S.W. (1980) Summary of recommendations of AIPEA Nomenclature Committee. Clay Miner. 15, 8593.
Bain, D.C. & Russell, J.D. (1981) Swelling minerals in a basalt and its weathering products from Morvern, Scotland: II. Swelling chlorite. Clay Miner. 16, 203212.
Boles, J.R. & Franks, S.G. (1979) Clay diagenesis in Wilcox Sandstones of Southwest Texas. J. Sed. Pel. 49, 5570.
Brindley, G.W. (1961) Chlorite minerals. Pp. 242296 in: The X-ray Identification and Crystal Structures of Clay Minerals (Brown, G., editor). Mineralogical Society, London.
Cliff, G. & Lorimer, G.W. (1975) The quantitative analysis of thin specimens. J. Microscopy 103, 203207.
Deer, W.A., Howie, .A. & Zussman, J. (1962) Rock Forming Minerals. Volume 3: Sheet Silicates. Longmans, London.
Doig, P., Lonsdale, D. & Flewitt, P.E.J. (1980) The spatial resolution of X-ray microanalysis in the scanning transmission electron microscope. JEOL News 18(1), 28.
Foscolos, A.E. & Powell, T.G. (1979) Catagenesis in shales and occurrence of authigenic clays in sandstones, North Sabine H-49 well, Canadian Arctic Islands. Can. J. Earth Sci. 16, 13091314.
Hayes, J.B. (1970) Polytypism of chlorite in sedimentary rocks. Clays Clay Miner. 18, 285306.
Hutcheon, I., Oldershaw, A. & Ghent, E.D. (1980) Diagenesis of Cretaceous sandstones of the Kootenay Formation at Elk Valley (southeastern British Columbia) and Mt. Allan (southwestern Alberta). Geochim. Cosmochim. Acta 44, 14251435.
Iijima, A. & Matsumoto, R. (1982) Berthierine and chamosite in coal measures of Japan. Clays Clay Miner. 30, 264274.
Ireland, B.J. (1982) Transmission electron microscopy of authigenic clay minerals. PhD thesis, University of Sheffield.
Ireland, B.J., Curtis, C.D. & Whiteman, J.A. (1983) Compositional variation within some glauconites and illites and implications for their stability and origins. Sedimentology 30, 769786.
Odin, G.S. & Matter, A. (1981) De glauconarium origine. Sedimentology 28, 611641.
Phakey, P.P., Curtis, C.D. & Oertel, G. (1972) Transmission electron microscopy of fine-grained phyllosilicates in ultra-thin rock sections. Clays Clay Miner. 20, 193197.
Veblen, D.R. (1983) Microstructure and mixed-layering in intergrown wonesite, chlorite, talc, biotite and kaolinite. Am. Miner. 68, 566580.

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