Abstract
This study presents a mathematical formalism describing diffraction effects from periodic and mixed-layer minerals in which the outer surface layers of crystals possibly differ from layers forming the core of the crystals. The X-ray diffraction (XRD) patterns calculated for structure models of chlorite and irregular chlorite-smectites terminated on both sides of the crystals by either brucite-like sheets or 2:1 layers show the strong influence that different outer surface layers have on the distribution of basal reflection intensities. Simulation of the experimental XRD patterns from two chlorite samples having different Fe contents shows that in these two samples the chlorite crystals were terminated by brucite-like sheets on both sides. In contrast, crystals in a corrensite sample were terminated by water molecules and exchangeable cations. The nature of diffraction effects due to outer surface layers is discussed.
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Claret, F., Bauer, A., Schafer, T., Griffault, L. and Lanson, B. (2002) Experimental investigation of the interaction of clays with high-pH solutions: A case study from the Callovo-Oxfordian formation, Meuse-Haute Marne underground laboratory (France). Clays and Clay Minerals, 50, 633–646.
Claret, F., Sakharov, B.A., Drits, V.A., Velde, B., Meunier, A., Griffault, L. and Lanson, B. (2004) Clay minerals in the Meuse-Haute Marne underground laboratory (France): Possible influence of organic matter on clay mineral evolution? Clays and Clay Minerals, 52, 515–532.
Drits, V.A. and Sakharov, B.A. (1976) X-ray Structure Analysis of Interstratified Minerals. Nauka, Moscow, 256 pp. (in Russian).
Drits, V.A. and Smoliar-Zvyagina, B.B. (1992) Relations between unit-cell parameters and cation composition of sheet silicates. II. Trioctahedral chlorites. Geologica Carpathica — Clays, 1, 35–40.
Drits, V.A. and Tchoubar, C. (1990) X-ray Diffraction by Disordered Lamellar Structures. Springer Verlag, Berlin, 371 pp.
Drits, V.A., Kameneva, M.Yu., Sakharov, B.A., Dainyak, L.G., Tsipursky, S.I., Smoliar-Zvyagina, B.B., Bookin, A.S. and Salyn, A.L. (1993) Problems of Determination of the Actual Structure of Glauconites and Related Fine-dispersed Minerals. Nauka, Novosibirsk, 200 pp. (in Russian).
Drits, V.A., Sakharov, B.A., Lindgreen, H. and Salyn, A.L. (1997a) Sequential structure transformation of illite-smectite-vermiculite during diagenesis of Upper Jurassic shales from the North Sea and Denmark. Clay Minerals, 32, 351–371.
Drits, V.A., Środoń, J. and Eberl, D.D. (1997b) XRD measurement of mean crystallite thickness of illite and illite/smectite: Reappraisal of the Kübier index and the Scherrer equation. Clays and Clay Minerals, 45, 461–475.
Kakinoki, J. and Komura, Y. (1952) Intensity of X-ray diffraction by one dimensionally disordered crystals. I: General derivation in the case of the ‘Reichweite’ S=0 and 1. Journal of the Physical Society of Japan, 7, 30–35.
Kakinoki, J. and Komura, Y. (1954a) Intensity of X-ray diffraction by one-dimensionally disordered crystals. The close packed structure. Journal of the Physical Society of Japan, 9, 177–183.
Kakinoki, J. and Komura, Y. (1954b) Intensity of X-ray diffraction by one dimensionally disordered crystals. II: General derivation in the case of the correlation range S= 2. Journal of the Physical Society of Japan, 9, 169–176.
Kakinoki, J. and Komura, Y. (1965) Diffraction by a one-dimensionally disordered crystal. I: The intensity equation. Acta Crystallographica, 19, 137–147.
Lindgreen, H., Drits, V.A., Sakharov, B.A., Salyn, A.L., Wrang, P. and Dainyak, L.G. (2000) Illite-smectite structural changes during metamorphism in black Cambrian Alum shales from the Baltic area. American Mineralogist, 85, 1223–1238.
Ma, C. and Eggleton, R.A. (1999) Surface layer types of kaolinite: high resolution transmission electron microscopy study. Clays and Clay Minerals, 47, 181–191.
Moore, D.M. and Reynolds, R.C. (1989) X-ray Diffraction and the Identification and Analysis of Clay Minerals. Oxford University Press, Oxford, 332 pp.
Plançon, A. (1981) Diffraction by layer structures containing different kinds of layers and stacking faults. Journal of Applied Crystallography, 14, 300–304.
Plançon, A. (2002) New modeling of X-ray diffraction by disordered lamellar structures, such as phyllosilicates. American Mineralogist, 87, 1672–1677.
Plançon, A. (2003) Modelling X-ray diffraction by lamellar structures composed of electrically charged layers. Journal of Applied Crystallography, 36, 146–153.
Plançon, A. and Tchoubar, C. (1976) Etude des fautes d’empilement dans les kaolinites partiellement désordonnées. Journal of Applied Crystallography, 9, 279–285.
Reynolds, R.C. (1967) Interstratified clay system: calculation of the total one-dimensional diffraction function. American Mineralogist, 52, 661–672.
Reynolds, R.C. (1980) Interstratified clay minerals. Pp. 249–303 in: Crystal Structures of Clay Minerals and Their X-ray Identification (G.W. Brindley and G. Brown, editors). Monograph 5, Mineralogical Society, London.
Reynolds, R.C. (1986) The Lorentz factor and preferred orientation in oriented clay aggregates. Clays and Clay Minerals, 34, 359–367.
Sakharov, B.A., Naumov, A.S. and Drits, V.A. (1982a) X-ray diffraction by mixed-layer structures with random distribution of stacking faults. Doklady Akademii Nauk SSSR, 265, 339–343 (in Russian).
Sakharov, B.A., Naumov, A.S. and Drits, V.A. (1982b) X-ray intensities scattered by layer structure with short range ordering parameters S ⩾ 1 and G ⩾ 1. Doklady Akademii Nauk SSSR, 265, 871–874 (in Russian).
Sakharov, B.A., Lindgreen, H., Salyn, A.L. and Drits, V.A. (1999) Determination of illite-smectite structures using multispecimen X-ray diffraction profile fitting. Clays and Clay Minerals, 47, 555–566.
Tsipursky, S.J., Eberl, D.D. and Buseck, P.R. (1992) Unusual tops (bottoms?) of particles of 1M illite from the Silverton caldera (CO). Pp. 381–382 in: Proceedings of the American Society of Agronomy annual meeting, Minneapolis, 1992. American Society of Agronomy, Madison, Wisconsin.
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Sakharov, B.A., Plançon, A., Lanson, B. et al. Influence of the Outer Surface Layers of Crystals on the X-Ray Diffraction Intensity of Basal Reflections. Clays Clay Miner. 52, 680–692 (2004). https://doi.org/10.1346/CCMN.2004.0520602
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DOI: https://doi.org/10.1346/CCMN.2004.0520602