Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-21T17:52:11.195Z Has data issue: false hasContentIssue false
  • English
  • Français

Some Evidence Supporting the Existence of Polar Layers in Mixed-Layer Illite/Smectite

Published online by Cambridge University Press:  28 February 2024

J. Cuadros  and
J. Linares
J. Cuadros*
Affiliation:
Departamento de Ciencias de la Tierra y Química Ambiental, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008, Granada, Spain
J. Linares
Affiliation:
Departamento de Ciencias de la Tierra y Química Ambiental, Estación Experimental del Zaidín (CSIC), Profesor Albareda 1, 18008, Granada, Spain
*
*Present address: Department of Geology, University of Illinois, 245 Natural History Building, 1301 West Green Street, Urbana, Illinois 61801, USA.
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

The fraction <20 μm of a bentonitic material was selected to study the transformation of smectite into illite under hydrothermal conditions. Powder XRD showed that the studied material was composed of 97% dioctahedral smectite and 3% of quartz, cristobalite and plagioclase. The XRD analysis of the oriented, glycolated sample showed that the smectitic phase was actually a randomly interstratified illite/smectite with 11% illite. The chemical analysis of the sample yielded the structural formula: K0.25Na0.25Ca0.12Mg0.13(Al2.76Fe0.33Mg1.03)(Si7.66Al0.34)O20(OH)4. The reaction conditions of the hydrothermal experiments were: KCl concentrations 0.025, 0.05, 0.1, 0.3, 0.5, 1 M; temperature 60, 120, 175, 200°C; run time 1, 5, 15, 30, 90, 180 days; solid: solution ratio 1:5. XRD of run products showed an important transformation of smectite into illite, in contrast with all other techniques (DTA, IR, NMR), which did not detect any transformation of the original material. This suggests that illite quantification in I/S by means of XRD patterns after hydrothermal experiences can be much affected by other variables. The original material and the run products were analysed by means of DTA. The starting material displayed two dehydroxylation peaks, one at 560°C corresponding to illite, and the other at 650°C corresponding to smectite. Quantification of the two dehydroxylation peaks also yielded a content of 11% illite. The run products displayed DTA diagrams in which the smectitic peak remained unaltered, but the illitic one was reduced or eliminated by the presence of exchangeable K in the interlayer. When exchangeable K was removed the illitic dehydroxylation peak appeared again. The coherence of XRD and DTA in quantifying the proportion of illite layers and the effect of exchangeable K on dehydroxylation of illite layers in mixed-layer illite/smectite seem to be positive proofs of the existence of polar layers.

Keywords

Differential Thermal AnalysisMixed-layer illite/smectitePolar layer
Type
Research Article
Information
Clays and Clay Minerals , Volume 43 , Issue 4 , August 1995 , pp. 467 - 473
Copyright
Copyright © 1995, The Clay Minerals Society

References

Brown, G., 1984. Crystal structures of clay minerals and related phyllosilicates. Phil. Trans. Royal Soc. Lond. A 311: 221–240.Google Scholar
Caballero, E., Porto, M. Fernandes, Linares, J., Huertas, F., and Reyes, E. 1983. Las bentonitas de la Serrata de Níjar (Almería): mineralogía, geoquímica y nineralogénesis [The bentonites from Serrata de Níjar (Almería). Mineralogy, geochemistry and mineralogenesis]. Estudios Geológicos. 39: 121–140.Google Scholar
Dainyak, L. G., Drits, V. A., and Heifits, L. M. 1992. Computer simulation of cation distribution in dioctahedral 2: 1 layer silicates using IR-data: Application to Mössbauer spectroscopy of a glauconite sample. Clays & Clay Miner. 40: 470–479.Google Scholar
Eberl, D. D., Velde, B., and McCormick, T. 1993. Synthesis of illite-smectite from smectite at earth surface temperatures and high pH. Clay Miner. 28: 49–60.Google Scholar
Grauby, O., Petit, S., Decarreau, A., and Baronnet, A. 1993. The beidellite-saponite series: An experimental approach. Eur. J. Mineral. 5: 623–635.Google Scholar
Grauby, O., Petit, S., Decarreau, A., and Baronnet, A. 1994. The nontronite-saponite series: An experimental approach. Eur. J. Mineral. 6: 99–112.Google Scholar
Güven, N., 1991a. On a definition of illite/smectite mixedlayer. Clays & Clay Miner. 39: 661–662.Google Scholar
Güven, N., 1991b. Smectites. In Reviews in Mineralogy, Vol. 19. Bailey, S. W., ed. Washington, D.C.: Mineralogical Society of America, 497–560.Google Scholar
Jiang, W., Peacor, D. R., Merriman, R. J., and Roberts, B. 1990. Transmission and analytical microscopy study of mixed-layer illite/smectite formed as an apparent replacement product of diagenetic illite. Clays & Clay Miner. 38: 449–468.Google Scholar
Kloprogge, J. T., Jansen, J. B., and Geus, J. W. 1990. Characterization of synthetic Na-beidellite. Clays & Clay Miner. 38: 409–414.Google Scholar
Koster van Groos, A. F., and Guggenheim, S. 1987. High-pressure differential thermal analysis (HP-DTA) of the dehydroxylation of Na-rich montmorillonite and K-exchanged montmorillonite. Amer. Mineral. 72: 1170–1175.Google Scholar
Koster van Groos, A. F., and Guggenheim, S. 1989. Dehydroxylation of Ca- and Mg-exchanged montmorillonite. Amer. Mineral. 74: 627–636.Google Scholar
Lanson, B., and Velde, B. 1992. Decomposition of X-Ray diffraction patterns: A convenient way to describe complex I/S diagenetic evolution. Clays & Clay Miner. 40: 629–643.Google Scholar
Mackenzie, R. C., 1970. Simple phyllosilicates based on gibbsite- and brucite-like sheets. In Differential Thermal Analysis, Vol. I. Mackenzie, R. C., ed. London-New York: Academic Press, 498–538.Google Scholar
Marshall, C., 1949. The structural interpretation of chemical analyses of the clay minerals. In The Colloid Chemistry of the Silicate Minerals. New York: Academic Press, 56–55.Google Scholar
Newman, A. C. D., and Brown, G. 1987. The chemical constitution of clays. In Chemistry of Clays and Clay Minerals. Newman, A. C. D., ed. London: Mineralogical Society, 1–129.Google Scholar
Ross, M., 1968. X-ray diffraction effects by non-ideal crystals of biotite, muscovite, montmorillonite, mixed-layer clays, graphite, and periclase. Zeitschrift für Kristallographie 126: 80–97.Google Scholar
Schultz, L. G., 1969. Lithium and potassium absorption, dehydroxylation temperature, and structural water content of aluminous smectites. Clays & Clay Miner. 17: 115–149.Google Scholar
SCIFAX DTA Data Index. 1962. Compiled by R. Mackenzie, C. London: Cleaver-Hume Press.Google Scholar
Soil Conservation Service 1972. Soil Survey Laboratory Methods and Procedure for Collecting Soil Samples. U.S.D.A. Washington, D.F. Method 5A6.Google Scholar
Sudo, T., Hayasi, H., and Shimoda, S. 1962. Mineralogical problems of intermediate clay minerals. Proceedings of the 9th National Conference. 378–390.Google Scholar
Velde, B., 1985. Clay mineral names and structure. In Clay Minerals: A Physico-chemical Explanation of their Occurrence. Velde, B., ed. New York: Elsevier, 7–17.Google Scholar