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Microstructure in Mixed-Layer Illite/Smectite and Its Relationship to the Reaction of Smectite to Illite

Published online by Cambridge University Press:  02 April 2024

T. E. Bell
T. E. Bell*
Affiliation:
Utah International Inc., 550 California Street, San Francisco, California 94104
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Abstract

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The reaction of smectite to illite in shale from the COST 1 well in the south Texas Gulf Coast and from altered ash-fall tuffs from the Morrison Formation in New Mexico was investigated using X-ray powder diffraction in conjunction with transmission electron microscopy. In the COST 1 well, the bulk of the detrital clay was originally a K+-deficient mixed-layer illite/smectite (I/S). As the I/S adsorbed K+ released by the dissolution of K-feldspar during burial, the proportion of expandable layers decreased with depth from ~65% near the top of the well to ~25% at 4500 m depth. In contrast, the proportion of low-charged structural planes [<0.8 eq per (Al,Si)4O10 unit] in the I/S decreased gradually from ~40% near the top of the well to ~15% near the bottom. Authigenic smectite with 100% expandable layers from the Morrison Formation tuffs is an alteration product of vitric ash. Where these tuffs have been buried to ~ 1400 m the smectite has reacted to form I/S with ~ 15% expandable layers.

Direct lattice images of I/S crystallites from both locations reveal a correspondence between edge dislocations and the interface between illite layers and smectite layers. Al, Si, Fe, Ca, Mg, and Na were apparently mobile along these dislocations as the reaction of smectite to illite proceeded. Al was probably retained within the crystallite when illite layers replaced the smectite layers; however, some of the remaining cations were expelled. Lateral replacement of smectite layers by illite appears to have been the principal growth mechanism.

Keywords

Edge dislocationUlliteLattice imageMixed layerSmectiteTransmission electron microscopyX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 34 , Issue 2 , April 1986 , pp. 146 - 154
Copyright
Copyright © 1986, The Clay Minerals Society

References

Ahn, J. H. and Peacor, D. R., 1984 The TEM and AEM characterization of chlorite diagenesis in Gulf Coast argillaceous sediments Geol. Soc. Amer., Abstracts with Programs 16 427.Google Scholar
Bell, T. E., Turner-Peterson, C. E. and Santos, E., 1986 Depositional and diagenetic trends in the Brushy Basin and upper Westwater Canyon Members of the Morrison Formation, San Juan basin, New Mexico A Basin Analysis Case Study: Uranium in the Morrison Formation, New Mexico Studies in Geology Amer. Assoc. Petrol. Geol. (in press).Google Scholar
Boles, J. R. and Franks, S. G., 1979 Clay diagenesis in Wilcox sandstones of southwest Texas: implications of smectite diagenesis on sandstone cementation J. Sed. Petrol. 49 55–70.Google Scholar
Burst, J. F. and Swineford, A., 1959 Post-diagenetic clay mineral environmental relationships in the Gulf Coast Eocene Clays and Clay Minerals, Proc. 6th Natl. Conf., Berkeley, California, 1959 New York Pergamon Press 327–341.Google Scholar
Burst, J. F., 1969 Diagenesis of Gulf Coast clayey sediments and its possible relation to petroleum migration Amer. Assoc. Petrol. Geol. Bull. 53 73–79.Google Scholar
Drever, J. I., 1973 The preparation of oriented clay mineral specimens for X-ray diffraction analysis by a filter-membrane peel technique Amer. Mineral. 58 553–554.Google Scholar
Eggleton, R. A. and Buseck, P. R., 1980 High resolution electron microscopy of feldspar weathering Clays & Clay Minerals 28 173–178.CrossRefGoogle Scholar
Howard, J. J., 1981 Lithium and potassium saturation of illite/smectite clays from interlaminated shales and sandstones Clays & Clay Minerals 29 136–142.CrossRefGoogle Scholar
Hower, J., Eslinger, E. V., Hower, M. and Perry, E. A., 1976 Mechanism of burial metamorphism of argillaceous sediment: 1. Mineralogy and chemical evidence Geol. Soc. Amer. Bull. 87 725–737.2.0.CO;2>CrossRefGoogle Scholar
Lagaly, G., 1982 Layer charge heterogeneity in vermiculites Clays & Clay Minerals 30 215–222.CrossRefGoogle Scholar
Lagaly, G., Weiss, A. and Heller, L., 1969 Determination of the layer charge in mica-type layer silicates Proc. Int. Clay Conf., Tokyo, 1969, Vol. 1 Jerusalem Israel Univ. Press 61–80.Google Scholar
Lee, S. Y., Jackson, M. L. and Brown, J. L., 1975 Micaceous occlusion in kaolinite observed by ultramicrotomy and high resolution electron microscopy Clays & Clay Minerals 23 125–129.CrossRefGoogle Scholar
Nadeau, P. H., Tait, J. M., McHardy, W. J. and Wilson, M. J., 1984 Interstratified XRD characteristics of physical mixtures of elementary clay particles Clay Miner. 19 67–76.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984 Interparticle diffraction: a new concept for interstratified clays Clay Miner. 19 757–769.CrossRefGoogle Scholar
Page, R. and Wenk, H. R., 1979 Phyllosilicate alteration of plagioclase studied by transmission electron microscopy Geology 7 393–397.2.0.CO;2>CrossRefGoogle Scholar
Perry, E. A. and Hower, J., 1970 Burial diagenesis in Gulf Coast pelitic sediments Clays & Clay Minerals 18 165–177.CrossRefGoogle Scholar
Reynolds, R. C., 1968 The effect of particle size on apparent lattice spacings Acta Crystallogr. 24 319–320.CrossRefGoogle Scholar
Reynolds, R. C., Brindley, G. W. and Brown, G., 1980 Interstratified clay minerals Crystal Structures of Clay Minerals and Their X-Ray Identification London Mineralogical Society 305–360.Google Scholar
Reynolds, R. C. and Hower, J., 1970 The nature of inter-layering in mixed-layer illite-montmorillonites Clays & Clay Minerals 18 25–36.CrossRefGoogle Scholar
Sawhney, B. L., 1972 Selective sorption and fixation of cations by clay minerals: a review Clays & Clay Minerals 20 93–100.CrossRefGoogle Scholar