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Compositional End Members and Thermodynamic Components of Illite and Dioctahedral Aluminous Smectite Solid Solutions

Published online by Cambridge University Press:  28 February 2024

Barbara Ransom  and
Harold C. Helgeson
Barbara Ransom*
Affiliation:
Department of Geology and Geophysics, University of California, Berkeley, California 94720
Harold C. Helgeson
Affiliation:
Department of Geology and Geophysics, University of California, Berkeley, California 94720
*
1Current address: Geosciences Research Division 0220, Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0220
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Abstract

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Consideration of XRD, TEM, AEM, and analytical data reported in the literature indicates that dioctahedral aluminous smectite and illite form two separate solid solutions that differ chemically from one another primarily by the extent of Al substitution for Si, the amount of interlayer K, and the presence of interlayer H2O. The data indicate that limited dioctahedral-trioctahedral and dioctahedral-vacancy compositional variations occur in both minerals. Excluding interlayer H2O and based on a half unit cell [i.e., O10(OH)2], natural dioctahedral smectite and illite solid solutions fall within the compositional limits represented by A0.3${\rm{R}}_{1.9}^{3 + }$Si4O10(OH)2-AR2+ R3+ Si4O10(OH)2-A0.25${\rm{R}}_{0.3}^{2 + }{\rm{R}}_{1.8}^{3 + }$Al0.25Si3.75O10(OH)2 for smectites and A0.8${\rm{R}}_{1.9}^{3 + }$Al0.5Si3.5O10(OH)2-A0.55${\rm{R}}_{0.45}^{2 + }{\rm{R}}_{1.55}^{3 + }$Al0.1Si3.9O10(OH)2-A0.9${\rm{R}}_{0.3}^{2 + }{\rm{R}}_{1.8}^{3 + }$Al0.9Si3.1O10(OH)2 for illites, where A represents either monovalent cations or divalent cations expressed as their monovalent equivalent (e.g., Ca2+/2); R2+ stands for the divalent cations Mg2+ and Fe2+ and R3+ refers to the trivalent cations Al3+ and Fe3+. Taking account of these compositional limits, smectite and illite solid solutions can be described in terms of nine and six thermodynamic components, respectively, all of which are consistent with both the law of definite proportions and the concept of a unit cell. Thermodynamic components that can be used to describe natural smectite solid solutions in terms of a half unit cell [i.e., O10(OH)2] can be expressed as NaAl3Si3O10(OH)2, NaAl3Si3O10(OH)2 ·4.5H2O, Al2Si4O10(OH)2, Fe2Si4O10(OH)2, Mg3Si4O10(OH)2, Fe3Si4O10(OH)2, K3AlSi4O10(OH)2, KAl3Si3O10(OH)2, and Ca0.5Al3Si3O10(OH)2. Of these, NaAl3Si3O10(OH)2 ·4.5H2O provides explicitly for the presence of interlayer H2O in the mineral. Thermodynamic components representing illite solid solutions in natural systems can be written for a half unit cell as KAl3Si3O10(OH)2, KMg3AlSi3O10(OH)2, KFe3AlSi3O10(OH)2, Al2Si4O10(OH)2, KFe2AlSi3O10(OH)2, and K3AlSi4O10(OH)2. The calculations and observations summarized below indicate that neither smectite nor illite occur in nature as stoichiometric phases and that the two minerals do not form a mutual solid solution corresponding to mixed-layered illite/smectite.

Keywords

Clay mineralsCompositionEnd membersIlliteI/S claysMixed-layered claysSmectiteStoichiometryStructural formulaThermodynamic componentsThermodynamic status
Type
Research Article
Information
Clays and Clay Minerals , Volume 41 , Issue 5 , October 1993 , pp. 537 - 550
Copyright
Copyright © 1993, The Clay Minerals Society

Footnotes

2

2 In accord with the classification system established by the AIPEA (Bailey et al.. 1984), the terms smectite and illite are used in the present communication to refer to two separate mineral groups that have specific crystallographic and chemical characteristics that distinguish the species in one group from those in the other.

References

Aagaard, R. and Helgeson, H. C., 1983 Activity/composition relations among silicates and aqueous solutions: II. Chemical and thermodynamic consequences of ideal mixing of atoms on homological sites in montmorillonites, il-lites, and mixed-layer clays Clays & Clay Minerals 31 207 – 217 10.1346/CCMN.1983.0310306.CrossRefGoogle Scholar
Ahn, J. H. and Peacor, D. R., 1986 Transmission and analytical electron microscopy of the smectite-to-illite transition Clays & Clay Minerals 34 165 – 179 10.1346/CCMN.1986.0340207.Google Scholar
Bailey, S. W., Brindley, G. W., Fanning, D. S., Kodama, H. and Martin, R. T., 1984 Report of The Clay Minerals Society Nomenclature Committee for 1982and 1983 Clays & Clay Minerals 32 239 – 240 10.1346/CCMN.1984.0320316.CrossRefGoogle Scholar
Brigatti, M. F. and Poppi, L., 1981 A mathematical model to distinguish the members of the dioctahedral smectite series Clay Miner. 16 81 – 89 10.1180/claymin.1981.016.1.06.CrossRefGoogle Scholar
Duplay, J., 1984 Analyses chimiques ponctuelles de particules d’argiles. Relations entre variations de compositions dans une population de particles et temperature de formation Sciences Geologique Bull. 37 307 – 317 10.3406/sgeol.1984.1675.CrossRefGoogle Scholar
Earley, J. W., Osthaus, B. B. and Milne, I. H., 1953 Purification and properties of montmorillonite Amer. Mineral. 38 707 – 724.Google Scholar
Eberl, D. D., Srodon, J., Lee, M., Nadeau, P. H. and Northrop, H. R., 1987 Sericite from the Silverton caldera, Colorado: Correlation among structure, composition, origin, and particle thickness Amer. Mineral. 72 914 – 934.Google Scholar
Eslinger, E., Highsmith, P., Albers, D. and De Mayo, B., 1979 Role of iron reduction in the conversion of smectite to illite in bentonites in the disturbed belt, Montana Clays & Clay Minerals 27 327 – 338 10.1346/CCMN.1979.0270503.CrossRefGoogle Scholar
Foster, M. D., 1951 The importance of exchangeable magnesium and cation-exchange capacity in the study of mont-morillonitic clays Amer. Mineral. 36 717 – 730.Google Scholar
Foster, M. D., 1953 Geochemical studies of clay minerals II—Relation between ionic substitution and swelling in montmorillonites Amer. Mineral. 38 994 – 1006.Google Scholar
Foster, M. D., Swineford, A. and Plummer, N., 1954 The relation between “illite,” beidel-lite, and montmorillonite 2nd National Conference on Clays and Clay Minerals Washington, D. C. National Academy of Sciences 386 – 397.Google Scholar
Garrels, R. M., 1984 Montmorillonite/illite stability diagrams Clays & Clay Minerals 32 161 – 166 10.1346/CCMN.1984.0320301.CrossRefGoogle Scholar
Gaudette, H. E., 1965 Illite from Fond du Lac County, Wisconsin Amer. Mineral. 50 411 – 417.Google Scholar
Gaudette, H. E., Eades, J. L. and Grim, R. E., 1966 The nature of illite Clays & Clay Minerals 13 165 – 166.Google Scholar
Grim, R. E. and Guven, N., 1978 Bentonites—Geology, Mineralogy, Properties, and Uses New York Elsevier.Google Scholar
Guven, N. and Bailey, S. W., 1988 Smectites Hydrous Phyllosilicates Exclusive of Micas Washington, D. C. Mineralogical Society of America 497 – 560 10.1515/9781501508998-018.CrossRefGoogle Scholar
Heller-Kallai, L. and Rozenson, I., 1981 The use of Moss-bauer spectroscopy of iron in clay mineralogy Phys. Chem. Minerals 7 223 – 238 10.1007/BF00311893.CrossRefGoogle Scholar
Holdaway, M. J., 1980 Chemical formulae and activity models for biotite, muscovite, and chlorite applicable to pelitic metamorphic rocks Amer. Mineral. 65 711 – 719.Google Scholar
Hower, J., Eslinger, E., Hower, M. E. and Perry, E. A., 1976 Mechanism of burial metamorphism of argillaceous sediment 1. Mineralogical and chemical evidence Geol. Soc. Am. Bull. 87 725 – 737 10.1130/0016-7606(1976)87<725:MOBMOA>2.0.CO;2.2.0.CO;2>CrossRefGoogle Scholar
Hower, J. and Mowatt, T. C., 1966 The mineralogy of illites and mixed-layer illite-montmorillonites Amer. Mineral. 51 825 – 853.Google Scholar
Huff, W. D., Whiteman, J. A. and Curtis, C. D., 1988 Investigation of a K-bentonite by X-ray powder diffraction and analytical transmission electron microscopy Clays & Clay Minerals 36 83 – 93 10.1346/CCMN.1988.0360111.CrossRefGoogle Scholar
Inoue, A., Kohyama, N., Kitagawa, R. and Watanabe, T., 1987 Chemical and morphological evidence for the conversion of smectite to illite Clays & Clay Minerals 35 111 – 120 10.1346/CCMN.1987.0350203.CrossRefGoogle Scholar
Inoue, A. and Utada, M., 1983 Further investigations of a conversion series of dioctahedral mica/smectites in the Shinzan hydrothermal alteration area, northeast Japan Clays & Clay Minerals 31 401 – 412 10.1346/CCMN.1983.0310601.CrossRefGoogle Scholar
Inoue, A., Watanabe, T., Kohyama, N. and Brusewitz, A. M., 1990 Characterization of illitization of smectite in bentonite beds at Kinnekulle, Sweden Clays & Clay Minerals 38 241 – 249 10.1346/CCMN.1990.0380302.CrossRefGoogle Scholar
Ireland, B. J., Curtis, C. D. and Whiteman, J. A., 1983 Compositional variation within some glauconites and illites and implications for their stability and origins Sedimen-tology 30 769 – 786 10.1111/j.1365-3091.1983.tb00710.x.CrossRefGoogle Scholar
Jiang, W. T., Peacor, D. R., Merriman, R. J. and Roberts, B., 1990 Transmission and analytical electron microscopic study of mixed-layer illite/smectite formed as an apparent replacement product of diagenetic illite Clavs & Clay Minerals 38 449 – 468 10.1346/CCMN.1990.0380501.CrossRefGoogle Scholar
Kelley, W. P., 1945 Calculating formulas for fine grained minerals on the basis of chemical analysis Amer. Mineral. 30 1 – 26.Google Scholar
Kerr, P. F., Hamilton, P. K., and Pill, R. J., (1950) Analytical data on reference clay minerals: American Petroleum Institute Project 49, Clay Minerals Standards, Preliminary Report 7, 160 pp.Google Scholar
Lee, J. H., Ahn, J. H. and Peacor, D. R., 1985 Textures in layer silicates. Progressive changes through diagenesis and low temperature metamorphism J. Sed. Petrol. 55 532 – 540.Google Scholar
Lippmann, F., 1977 The solubility products of complex minerals, mixed crystals, and three-layer clay minerals N. Jb. Miner. Abh. 130 243 – 263.Google Scholar
Lippmann, F., (1982) The thermodynamic status of clay minerals: Proc. 7th Int. Clay Conf. 1981. 475–485.Google Scholar
Maniar, P. D. and Cooke, G. A., 1987 Modal analyses of granitoids by quantitative X-ray diffraction Amer. Mineral. 72 433 – 437.Google Scholar
Merino, E. and Ransom, B., 1982 Free energies of formation of illite solid solutions and their compositional dependence Clays & Clay Minerals 30 29 – 39 10.1346/CCMN.1982.0300104.CrossRefGoogle Scholar
Nadeau, P. H. and Bain, D. C., 1986 Compositions of some smectites and diagenetic illitic clays and implications for their origin Clays & Clay Minerals 34 455 – 464 10.1346/CCMN.1986.0340412.CrossRefGoogle Scholar
Nadeau, P. H., Tait, J. M., McHardy, W. J. and Wilson, M. J., 1984a Interstratified XRD characteristics of physical mixtures of elementary clay particles Clay Miner. 19 67 – 76 10.1180/claymin.1984.019.1.07.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984b Interparticle diffraction. A new concept for interstratified clays Clay Miner. 19 757 – 769 10.1180/claymin.1984.019.5.06.CrossRefGoogle Scholar
Nadeau, P. H., Wilson, M. J., McHardy, W. J. and Tait, J. M., 1984c Interstratified clays as fundamental particles Science 225 923 – 925 10.1126/science.225.4665.923.CrossRefGoogle ScholarPubMed
Newman, A C D Brown, G. and Newman, A. C. D., 1987 The chemical constitution of clays Chemistry of Clays and Clay Minerals New York John Wiley & Sons 1 – 128.Google Scholar
Page, R., (1980) Alteration-mineralization history of the Butte Montana ore deposit and transmission electron microscopy of phyllosilicate alteration phases: Ph.D. thesis, University of California, Berkeley, 226 pp.Google Scholar
Pawloski, G. A., 1985 Quantitative determination of mineral content of geological samples by X-ray diffraction Amer. Mineral. 70 663 – 667.Google Scholar
Ransom, B. and Helgeson, H. C., 1989 On the correlation of expandability with mineralogy and layering in mixed-layer clays Clays & Clay Minerals 37 189 – 191 10.1346/CCMN.1989.0370212.CrossRefGoogle Scholar
Ransom, B., and Helgeson, H. C., (1993a) A chemical and thermodynamic model of dioctahedral 2:1 layer clay minerals in diagenetic processes: Dehydration of smectite as a function of temperature and depth in sedimentary basins: Am. J. Sci. (in press).Google Scholar
Ransom, B., and Helgeson, H. C., (1993b) A chemical and thermodynamic model of dioctahedral 2:1 layer clay minerals in diagenetic processes: Regular solution representation of interlayer dehydration in aluminous smectite: Am. J. Sci. (in press).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 249 – 301.CrossRefGoogle Scholar
Ross, C. S. and Hendricks, S. B., 1945 Minerals of the montmorillonite group. Their origin and relation to soils and clays U.S. Geol. Surv. Prof. Pap. 205–B 23 – 79.Google Scholar
Schultz, L. G., 1969 Lithium and potassium absorption, dehydroxylation temperature and structural water content of aluminous smectites Clays & Clay Minerals 19 137 – 150 10.1346/CCMN.1971.0190302.CrossRefGoogle Scholar
Środoń, J., 1980 Precise identification of illite/smectite interstratifications by X-ray powder diffraction Clays & Clay Minerals 28 401 – 411 10.1346/CCMN.1980.0280601.CrossRefGoogle Scholar
Środoń, J., Eberl, D. D. and Bailey, S. W., 1984 Illite Micas Washington, D. C. Mineralogical Society of America 495 – 544 10.1515/9781501508820-016.CrossRefGoogle Scholar
Środoń, J., Morgan, D. J., Eslinger, E. V., Eberl, D. D. and Karlinger, M. R., 1986 Chemistry of illite/smectite and end-member illite Clays & Clay Minerals 34 368 – 378 10.1346/CCMN.1986.0340403.CrossRefGoogle Scholar
Till, R. and Spears, D. A., 1969 The determination of quartz in sedimentary rocks using an X-ray diffraction method Clays & Clay Minerals 17 323 – 327 10.1346/CCMN.1969.0170509.CrossRefGoogle Scholar
Velde, B. and Brusewitz, M., 1986 Compositional variation in component layers in natural illite/smectite Clays & Clay Minerals 34 651 – 657 10.1346/CCMN.1986.0340605.CrossRefGoogle Scholar
Warren, E. A. and Curtis, C. D., 1989 The chemical composition of authigenic illite within two sandstone reservoirs as analyzed by ATEM day Miner. 24 137 – 156.Google Scholar
Warren, E. A. and Ransom, B., 1992 The influence of analytical error upon the interpretation of chemical variations in clay minerals on standard clay diagrams AEM and XRD Clay Miner. 27 193 – 209 10.1180/claymin.1992.027.2.05.CrossRefGoogle Scholar
Weaver, C. E. and Pollard, L. D., 1973 The Chemistry of Clay Minerals New York Elsevier.Google Scholar
Weir, A. H., 1965 Potassium retention in montmorillon-ites Clay Miner. 6 17 – 22 10.1180/claymin.1965.006.1.03.CrossRefGoogle Scholar
Yau, Y., Peacor, D. R. and McDowell, S. D., 1987 Smec-tite-to-illite reactions in Salton Sea shales: A transmission and analytical electron microscopy study J. Sed. Petrol. 57 335 – 342.Google Scholar
Yoder, H. S. and Eugster, H. P., 1955 Synthetic and natural muscovites Geochim. Cosmochim. Acta 8 255 – 280 10.1016/0016-7037(55)90001-6.CrossRefGoogle Scholar