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Clay crystal-chemical adaptability and transformation mechanisms

  • J. Cuadros (a1)


Chemical and mineralogical transformations of phyllosilicates are among the most important in diagenetic environments in all types of rocks because they can exert a large control on the processes taking place in such environments and/or provide constraints for the conditions in which phyllosilicate transformation occurred. Dissolution-precipitation and solid-state transformation are usually the two mechanisms proposed for such reactions depending on the crystal-chemical and morphological similarities between parent and neoformed phases together with knowledge of the environmental conditions. These two mechanisms, however, may be at both ends of the spectrum of those operating and many transformations may take place through a mixture of the two mechanisms, generating observable elements that are characteristic of one or the other. In the present literature, the boundaries between the two mechanisms are not clear, mainly because dissolution-precipitation is sometimes defined at nearly atomic scale. It is proposed here that such small-scale processes are considered as a solid-state transformation, and that dissolution-precipitation requires dissolution of entire mineral particles and their dissolved species to pass into the bulk of the solution. Understanding the reaction mechanisms of diagenetic transformations is an important issue because they impinge on geochemical conditions and variables such as cation mobility, rock volume, fabric changes, rock permeability, stable isotope signature and phyllosilicate crystal-chemistry.

I propose that, in the lower range temperatures at which clay mineral transformations take place, energy considerations favour solid-state transformation, or reactions that involve the breaking of a limited number of bonds, over dissolution of entire grains and precipitation of crystals of the new phase. Large morphological changes are frequently invoked as evidence for a dissolution-precipitation mechanism but changes in particle shape and size may be achieved by particle rupture, particle welding or by hybrid processes in which dissolution-precipitation plays a minor role.

Past and recent studies of phyllosilicate transformations show chemical and structural intermediates indicating a large crystal-chemical versatility, greater than is commonly recognized. These intermediates include tetrahedral sheets of different composition within TOT units (termed polar layers), dioctahedral and trioctahedral domains in the same layer, and 2:1 and 1:1 domains also within the same layers. The existence of such intermediate structures suggests that the reaction mechanisms that generated them are within the realm of the solid-state transformation processes.

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Copyright © The Mineralogical Society of Great Britain and Ireland 2012 This is an Open Access article, distributed under the terms of the Creative Commons Attribution license. (, which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Ahn, J. H. & Peacor, D. R. (1986) Transmission and analytical electron microscopy of the smectite-toillite transition. Clays and Clay Minerals, 34, 165–179.
Ahn, J. H. & Peacor, D. R. (1987) Kaolinitization of biotite: TEM data and implications for an alteration mechanism. American Mineralogist, 72, 353–356.
Aldega, L., Cuadros, J., Laurora, A. & Rossi, A. (2009) Weathering of phlogopite to beidellite in a karstic environment. American Journal of Science, 309, 689–710.
Alt, J. C. & Jiang, W-T. (1991) Hydrothermally precipitated mixed-layer illite-smectite in recent massive sulfide deposits from the sea floor. Geology, 19, 570–573.
Altaner, S.P. (1986) Comparison of rates of smectite illitization with rates of K-feldspar dissolution. Clays and Clay Minerals, 34, 608–611.
Altaner, S. & Ylagan, R. (1997) Comparison of structural models of mixed-layer illite/smectite and reaction mechanisms of smectite illitization. Clays and Clay Minerals, 45, 517–533.
Amouric, M. & Olives, J. (1998) Transformation mechanisms and interstratification in conversion of smectite to kaolinite: an HRTEM study. Clays and Clay Minerals, 46, 521–527.
Amouric, M., Parron, C., Casalini, L. & Giresse, P. (1995) A (1:1) 7-Å phase and its transformation in recent sediments: an HRTEM and AEM study. Clays and Clay Minerals, 43, 446–454.
Aoudjit, H., Robert, M., Elsass, F. & Curmi, P. (1995) Detailed study of smectite genesis in granitic saprolites by analytical electron microscopy. Clay Minerals, 30, 135–147.
Aspandiar, M. & Eggleton, R. (2002) Weathering of chlorite: I. Reactions and products in microsystems controlled by the primary mineral. Clays and Clay Minerals, 50, 685–698.
Bailey, S.W. (1980) Structures of layer silicates. Pp. 1–124 in: Crystal Structures of Clay Minerals and their X-Ray Identification (Brindley, G.W., editor). Mineralogical Society Monograph no. 5, London.
Banfield, J. & Murakami, T. (1998) Atomic-resolution transmission electron microscopy evidence for the mechanism by which chlorite weathers to 1:1 semiregular chlorite-vermiculite. American Mineralogist, 83, 348–357.
Beaufort, D., Cassangnabere, A., Petit, S., Lanson, B., Berger, G., Lacharpagne, J. C. & Johansen, H. (1998) Kaolinite to dickite reaction in sandstone reservoirs. Clay Minerals, 33, 297–316.
Berkgaut, V., Singer, A. & Stahr, K. (1994) Palagonite reconsidered: paracrystalline illite-smectites from regoliths on basic pyroclastics. Clays and Clay Minerals, 42, 582–92.
Besson, G., Glaesser, R. & Tchoubar, C. (1983) Le cesium, revelateur de structure des smectites. Clay Minerals, 18, 11–19.
Brindley, W., Suzuki, T. & Thiry, M. (1983) Interstratified kaolinite/smectites from the Paris Basin; correlations of layer proportions, chemical compositions and other data. Bulleting de Mineralogie, 106, 403410.
Brindley, G.W., Kao, C.-C., Harrison, J.L., Lipsicas, M. & Raythatha, R. (1986) Relation between structural disorder and other characteristics of kaolinites and dickites. Clays and Clay Minerals, 34, 239–249.
Clauer, N. & Chauduri, S. (1996) Inter-basinal comparison of the diagenetic evolution of illite/smectite minerals in buried shales on the basis of K-Ar systematics. Clays and Clay Minerals, 44, 818–824.
Craw, D., Coombs, D. S. & Kawachi, Y. (1982) Interlayered biotite-kaoline and other altered biotites, and their relevance to the biotite isograd in eastern Otago, New Zealand. Mineralogical Magazine, 45, 79–85.
Cuadros, J. (2010) Crystal-chemistry of mixed-layer clays. Pp. 11–33 in: Interstratified Clay Minerals: Origin, Characterization and Geochemical Significance (S. Fiore, J. Cuadros & F.J. Huertas, editors). AIPEA Educational Series No. 1, Digilabs, Bari, Italy.
Cuadros, J. & Altaner, S. P. (1998) Characterization of mixed-layer illite-smectite from bentonites using microscopic, chemical, and X-ray methods: Constraints on the smectite-to-illite transformation mechanism. American Mineralogist, 83, 762–774.
Cuadros, J. & Dudek, T. (2006) FTIR investigation of the evolution of the octahedral sheet of kaolinitesmectite with progressive kaolinization. Clays and Clay Minerals, 54, 1–11.
Cuadros, J., Nieto, F. & Wing-Dudek, T. (2009) Crystalchemical changes of kaolinite-smectite mixed-layer with progressive kaolinization, as investigated by TEM-AEM and HRTEM. Clays and Clay Minerals, 57, 742–750.
De Bona, J., Dani, N., Ketzer, J. M. & De Ros, L.F. (2008) Dickite in shallow oil reservoirs from Recôncavo Basin, Brazil: diagenetic implications for basin evolution. Clay Minerals, 43, 213–233.
de la Fuente, S., Cuadros, J., Fiore, S. & Linares, J. (2000) Electron microscopy study of volcanic tuff alteration to illite-smectite under hydrothermal conditions. Clays and Clay Minerals, 48, 339–350.
de la Fuente, S., Cuadros, J. & Linares, J. (2002) Early stages of volcanic tuff alteration in hydrothermal experiments: Formation of mixed-layer illite-smectite. Clays and Clay Minerals, 50, 578–590.
Dekov, V.M., Cuadros, J., Shanks, W. C. & Koski, R. A. (2008) Deposition of talc–kerolite-smectite–smectite at seafloor hydrothermal vent fields: Evidence from mineralogical, geochemical and oxygen isotope studies. Chemical Geology, 247, 171–194.
Deocampo, D.M., Cuadros, J., Wing-Dudek, T., Olives, J. & Amouric, M. (2009) Saline lake diagenesis as revealed by coupled mineralogy and geochemistry of multiple ultrafine clay phases: Pliocene Olduvai gorge, Tanzania. American Journal of Science, 309, 834–868.
Drits, V., Salyn, A. & Sucha, V. (1996) Structural transformations of interstratified illite-smectites from Dolná Ves hydrothermal deposits: dynamics and mechanisms. Clays and Clay Minerals, 44, 181–190.
Drits, V., Sakharov, B., Lindgreen, H. & Salyn, A. (1997) Sequential structure transformation of illite-smectitevermiculite during diagenesis of Upper Jurassic shales from the North Sea and Denmark. Clay Minerals, 32, 351–371.
Dudek, T., Cuadros, J. & Fiore, S. (2006) Interstratified kaolinite-smectite: Nature of the layers and mechanism of smectite kaolinization. American Mineralogist, 91, 159–170.
Dudek, T., Cuadros, J. & Huertas, J. (2007) Structure of mixed-layer kaolinite-smectite and smectite-to-kaolinite transformation mechanism from synthesis experiments. American Mineralogist, 92, 179–192.
Eberl, D.D., Środoń, J. & Northrop, H. R. (1986) Potassium fixation in smectite by wetting and drying. Pp. 296–326 in: Geochemical Processes at Mineral Surfaces (J.A. Davis & K.F. Hayes, editors). American Chemical Society Symposiums Series 323, Washington.
Ehrenberg, S., Aagaard, P., Wilson, M.J., Fraser, A. R. & Duthie, D. M.L. (1993) Depth-dependent transformation of kaolinite to dickite in sandstones of the Norwegian continental shelf. Clay Minerals, 28, 325–352.
Ferrage, E., Vidal, O., Mosser-Ruck, R., Cathelineau, M. & Cuadros, J. (2011) A reinvestigation of smectite illitization in experimental hydrothermal conditions: Results from X-ray diffraction and transmission electron microscopy. American Mineralogist, 96, 207–223.
Grauby, O., Petit, S., Decarreau, A. & Baronnet, A. (1993) The beidellite-saponite series: an experimental approach. European Journal of Mineralogy, 5, 625–635.
Güven, N. (1974) Lath-shaped units in fine-grained micas and smectites. Clays and Clay Minerals, 22, 385–390.
Güven, N. (1988) Smectites. Reviews in Mineralogy, 19, 497–560.
Güven, N. (1991) On a definition of illite/smectite mixed-layer. Clays and Clay Minerals, 39, 661–662.
Güven, N. & Huang, W.-L. (1991) Effects of octahedral Mg2+ and Fe3+ substitutions on hydrothermal illitization reactions. Clays and Clay Minerals, 39, 387–399.
Hlavay, J., Jonas, K., Elek, S. & Inczedy, J. (1978) Characterization of the particle size and the crystallinity of certain minerals by IR spectrophotometry and other instrumental methods – II. Investigations on quartz and feldspar. Clays and Clay Minerals, 26, 139–143.
Houben, G. & Kaufhold, S. (2011) Multi-method characterization of the ferrihydrite to goethite transformation. Clay Minerals, 46, 387–395.
Huertas, F.J., Cuadros, J., Huertas, F. & Linares, J. (2000) Experimental study of the hydrothermal formation of smectite in the beidellite-saponite series. American Journal of Science, 300, 504–527.
Huggett, J. M. & Cuadros, J. (2010) Glauconite formation in lacustrine/palaeosol sediments, Isle of Wight (Hampshire basin), UK. Clay Minerals, 45, 35–49.
Hughes, R., Moore, D. & Reynolds, R. (1993) The nature, detection, occurrence, and origin of kaolinite-smectite. Pp. 291–323 in: Kaolin Genesis and Utilization (H.H. Murray, W.M. Bundy & C.C. Harvey editors). Clay Minerals Society Special Publication n. 1, Boulder, USA.
Inoue, A. & Kitagawa, R. (1994) Morphological characteristics of illitic clay minerals from a hydrothermal system. American Mineralogist, 79, 700–711.
Kameda, J., Yamagishi, A. & Kogure, T. (2005) Morphological characteristics of ordered kaolinite: Investigation using electron back-scattered diffraction. American Mineralogist, 90, 1462–1465.
Kogure, T., Elzea-Kogel, J., Johnston, C. T. & Bish, D. L. (2010) Stacking order in a sedimentary kaolinite. Clays and Clay Minerals, 58, 62–71.
Kuwahara, Y., Uehara, S. & Aoki, Y. (1998) Surface microtopography of lath-shaped hydrothermal illite by tapping-mode and contact-mode AFM. Clays and Clay Minerals, 46, 574–582.
Lagaly, G. (1979) The layer charge of regular interstratified 2:1 clay minerals. Clays and Clay Minerals, 27, 1–10.
Laird, D.A. (1990) Layer charge influences on the hydration of expandable 2:1 phyllosilicates. Clays and Clay Minerals, 47, 630–636.
Lanson, B. & Champion, D. (1991) The I/S-to-illite reaction in the late stage diagenesis. American Journal of Science, 291, 473–506.
Lasaga, A.C. (1998) Kinetic Theory in the Earth Sciences. Princeton University Press, Princeton, New Jersey, 811 pp.
Laverret, E., Mas, P., Beaufort, D., Kister, P., Quirt, D., Bruneton, P. & Clauer, N. (2006) Mineralogy and geochemistry of the host-rock alterations associated with the Shea Creek unconformity-type uranium deposits (Athabasca basin, Saskatchewan, Canada). Part 1. Spatial variation of illite properties. Clays and Clay Minerals 54, 275–294.
Lee, J. H. & Peacor, D. R. (1985) Ordered 1:1 interstratification of illite and chlorite: A transmission and analytical electron microscopy study. Clays and Clay Minerals, 33, 463–467.
Li, G., Peacor, D. R. & Coombs, D. S. (1997) Transformation of smectite to illite in bentonite and associated sediments from Kaka Point, New Zealand: Contrast in rate and mechanism. Clays and Clay Minerals, 45, 54–67.
Lynch, F., Mack, L. & Land, L. (1997) Burial diagenesis of illite/smectite in shales and the origins of authigenic quartz and secondary porosity in sandstones. Geochimica et Cosmochimica Acta, 61, 1995–2006.
Ma, C. & Eggleton, R. (1999) Surface layer types of kaolinite: a high-resolution transmission electron microscope study. Clays and Clay Minerals, 47, 181–191.
Nadeau, P.H., Wilson, M.J., McHardy, W. J. & Tait, J. M. (1985) The conversion of smectite to illite during diagenesis: evidence from illitic clays from bentonites and sandstones. Mineralogical Magazine, 49, 393–400.
Newman, A.C.D. (1987) The interaction of water with clay mineral surfaces. Pp. 237–274 in: Chemistry of Clays and Clay Minerals (A.C.D. Newman, editor). Mineralogical Society Monograph no. 6. Longman Scientific and Technical, London.
Proust, D., Caillaud, J. & Fontaine, C. (2006) Clay minerals in early amphibole weathering: tri- to dioctahedral sequence as a function of crystallization sites in the amphibole. Clays and Clay Minerals, 54, 351–362.
Rogen, B. & Fabricius, I. L. (2002) Influence of clay and silica on permeability and capillary entry pressure of chalk reservoirs in the North Sea. Petroleum Geoscience, 8, 287–293.
Ryan, P. C. & Huertas, F. J. (2009) The temporal evolution of pedogenic Fe-smectite to Fe-kaolin via interstratified kaolin-smectite in a moist tropical soil chronosequence. Geoderma, 151, 1–15.
Setti, M., Marinoni, L. & Veniale, F. (2005) Transformation mechanism of lamellar to lathshaped illite/smectite: observation by SEM. Periodico di Mineralogia, 74, 1–10.
Shau, Y. & Peacor, D. (1992) Phyllosilicates in hydrothermally altered basalts from DSDP Hole 504B, Leg 83 – a TEM and AEM study. Contributions to Mineralogy and Petrology, 112, 119–133.
Shutov, V.D., Aleksandrova, A. V. & Losievskaya, S. A. (1970) Genetic interpretation of the polymorphism of the kaolinite group in sedimentary rocks. Sedimentology, 15, 53–68.
Small, J.S., Hamilton, D. L. & Habesch, S. (1992) Experimental simulation of clay precipitation within reservoir sandstones 2: Mechanism of illite formation and controls on morphology. Journal of Sedimentary Petrology, 62, 520–529.
Sondi, I. & Pravdić, V. (1998) The colloid and surface chemistry of clays in natural waters. Croatica Chemica Acta, 71, 1061–1074.
Šucha, V., Elssas, F., Eberl, D., Kuchta, L., Madejová, J., Gates, W. & Komadel, P. (1998) Hydrothermal synthesis of ammonium illite. American Mineralogist, 83, 58–67.
Veniale, F., Delgado, A., Marinoni, L. & Setti, M. (2002) Dickite genesis in the ‘varicoloured’ clay-shale formation of the Italian Apennines: an isotopic approach. Clay Minerals, 37, 255–266.
Wang, Y. & Xu, H. (2006) Geochemical chaos: Periodic and nonperiodic growth of mixed-layer phyllosilicates. Geochimica et Cosmochimica Acta, 70, 1995–2005.
Wilson, M.J. (1966) The weathering of biotite in some Aberdeenshire soils. Mineralogical Magazine, 35, 1080–1093.
Worden, R. & Burley, S. D. (2003) Sandstone diagenesis: the evolution of sand to stone. Pp. 3–44 in: Sandstone Diagenesis – Recent and Ancient (Reprint series volume 4 of the International Association of Sedimentologists) (Burley, S.D. & Worden, R.H., editors). Blackwell, Oxford.
Worden, R. & Morad, S. (2003) Clay minerals in sandstones: controls on formation, distribution and evolution. International Association of Sedimentologists Special Publication, 34, 3–41.
Ylagan, R., Altaner, S. & Pozzuoli, A. (2000) Reaction mechanisms of smectite illitization associated with hydrothermal alteration from Ponza Island, Italy. Clays and Clay Minerals, 48, 610–631.
Zhao, G., Peacor, D. & McDowell, S. (1999) Retrograde diagenesis of clay minerals in the Precambrian Freda sandstone, Wisconsin. Clays and Clay Minerals, 47, 119–130.


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Clay crystal-chemical adaptability and transformation mechanisms

  • J. Cuadros (a1)


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