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A (1:1) 7-Å Fe Phase and its Transformation in Recent Sediments: An HRTEM and AEM Study

Published online by Cambridge University Press:  28 February 2024

Marc Amouric ,
Claude Parron ,
Lionel Casalini  and
Pierre Giresse
Marc Amouric
Affiliation:
Centre de Recherche sur les Mécanismes de la Croissance Cristalline CRMC2-CNRS, Campus de Luminy, case 913, 13288 Marseille Cedex 9, France
Claude Parron
Affiliation:
Laboratoire de Géosciences de l'Environnement-URA CNRS 132, Université d'Aix-Marseille III, 13397 Marseille Cedex 20, France
Lionel Casalini
Affiliation:
Laboratoire de Géosciences de l'Environnement-URA CNRS 132, Université d'Aix-Marseille III, 13397 Marseille Cedex 20, France
Pierre Giresse
Affiliation:
Laboratoire de Sédimentologie Marine, Université de Perpignan, Av. de Villeneuve, 66025 Perpignan, France
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Abstract

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Young marine green grains, from Fe-rich sediments, were studied by using HRTEM systematically combined with punctual microchemical EDX analyses. Experimental results demonstrated these grains were made of a mixture of very small phases (mainly 1:1 and 2:1 silicates layer phases) with a dominant 7-Å Fe specie. All the main crystallochemically characterized phases appeared intimately related in the same evolutionary process. Each of them experienced different and well described conversion mechanisms. So first, a starting original Fe-rich kaolinite recrystallized via solution into another particular 7-Å Fe-rich phase, the composition of which varies from a di-tri to a pure trioctahedral (Mg + Fe) end member.

This Fe-rich 1:1 mineral is effectively not a classical one. Then crystallization of a 10Å, rather dioctahedral K-rich phase occurs at the expense of it, through 1:½:1 interstratified structures. Such an evolution takes place through a solid state mechanism in which one 10-Å layer replaces one 7-Å layer. Another part of mica-like structures may also directly develop after dissolution of original kaolinites. The development of 10-Å K-rich phases could be significative of the beginning of the glauconitization process in these grains.

Keywords

7-Å Fe phase10-Å phyllosilicatesAEMHRTEMMarine sedimentsPhase transformation
Type
Research Article
Information
Clays and Clay Minerals , Volume 43 , Issue 4 , August 1995 , pp. 446 - 454
Copyright
Copyright © 1995, The Clay Minerals Society

References

Amouric, M., 1987. Growth and deformation defects in phyllosilicates as seen by HRTEM. Acta. Crystallog. B 43: 57–63.Google Scholar
Amouric, M., Gianetto, I., and Proust, D. 1988. 7, 10 and 14Å mixed layer phyllosilicates studied structurally by TEM in pelitic rocks of the Piemontese zone (Venezuela). Bull. Miner. 111: 29–37.Google Scholar
Amouric, M., Mercuriot, G., and Baronnet, A. 1981. On computed and observed HRTEM images of perfect mica polytypes. Bull. Miner. 104: 298–313.Google Scholar
Amouric, M., and Olives, J. 1991. Illitization of smectite as seen by HRTEM. Eur. J. Miner. 3: 831–835.CrossRefGoogle Scholar
Amouric, M., and Parron, C. 1992. About the glauconitization process. An HRTEM and microchemical study. Proc. Mediter. Clay Meet. Lipari 11–12.Google Scholar
Banfield, J. F., and Eggleton, R. A. 1988. Transmission electron microscope study of biotite weathering. Clays & Clay Miner. 36: 47–60.Google Scholar
Casalini, L., Amouric, M., and Parron, C. 1993. Origine et nature d'une phase à 7Å (T.O.) ferrifère: Étude METHR et EDX. Bull. SFMC, vol. 5 n° 3, 58–59.Google Scholar
Cliff, G., and Lorimer, G. W. 1975. The quantitative analysis of thin specimens. J. Microscopy 103: 203–207.CrossRefGoogle Scholar
Giresse, P., 1985. Le fer et les glauconies au large du fleuve Congo. Sci. Geol. Strasbourg 38: 293–322.Google Scholar
Giresse, P., Wiewiora, A., and Lacka, B. 1988. Mineral phases and processes within green peloids from two recent deposits near the Congo river mouth. Clay Miner. 23: 447–458.Google Scholar
Lee, J. H., and Peacor, D. R. 1983. Interlayer transitions in phyllosilicates of Martinsburg shale. Nature 303: 608–609.Google Scholar
Odin, G. S., Amouric, M., Bailey, S. W., and Mackinnon, I. D. R. 1989. Mineralogie du facies verdine. C.R. Acad. Sci. Paris 308: 395–400.Google Scholar
Odin, G. S., Bailey, S. W., Amouric, M., Fröhlich, F., and Waychunas, G. A. 1988. Mineralogy of the facies verdine. In Green Marine Clays. Odin, G. S., ed. Amsterdam: Elsevier, 159–206.Google Scholar
Odin, G. S., and Giresse, P. 1972. Formation des Minéraux phylliteux (berthierine, smectites ferrifères, glauconites ouvertes) dans les sédiments du Golfe de Guinée. C. R. Acad. Sci. Paris 275: 177–189.Google Scholar
Odin, G. S., and Matter, A. 1981. De glauconiarum origine. Sedimentology 28: 611–641.Google Scholar
Olives, J., and Amouric, M. 1984. Biotite chloritization by interlayer brucitization as seen by HRTEM. Am. Miner. 69: 869–871.Google Scholar
Parron, C., 1989. Voies et mécanismes de cristallogénèse des minéraux argileux ferrifères en milieu marin: Ph.D. thesis. Marseille, 189 pp.Google Scholar
Petit, S., and Decarreau, A. 1990. Hydrothermal (200°C) synthesis and crystal chemistry of iron-rich kaolinites. Clay Miner. 25: 181–196.Google Scholar
Porrenga, D. H., 1967. Clay mineralogy and geochemistry of recent marine sediments in tropical areas. Publ. Fysich-Geographishes Lab. Univ., Dort-Stolk, Amsterdam, 155 pp.Google Scholar
Sing, B., and Gilkes, R. J. 1991. Weathering of a chromian muscovite to kaolinite. Clays & Clay Miner. 39: 571–579.Google Scholar
Von Gaertner, H. R., and Schellman, W. 1965. Rezente sediments in Küstenbereich der Halbinsel Kaloun, Guinea. Tscher. Miner. Pet. Mitt. 10: 349–367.Google Scholar