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Ordering of illite-smectite in Upper Jurassic Claystones from the North Sea

  • H. Lindgreen (a1) and P. L. Hansen (a2)


Upper Jurassic claystones of Kimmeridgian-Volgian(-Ryazanian) age are the main source rocks for oil in the Central Trough, North Sea. Drill cuttings and cores from the depth interval 2368–4548 m, the interval from early-mature to peak oil generation, have been investigated by high-resolution transmission electron microscopy (HRTEM) of ion-milled rock samples, and by HRTEM and powder X-ray diffraction (XRD) of dispersed illite-smectite (I-S) mixed-layers isolated from the <0·2 µm fraction. Ordering parameters were determined by XRD profile simulation. TEM on shadowed particles, combined with XRD evidence, showed that dispersed I-S consists of a mixture of 10–70 Å thick particles, whereas HRTEM showed that intact bulk rock was dominated by 50–200 Å thick particles. Disruption, possibly along smectite planes, of the larger particles in the bulk rock formed the thin particles in dispersed I-S. HRTEM showed 20 and 30 Å periodic enhancement in the contrast of lattice fringes in bulk rock samples as well as in dispersed I-S crystals. These features were interpreted as ordered I-S crystals. Indications of disintegration of larger I-S particles during sample dispersion and of the presence of ordered I-S crystals in the intact bulk rock support the layer transformation mechanism for the conversion of smectite to illite.



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Ahn, J.H. & Peacor, D.R. (1986a) Transmission and analytical electron microscopy of the smectite-to-illite transition. Clays Clay Miner., 34, 165–179.
Ahn, J.H. & Peacor, D.R. (1986b) Transmission electron microscope data for rectorite: Implications for origin and structure of "fundamental particles". Clays Clay Miner., 34, 180–186.
Ahn, J.H. & Peacor, D.R. (1989) Illite/smectite from Gulf Coast shales: A reappraisal of transmission electron microscope images. Clays Clay Miner., 37, 542–546.
Altaner, S.P., Weiss, C.A. & Kirkpatrick, R.J., (1988) Evidence from 29Si nmrfor the structure of mixed-layer illite- smectite day minerals. Nature, 331, 699–702.
Amouric, M., Mercuriot, G. & Baronett, A. (1981) On computed and observed HRTEM images of perfect mica polytypes. Bull. Mineral., 104, 298–313.
Anderson, J.U. (1963) An improved pretreatment for mineralogical analysis of samples containing organic matter. Clays Clay Miner., 10, 380–388.
Bethke, C.M., Vergo, N, & Altaner, S.P. (1986) Pathways of smectite illitization. Clays Clay Miner., 34, 125–135.
Bell, T.E. (1986) Microstructure in mixed-layer illite/smectite and its relationship to the reaction of smectite to illite. Clays Clay Miner., 34, 146–154.
Burst, J.R. (1959) Postdiagenetic clay mineral environmental relationships in the Gulf Coast Eocene. Clays Clay Miner., 6, 327–341.
Buzagh, A. & Szepesi, K. (1955) A colloid-chemical method for the determination of the montmorillonite content in bentonites. Acta Chim. Hung., 5, 287–298.
Cradwick, P.D. & Wilson, M.J. (1978) Calculated X-ray diffraction curves for the interpretation of a three component interstratified system. Clay Miner., 13, 53–65.
Eberl, D.D. (1978) Reaction series for dioctahedral smectites. Clays Clay Miner., 26, 327–340.
Eberl, D.D. (1984) Clay mineral formation and transformation in rocks and soils. Phil. Trans. R. Soc. Lond. A311, 241257.
Eberl, D.D., & Hower, J. (1976) Kinetics of illite formation. Geol. Soc. Amer. Bull., 87, 1326–1330.
Eberl, D.D. & Hower, J. (1977) The hydrothermal transformation of sodium and potassium smectite into mixed-layer clays. Clays Clay Miner., 25, 215–227.
Eberl, D.D. & Środoiń, J. (1988) Ostwald ripening and interparticle-diffraction effects for illite crystals. Am. Miner., 73, 1335–1345.
Eberl, D.D., Srodon, J., Lee, M., Nadeau, P.H. & Northrop, H.R. (1987) Sericite from the Siiverton caldera, Colorado: Correlation among structure, composition, origin, and particle thickness. Am. Miner., 72, 914–834.
Foscolos, A.E., Powell, T.G. & Gunther, T.G. (1976) The use of clay minerals and inorganic and organic geochemical indicators for evaluating the degree of diagenesis and oil generating potential of shales. Geochim. Cosmochim. Acta, 40, 953–966.
Gibbs, R. J. (1967) Quantitative X-ray diffraction analysis using clay mineral standards extracted from the samples to be analysed. Clay Miner., 7, 79–90.
Glasmann, J.R., Larter, S., Briedis, N.A. & Lundegard, P.D. (1989) Shale diagenesis in the Bergen High area. Clays Clay Miner., 37, 97–112.
Guthrie, G.D. & Veblen, D.R. (1989) High-resolution transmission electron microscopy of mixed-layer illite/ smectite: Computer simulations. Clays Clay Miner., 37, 1–11
Hansen, P.L. & Lindgreen, H. (1987) Structural investigations of mixed-layer smectite-illite clay minerals from North Sea oil rocks. Proc. 45th Ann. Meet. Electron Microsc. Soc. Amer., 374375.
Hansen, P.L. & Lindgreen, H. (1989) Mixed-layer illite/smectite diagenesis in Upper Jurassic cJaystones from the North Sea and onshore Denmark. CZfly Mner. 24, 197213.
Holtzapffel, T. & Chamley, H. (1986) Les smectites lattees du domaine Atlantique depuis le Jurassique Superieur: Gisement et signification. Clay Miner., 21, 133–148.
Iijima, S. & Buseck, P.R. (1978) Experimental study of disordered mica structures by high-resolution electron microscopy. Acta Cryst.A34, 709719.
Inoue, A., Kohyama, N., Kitagawa, R. & Watanabe, T. (1987) Chemical and morphological evidence for the conversion of smectite to illite. Clays Clay Miner., 35, 111–120.
Jagodzinski, H. (1949) Eindimensionale Fehlordnung in Kristallen und ihr Einfluss auf die Rontgeninterferenzen. I. Berechnung des Fehlordnungsgrades aus den Rontgenintensitaten. Acta Cryst., 2, 201–209.
Klimentidis, R.D. & MacKinnon, I.D.R. (1986) High-resolution imaging of ordered mixed-layer clays. Clays Clay Miner., 34, 155–164.
Lindgreen, H. (1985) Diagenesis and primary migration in Upper Jurassic claystone source rocks in North Sea. Am. Ass. Pet. Geol. Bull., 69, 525536.
MacEwan, D.M.C. & Wilson, M. J. (1984) Interlayer and intercalation complexes of clay minerals. Pp. 197248 in: Crystal Structures of Clay Minerals and their X-ray Identification. (Brindley, G.W. & Brown, G., editors). Mineralogical Society, London.
Mehra, O.P. & Jackson, M.L. (1958) Iron oxide removal from soils and days by a dithionite-citrate system buffered with sodium carbonate. Clays Clay Miner., 7, 317–327.
Mering, J. & Oberlin, A. (1974) The smectites. Pp. 231-255 in: The Electron Optical Investigation of Clays (Gard, J.A., editor). Mineralogical Society, London.
Millot, G. (1970) Geology of Clays. Springer Verlag, London.
Nadeau, P.H. (1985) The physical dimensions of fundamental day particles. Clay Miner., 20, 499–514.
Nadeau, P.H., Tait, J.M., McHardy, W.J. & Wilson MJ. (1984) Interstratified XRD characteristics of physical mixtures of elementary clay particles. Clay Miner., 19, 67–76
Nadeau, P.H., Wilson, M.J., McHardy, W.J. & Tait, J.M. (1985) The conversion of smectite to illite during diagenesis: evidence from some illitic clays from bentonites and sandstones. Mineral. Mag., 49, 393400.
Perry, E.A. & Hower, J. (1970) Burial diagenesis of Gulf Coast pelitic sediments. Clays Clay Miner., 18, 165177.
Reynolds, R.C. Jr. (1984) Interstratified day minerals. Pp. 249305 in: Crystal Structures of Clay Minerals and their X-ray Identification(Brindley, G.W. & Brown, G., editors). Mineralogical Society, London.
Reynolds, R.C. Jr. & Hower, J. (1970) The nature of interlayering in mixed-layer illite-montmorillonites. Clays Clay Miner., 18, 25–36.
Srodon, J. (1979) Correlation between coal and clay diagenesis in the Carboniferous of the Upper Silesian coal basin. Proc. Int. Clay Conf., Oxford, 251260.
Veblen, D.R. (1983a) Microstructures and mixed-layering in intergrown wonesite, chlorite, talc, biotite, and kaolinite. Am. Miner., 68, 566–580.
Veblen, D.R. (1983b) Exsolution and crystal chemistry of the sodium mica wonesite. Am. Miner., 68, 554–565.
Veblen, D.R., Guthrie, G.D. Jr., Livi, K.J.T. & Reynolds, R.C. Jr. (1990) High-resolution transmission electron microscopy and electron diffraction of mixed-layer illite/smectite: Experimental results. Clays Clay Miner., 38, 1–13.
Wilson, M.J. & Nadeau, P.H. (1985) Interstratified day minerals and weathering processes. Pp. 97118 in: The Chemistry of Weathering(Drever, J.C., editor). NATO ASI Series C, Mathematical and Physical Series 149, Reidel Publ. Co.


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