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Preferred Orientation of Phyllosilicates in Gulf Coast Mudstones and Relation to the Smectite-Illite Transition

Published online by Cambridge University Press:  28 February 2024

Nei-Che Ho ,
Donald R. Peacor  and
Ben A. van der Pluijm
Nei-Che Ho
Affiliation:
Department of Geological Sciences, The University of Michigan, 2534 C.C. Little Building, Ann Arbor, Michigan 48109-1063, USA
Donald R. Peacor
Affiliation:
Department of Geological Sciences, The University of Michigan, 2534 C.C. Little Building, Ann Arbor, Michigan 48109-1063, USA
Ben A. van der Pluijm
Affiliation:
Department of Geological Sciences, The University of Michigan, 2534 C.C. Little Building, Ann Arbor, Michigan 48109-1063, USA
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Abstract

Development of preferred orientations of illite-smectite (I-S) has been studied using X-ray diffraction (XRD) texture goniometry to produce pole figures for clay minerals of a suite of 16 mudstone samples from a core from the Gulf Coast. Samples represent a compaction-loading environment in which the smectite-to-illite (S-I) transition occurs. In five shallow, pre-transition samples, there is no significant preferred orientation for smectite-rich I-S. Development of preferred orientation of I-S, although weak, was first detected at depths slightly less than that of the S-I transition. The degree of preferred orientation, which is always bedding-parallel, increases rather abruptly, but continuously, over a narrow interval corresponding to the onset of the S-I transition, then continues to strengthen only slightly with increasing depth. The degree of post-transition preferred orientation is also dependent on lithology, where the preferred orientation is less well-defined for quartz-rich samples.

Previously obtained transmission electron microscope (TEM) data define textures consistent with the change in orientation over many crystallites. The smectite in pre-transition rocks consists largely of anastomosing, “wavy” layers with variable orientation and whose mean orientation is parallel to bedding, but which deviate continuously from that orientation. This results in broad, poorly defined peaks in pole figures. Post-transition illite, by contrast, consists of thin, straight packets, with most individual crystallites being parallel or nearly parallel to bedding. This results in pole figures with sharply defined maxima. By analogy with development of slaty cleavage in response to tectonic stress during metamorphism, the S-I transition is marked by dissolution of smectite and neocrystallization of illite or I-S locally within the continuous “megacrystals” of smectite. The transition is inferred to have some component of mechanical rotation of coherent illite crystals within a pliant matrix of smectite. The data suggest that change in orientation and coalescence of clay packets plays an important role in the formation of the hydraulic seal required for overpressure generation.

Keywords

Gulf CoastPhyllosilicatesPreferred OrientationSmectite-lllite Transition
Type
Research Article
Information
Clays and Clay Minerals , Volume 47 , Issue 4 , August 1999 , pp. 495 - 504
Copyright
Copyright © 1999, The Clay Minerals Society

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References

Ahn, J.H. and Peacor, D.R., 1986 Transmission and analytical electron microscopy of the smectite-to-illite transition Clays and Clay Minerals 34 165–179 10.1346/CCMN.1986.0340207.Google Scholar
Altaner, S.P. and Ylagen, R.F., 1997 Comparison of structural modes of mixed-layer illite/smectite and reaction mechanisms of smectite illitization Clays and Clay Minerals 45 517–533 10.1346/CCMN.1997.0450404.CrossRefGoogle Scholar
Barker, C., 1972 Aquathermal pressure—role of temperature in development of abnormal-pressure zones American Association of Petroleum Geologists Bulletin 56 2068–2071.Google Scholar
Barron, P.F. Slade, P. and Frost, R.L., 1985 Ordering of aluminum in tetrahedral sites in mixed-layer 2:1 phyllos-ilicates by solid-state high resolution NMR Physical Chemistry 89 3880–3885 10.1021/j100264a023.CrossRefGoogle Scholar
Bruce, C.H., 1984 Smectite dehydration—its relation to structural development and hydrocarbon accumulation in northern Gulf of Mexico basin American Association of Petroleum Geologists Bulletin 68 673–683.Google Scholar
Burst, J.F., 1969 Diagenesis of Gulf Coast clayey sediments and its possible relation to petroleum migration American Association of Petroleum Geologists Bulletin 53 73–93.Google Scholar
Chapman, R.E., 1980 Mechanical versus thermal cause of abnormally high pore pressures in shales American Association of Petroleum Geologists Bulletin 64 2179–2183.Google Scholar
Colten-Bradley, V.A., 1987 Role of pressure in smectite dehydration—effects on geopressure and smectite-to-illite transformation American Association of Petroleum Geologists Bulletin 71 1414–1427.Google Scholar
Dong, H. and Peacor, D.R., 1996 TEM observations of coherent stacking relations in smectite, I/S and illite of shales: Evidence for MacEwan crystallites and dominance of 2M, polytypism Clays and Clay Minerals 44 257–275 10.1346/CCMN.1996.0440211.CrossRefGoogle Scholar
Dong, H. Peacor, D.R. and Freed, R.L., 1997 Phase relations among smectite, Rl illite-smectite, and illite American Mineralogist 82 379–391 10.2138/am-1997-3-416.CrossRefGoogle Scholar
Freed, R.L. and Peacor, D.R., 1987 New insights on diagen-esis and I/S reactions in Texas Gulf Coast sediments Clay Minerals 24 667–668.Google Scholar
Freed, R.L. and Peacor, D.R., 1989 Geopressured shale and sealing effect of smectite to illite transition American Association of Petroleum Geologists Bulletin 73 1223–1232.Google Scholar
Freed, R.L. and Peacor, D.R. (1989b) TEM lattice fringe images with Rl ordering of illite/smectite in Gulf Coast pelitic rocks. Geological Society of America Abstracts with Program, 21, A16.Google Scholar
Freed, R.L. and Peacor, D.R., 1992 Diagenesis and the formation of authigenic illite-rich I/S crystals in Gulf Coast shales: TEM study of clay separates Journal of Sedimentary Petrology 62 220–234.Google Scholar
Gretener, P.E., 1979 Pore pressure: Fundamentals, general ramifications, and implications for structure geology (revised) American Association of Petroleum Geologists, Continuing Education Course Note Series 4 .Google Scholar
Guthrie, G.D. Jr. and Veblen, D.R., 1989 High-resolution transmission electron microscopy of mixed-layer illite/ smectite: Computer simulation Clays and Clay Minerals 37 1–11 10.1346/CCMN.1989.0370101.CrossRefGoogle Scholar
Hower, J. Eslinger, E.V. Hower, M.E. and Perry, E.A., 1976 Mechanism of burial metamorphism of argillaceous sediment: Mineralogical and chemical evidence Geological Society of America Bulletin 87 725–737 10.1130/0016-7606(1976)87<725:MOBMOA>2.0.CO;2.2.0.CO;2>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 Clays and Clay Minerals 38 449–468 10.1346/CCMN.1990.0380501.CrossRefGoogle Scholar
Katsube, T.J. and Williamson, M.A., 1994 Effects of diagen-esis on shale nano-pore structure and implications for sealing capacity Clay Minerals 29 451–461 10.1180/claymin.1994.029.4.05.CrossRefGoogle Scholar
Luo, M. Baker, M.R. and LeMone, D.V., 1994 Distribution and generation of the overpressure system, Eastern Delaware Basin, Western Texas and Southern New Mexico American Association of Petroleum Geologists Bulletin 78 1386–1405.Google Scholar
Magara, K., 1975 Reevaluation of montmorillonite dehydration as cause of abnormal pressure and hydrocarbon migration American Association of Petroleum Geologists Bulletin 59 292–302.Google Scholar
Magara, K., 1975 Importance of aquathermal pressuring effect in Gulf Coast American Association of Petroleum Geologists Bulletin 59 2037–2045.Google Scholar
Maxwell, R.T., 1964 Influence of depth, temperature, and geologic age on porosity of quartzose sandstone American Association of Petroleum Geologists Bulletin 48 697–709.Google Scholar
Mello, U.T. and Karner, G.D., 1996 Development of sediment overpressure and its effect on thermal maturation: Application to the Gulf of Mexico Basin American Association of Petroleum Geologists Bulletin 80 1367–1396.Google Scholar
Mello, U.T. Karner, G.D. and Anderson, R.N., 1994 A physical explanation for the positioning of the depth to the top of overpressure in shale-dominated sequences in the Gulf Coast basin, United States Journal of Geophysical Research 99 2775–2789 10.1029/93JB02899.CrossRefGoogle Scholar
Oertel, G., 1985 The relationship of strain and preferred orientation of phyllosilicate grains in rocks—a review Tectonophysics 100 413–447 10.1016/0040-1951(83)90197-X.CrossRefGoogle Scholar
Pendkar, N. and Jordan, R.R. (1993) Diagenesis of siliciclastic reservoir rocks, Baltimore Canyon Trough, Mid-Atlantic continental margin. Geological Society of America Program with Abstracts, 28, A336.Google Scholar
Perry, E. and Hower, J., 1970 Burial diagenesis in Gulf Coast pelitic sediments Clays and Clay Minerals 18 165–177 10.1346/CCMN.1970.0180306.CrossRefGoogle Scholar
Pevear, D.R. Houser, P.J. Robinson, G.A. and Reynolds, R.C., 1997 Disorder in illite: The differences between shales, K-bentonites, and sandstones—the AFM evidence .Google Scholar
Plumley, W.J., 1980 Abnormally high fluid pressure: Survey of some basic principles American Association of Petroleum Geologists Bulletin 64 414–430.Google Scholar
Powers, M.C., 1967 Fluid-release mechanisms in compacting marine mudrock and their importance in oil exploration American Association of Petroleum Geologists Bulletin 51 1240–1254.Google Scholar
Reynolds, R.C. Jr., 1992 X-ray diffraction studies of illite/smectite from rocks, >1 μm randomly oriented powders and >1 μm oriented powder aggregates: The absence of laboratory-induced artifacts Clays and Clay Minerals 40 387–396 10.1346/CCMN.1992.0400403.CrossRefGoogle Scholar
Sharp, J.M. Jr., 1983 Permeability controls on aquathermal pressuring American Association of Petroleum Geologists Bulletin 67 2057–2061.Google Scholar
Sintubin, M., 1994 Clay fabric in relation to the burial history of shales Sedimentology 41 1161–1169 10.1111/j.1365-3091.1994.tb01447.x.CrossRefGoogle Scholar
Srodon, J., 1980 Precise identification of illite/smectite interstratifications by X-ray powder diffraction Clays and Clay Minerals 32 337–349 10.1346/CCMN.1984.0320501.CrossRefGoogle Scholar
van der Pluijm, B.A. Ho, N.-C. and Peacor, D.R., 1994 High-resolution X-ray texture goniometry Journal of Structural Geology 16 1029–1032 10.1016/0191-8141(94)90084-1.CrossRefGoogle Scholar
van der Pluijm, B.A. Ho, N.-C. and Peacor, D.R., 1995 High-resolution X-ray texture goniometry: Reply Journal of Structural Geology 17 925–926 10.1016/0191-8141(95)00020-E.CrossRefGoogle Scholar
van der Pluijm, B.A., Ho, N-C., Merriman, R.J. and Peacor, D.R. (1998) Contradictions of slate formation resolved? Nature, 392, 348.CrossRefGoogle Scholar
Velde, B. Suzuki, T. and Nicor, E., 1986 Pressure-temperature-composition of illite/smectite mixed-layer minerals: Niger Delta mudstones and other examples Clays and Clay Minerals 34 435–441 10.1346/CCMN.1986.0340410.CrossRefGoogle Scholar
Vernik, L. and Liu, X., 1997 Velocity anisotropy in shales: A petrophysical study Geophysics 62 521–532 10.1190/1.1444162.CrossRefGoogle Scholar
Wenk, H.-R. and Wenk, H.R., 1985 Measurement of pole figures Preferred Orientation in Deformed Metals and Rocks: An Introduction to Modern Texture Analysis New York Academic Press 11–47 10.1016/B978-0-12-744020-0.50007-9.CrossRefGoogle Scholar