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Structural Variations in Chlorite and Illite in a Diagenetic Sequence from the Imperial Valley, California

Published online by Cambridge University Press:  02 April 2024

Jeffrey R. Walker  and
Graham R. Thompson
Jeffrey R. Walker*
Affiliation:
Department of Geology, University of Montana, Missoula, Montana 59812
Graham R. Thompson
Affiliation:
Department of Geology, University of Montana, Missoula, Montana 59812
*
1Present address: Department of Geology and Geography, Vassar College, Poughkeepsie, New York 12601
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Abstract

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Samples of cuttings from the Borchard A-2 well, Imperial Valley, California, were collected over a measured borehole temperature interval 135° to 275°C. The <0.5-µm (e.s.d.) fraction was separated using high-gradient magnetic separation (HGMS) to create a nonmagnetic fraction rich in illite and a magnetic fraction rich in chlorite. Chlorite was less easily separated from illite in lower temperature samples (<200°C), presumably due to the presence of polymineralic grains of chlorite and illite. Grains in higher temperature samples were more nearly monomineralic and more easily separated.

The chlorite is the IIb polytype. The thickness of coherent scattering domains of chlorite increased until 220°C and then remained constant. The amount of 7-Å interstratified material increased downhole until 195°C and then decreased. Over the same temperature interval, the illite polytypes varied systematically from 1Md (135° to 175°C) to 1M + 2M1 (230° to 275°C) and coherent scattering domains in the mineral became thicker to about 200°C and then remained constant in thickness. The percentage of illite in mixed-layer illite/smectite (I/S) increased from 40% at 135°C to 100% at temperature >205°C; ordering in the I/S changes from R0 to R1 between 135° and 155°C, and from R1 to R ≥ 3 at temperatures >155°C.

The concurrent structural changes in chlorite and illite indicate a general improvement in the overall structural order of the clay minerals with increasing temperature. Differences between chlorite and illite suggest that the minerals may have reacted differently to changing conditions or that they may have formed by different mechanisms. The exclusive occurrence of IIb chlorite at temperatures as low as 135°C extends the limit of IIb chlorite stability to temperatures lower than previous estimates.

Keywords

ChloriteDiagenesisHigh-gradient magnetic separationIlliteInterstratificationPolytypeX-ray powder diffraction
Type
Research Article
Information
Clays and Clay Minerals , Volume 38 , Issue 3 , June 1990 , pp. 315 - 321
Copyright
Copyright © 1990, The Clay Minerals Society

References

Ahn, J. H. and Peacor, D. R., 1985 Transmission electron microscopic study of diagenetic chlorite in Gulf Coast argillaceous sediments Clays & Clay Minerals 33 228 – 237.CrossRefGoogle Scholar
Bailey, S. W., Brindley, G. W. and Brown, G., 1984 Structures of layer silicates Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society 2 – 123.Google Scholar
Bailey, S. W. and Brown, B. E., 1963 Chlorite polytypism I. Regular and semirandom one-layer structures Amer. Mineral 47 819 – 850.Google Scholar
Baxter, S. M. and Peacor, D. R., 1988 TEM observations of polytypism in illite Programs and Abstracts Michigan Annual Meeting, The Clay Minerals Society, Grand Rapids 74.Google Scholar
Beskin, E. A., 1984 Compositional variations of authigenic chlorites in the Tuscaloosa Formation, Upper Cretaceous, of the Gulf Coast Basin Programs and Abstracts Baton Rouge, Louisiana Annual Meeting, The Clay Minerals Society 25.Google Scholar
Boles, J. R. and Franks, G. G., 1979 Clay diagenesis in Wilcox sandstones of southwest Texas: Implications of smectite diagenesis on sandstone cementation J. Sed. Petrology 49 55 – 70.Google Scholar
Brindley, G. W., Brindley, G. W. and Brown, G., 1984 Order-disorder in clay mineral structures Crystal Structures of Clay Minerals and Their X-ray Identification London Mineralogical Society 125 – 196.Google Scholar
Drever, J. I., 1973 The preparation of oriented clay mineral specimens for X-ray diffraction analysis by a filter-membrane peel technique Amer. Mineral 50 741 – 751.Google Scholar
Eslinger, E. V. and Savin, S., 1973 Oxygen isotope geothermometry of the burial metamorphic rocks of the Precambrian Belt Supergroup, Glacier National Park, Montana Geol. Soc. Amer. Bull 84 2549 – 2560.2.0.CO;2>CrossRefGoogle Scholar
Hayes, J. B., 1970 Polytypism of chlorite in sedimentary rocks Clays & Clay Minerals 18 285 – 306.CrossRefGoogle Scholar
Hower, J., Eslinger, E. V., Hower, M. E. and Perry, E. A., 1976 Mechanism of burial metamorphism of argillaceous sediments Geol. Soc. Amer. Bull 87 725 – 737.2.0.CO;2>CrossRefGoogle Scholar
Ishii, K., 1988 Grain growth and re-orientation of phyl-losilicate minerals during the development of slaty cleavage in the South Kitakami Mountains, northeast Japan J. Struct. Geol 10 145 – 154.CrossRefGoogle Scholar
Jennings, S. and Thompson, G. R., 1986 Diagenesis of Plio-Pleistocene sediments of the Colorado River delta, southern California J. Sed. Petrol 56 89 – 98.Google Scholar
Karpova, G. V., 1969 Clay mineral post-sedimentary ranks in terrigenous rocks Sedimentology 13 5 – 20.CrossRefGoogle Scholar
Kubler, B., 1964 Les argiles, indicateurs de metamorphisme Rev. Inst. Franc. Petrole 19 1093 – 1112.Google Scholar
Lee, J. H., Ahn, J. H. and Peacor, D. R., 1985 Textures in layered silicates: Progressive changes through diagenesis and low-temperature metamorphism J. Sed. Petrol 55 532 – 540.Google Scholar
Maxwell, D. T. and Hower, J., 1967 High-grade diagenesis and lowgrade metamorphism of illite in the Precambrian Belt Series Amer. Mineral 52 843 – 856.Google Scholar
McDowell, S. D. and Elders, W. A., 1980 Authigenic layer silicate minerals in borehole Elmore 1, Salton Sea Geo-thermal Field, California Contrib. Mineral. Petrology 74 293 – 310.CrossRefGoogle Scholar
Muffler, L. J. and Doe, B. R., 1968 Composition and mean age of detritus of the Colorado River delta in the Salton Trough, southeastern California J. Sed. Petrol 38 384 – 399.Google Scholar
Muffler, L. J. and White, J. P., 1969 Active metamorphism of Upper Cenozoic sediments in the Salton Sea Geothermal Field and the Salton Sea trough, southeastern California Geol. Soc. Amer. Bull 80 157 – 182.CrossRefGoogle Scholar
Nadeau, P. H. and Reynolds, R. C. Jr., 1981 Burial and contact metamorphism in the Mancos Shale Clays & Clay Minerals 29 249 – 259.CrossRefGoogle Scholar
Reynolds, R. C. Jr., 1963 Potassium-rubidium ratios and polymorphism in illites and microclines from the clay size fractions of Proterozoic carbonate rocks Geochim. Cos-mochim. Acta 27 1097 – 1112.CrossRefGoogle Scholar
Reynolds, R. C. Jr., 1985 NEWMOD-A computer program for the calculation of one-dimensional diffraction profiles of clays .Google Scholar
Reynolds, R. C. Jr. and Bailey, S. W., 1988 Mixed layer chlorite minerals Hydrous Phyllosilicates Exclusive of Micas) Washington, D.C. Mineralogical Society of America 601 – 629.CrossRefGoogle Scholar
Reynolds, R. C. Jr. and Hower, J., 1970 The nature of interlayering in mixed-layer illite-montmorillonites Clays & Clay Minerals 18 25 – 36.CrossRefGoogle Scholar
Roedder, E. and Howard, K. W., 1988 Fluid inclusions in Salton Sea Scientific Drilling Project core: Preliminary results J. Geophys. Res 93 13 159 13.CrossRefGoogle Scholar
Sass, J. H., Priest, S. S., Duda, L. E., Carson, C. C., Hendricks, J. D. and Robison, L. C., 1988 Thermal regime of the State 2–14 well, Salton Sea Scientific Drilling Project J. Geophys. Res 93 12 995 13.CrossRefGoogle Scholar
Srodon, J., Eberl, D. and Bailey, S. W., 1984 Illite Micas Washington, D.C. Mineralogical Society of America 495 – 554.CrossRefGoogle Scholar
Tellier, K. E., Hluchy, M. M., Walker, J. R. and Reynolds, R. C. Jr., 1988 Application of high gradient magnetic separation (HGMS) to structural and compositional studies of clay mineral mixtures J. Sed. Petrol 58 761 – 763.CrossRefGoogle Scholar
Thompson, G. R. and McCarty, D., 1988 Burial diagenesis in two non-marine Tertiary basins, southwestern Montana Programs and Abstracts Michigan Annual Meeting, The Clay Minerals Society, Grand Rapids 129.Google Scholar
Velde, B., 1965 Experimental determination of muscovite polymorph stabilities Amer. Mineral 50 436 – 499.Google Scholar
Velde, B., Suzuki, T. and Nicot, E., 1986 Pressure, temperature, and composition of illite/smectite mixed-layer minerals: Niger Delta mudstones and other examples Clays & Clay Minerals 34 435 – 441.CrossRefGoogle Scholar
Walker, J. R., 1987 Structural and compositional aspects of low-grade metamorphic chlorite Hanover, New Hampshire Dartmouth College.CrossRefGoogle Scholar
Walker, J. R., 1989 Polytypism of chlorite in very low-grade metamorphic rocks Amer. Mineral 74 738 – 743.Google Scholar
Whitney, G. and Northrop, H. R., 1988 Experimental investigation of the smectite to illite reaction: Dual reaction mechanisms and oxygenisotope systematics Amer. Mineral 73 77 – 90.Google Scholar
Yau, Y.-C. Peacor, D. R. and Essene, E. J., 1987 Smectite-illite reactions in Salton Sea shales J. Sed. Petrol 57 335 – 342.Google Scholar
Yau, Y.-C. Peacor, D. R., Beane, R. E., Essene, E. J. and McDowell, S. D., 1988 Microstructures, formation mechanisms, and depth-zoning of phyllosilicates in geo-thermally altered shales, Salton Sea, California Clays & Clay Minerals 36 1 – 10.Google Scholar
Yoder, H. S. and Eugster, H. P., 1955 Synthetic and natural muscovites Geochim. Cosmochim. Acta 8 225 – 280.CrossRefGoogle Scholar