Effects of Freezing on Colloidal Halloysite: Implications for Temperate Soils
Tóm tắt
The literature reports that freezing of aqueous aluminosilicate clay suspensions can produce clay aggregates that disperse with agitation. Our experiments indicate that colloidal suspensions extracted from north Idaho loess soils (Boralfs), when frozen, form silt- and sand-sized agglomerates that resist dispersion with agitation. XRD and TEM analyses showed that colloids are dominantly halloysite between 0.10 to 0.30 μm in diameter. The colloidal halloysite has anomalously high mole ratios of Si/Al and a high Fe content. Freeze-produced agglomerates are light yellow to yellowish-brown in color, occur in the form of plates, wedges, cuspates, or laths, and often exhibit uniform optical properties, suggesting a crystalline product. Selected area electron diffraction, however, indicates that the agglomerates are polycrystalline. With proper orientation, agglomerates produce acute bisectrix interference figures that are optically negative with variable 2V, generally μ30°. XRD analyses and IR spectra imply that the agglomerates are halloysite. Measured optical properties, however, are difFerent than those reported for halloysite and may be affected by the high Fe content and polycrystalline nature of the agglomerates. Grains, exhibiting similar optical properties as laboratory-produced agglomerates, are a minor proportion of the very-fine sand fraction in some horizons of the soils studied. Freeze-aided agglomeration of colloidal material may be an important process in temperate climates. It may be overlooked because of particle destruction by soil pretreatments or morphological order and/or optical similarity to some micaceous minerals.
Tài liệu tham khảo
Ahlrichs, J. L. and White, J. L. (1962) Freezing and lyophilizing alters the structure of bentonite gels: Science 136, 1116–1118.
Buckley, D. E. and Cranston, R. R. (1970) Atomic absorption analyses of 18 elements from a single decomposition of an aluminosilicate: Chem. Geol. 7, 273–284.
Busacca, A. J. (1989) Long Quaternary record in eastern Washington, U.S.A., interpreted from multiple buried paleosols in loess: Geoderma 45, 105–122.
Corte, A. E. (1962) Vertical migration of particles in front of a moving freezing plane: J. Geophys. Res. 67, 1085–1090.
Deer, W. A., Howie, R. A., and Zussman, J. (1962) Rockforming Minerals. Vol. 3, Sheet Silicates: Longmans, Green and Co. Ltd., London.
Dixon, J. B. (1989) Kaolin and serpentine group minerals: in Minerals in Soil Environments, 2nd ed., J. B. Dixon and S. B. Weed, eds., Soil Sci. Soc. Amer., Madison, Wisconsin, 467–526.
Farmer, V. C. (1974) The layer silicates: in The Infrared Spectra of Minerals, V. C. Farmer, ed., Mineralogical Society, London, 331–363.
Fitzpatrick, E. A. (1984) Micromorphology of Soils: Chapman and Hall, London.
Henmi, T. and Wada, K. (1976) Morphology and composition of allophane: Am. Mineral. 61, 379–390.
Jackson, M. L. (1956) Soil Chemical Analysis—Advanced Course: published by the author, Dept. of Soils, Univ. of Wisconsin, Madison.
Jefferson, D. A., Tricker, M. J., and Winterbottom, A. P. (1975) Electron-microscopic and Mössbauer spectroscopic studies of iron-stained kaolinite minerals. Clays & Clay Minerals 23, 355–360.
Jepson, W. B. and Rowse, J. B. (1975) The composition of kaolinite—An electron microscope microprobe study. Clays & Clay Minerals 23, 310–317.
Kerr, P. F. (1977) Optical Mineralogy: McGraw-Hill, Inc., New York.
Kunze, G. W. and Bradley, W. F. (1964) Occurrence of a tabular halloysite in a Texas soil: Clays & Clay Minerals 12, 523–527.
Langston, R. B. and Pask, J. A. (1969) The nature of anauxite: Clays & Clay Minerals 16, 425–436.
Lincoln, J. and Tettenhorst, R. (1971) Freeze-dried and thawed clay: Clays & Clay Minerals 19, 103–107.
Mubarek, A. and Olsen, R. A. (1976) An improved technique for measuring soil pH: Soil Sci. Soc. Am. J. 40, 880–882.
Newman, A. C. D. and Brown, G. (1987) The chemical constitution of clays: in Chemistry of Clays and Clay Minerals, Mineralogical Society Monograph No. 6, A. C. D. Newman, ed., Longman Sci. & Technical, Essex, England, 1–128.
Phillips, W. R. and Griffen, D. T. (1981) Optical Mineralogy— The Nonopaque Minerals: W. H. Freeman, San Francisco.
Rowell, D. L. and Dillon, P. J. (1972) Migration and aggregation of Na and Ca clays by the freezing of dispersed and flocculated suspension: J. Soil. Sec. 23, 442–447.
Saunders, R. S., Fanale, F. P., Parker, T. J., Stephens, J. B., and Sutton, S. (1986) Properties of filamentary sublimation residues from dispersions of clay in ice: Icarus 66, 94–104.
Soil Survey Staff (1990) Keys to Soil Taxonomy, 4th ed: SMSS Technical Monograph 6, Virginia Polytechnical Institute & State Univ., Blacksburg, Virginia.
Sudo, T. and Takahashi, H. (1956) Shapes of halloysite particles in Japanese clays: Clays & Clay Minerals 4, 67–79.
Stoiber, R. E. and Morse, S. A. (1981) Microscopic Identification of Crystals: R. E. Krieger Publ. Co., Huntington, New York.
Taszaki, K. (1982) Analytical electron microscopic studies of halloysite formation processes—Morphology and composition of halloysite: in Proc. Int. Clay Confi, Italy, 1981, Elsevier, Amsterdam, 573–584.
van der Marel, H. W. and Krohmer, P. K. (1969) O-H stretching vibrations in kaolinite and related minerals: Cont. Mineral. & Petrol. 22, 73–82.
Wada, K. and Yoshinaga, N. (1969) The structure of imogolite: Am. Mineral. 54, 50–71.
Wada, S. I. and Mizota, C. (1982) Iron-rich halloysite (10 Å) with crumpled lamellar morphology from Hokkaido, Japan: Clays & Clay Minerals 30, 315–317.
Whittig, L. D. and Allardice, W. R. (1986) X-ray diffraction techniques: in Methods of Soil Analysis Part I—Physical and Mineralogical Methods. No. 9, A. Klute, ed., Amer. Soc. Agron., Madison, Wisconsin, 331–362.