Abstract
Clay (<2 μm) and fine silt (2–20 μm) fractions of twenty seven soil samples from eight tropical ferruginous profiles of the Mysore Plateau (India) were analysed for kaolinite by dehydroxylation and selective dissolution. The considerable amounts of iron extracted by the procedure and the closeness of the SiO2/R2O3 molar ratios (2·00–2·18) to the ideal value of 2·00 indicated that iron was a structural constituent of the kaolinites. The calculated unit cell cation composition of the kaolinites showed a substitution of 0·11–0·82 atoms of Fe(III) for Al in every four octahedral sites. The kaolinites in these soils appear to be products of crystallization from weathering solutions.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Bailey, S. W. and Langsten, R. B. (1969) Anauxite and kaolinite structures identical: Clays and Clay Minerals 17, 241–243.
Brindley, G. W. and Robinson, K. (1946) Structure of kaolinite: Mineral Mag. 27, 242–253.
Briner, G. P. and Jackson, M. L. (1970) Mineralogical analysis of clays in soils developed from basalts in Australia: Israel J. Chem. 8, 487–500.
El-Attar, H. A. and Jackson, M. L. (1973) Montmorillonite soils developed in Nile River sediments: Soil Sci. 116, 191–201.
Grim, R. E. (1968) Clay Mineralogy. McGraw-Hill, New York.
Hashimoto, I. and Jackson, M. L. (1960) Rapid dissolution of allophane and kaolinite-halloysite after dehydration: Clays and Clay Minerals 7, 102–113.
Hendricks, S. B. (1936) Concerning the crystal structure of kaolinite, Al2O3, 2SiO2, 2H2O, and the composition of anauxite: Z. Krist. 95, 247–252.
Jackson, M. L. (1969) Soil Chemical Analysis—Advanced Course. Published by the author, University of Wisconsin, Madison, Wisconsin.
Jackson, M. L. (1958) Soil Chemical Analysis. Prentice-Hall, Englewood Cliffs, New Jersey.
Kelley, W. P. (1955) Interpretation of chemical analyses of clays: Clays and Clay Tech. 1, 92–94.
Krishna Murti, G. S. R., Moharir, A. V. and Sarma, V. A. K. (1970) Spectrophotometric determination of iron with orthophenanthroline: Microchem. J. 15, 585–589.
Krishna Murti, G. S. R., Sarma, V. A. K., and Rengasamy, P. (1974) Spectrophotometric determination of aluminium with aluminon: Indian J. Tech. 12, 270–271.
Langston, R. B. and Jenne, E. A. (1964) NaOH dissolution of some oxide impurities from kaolins: Clays and Clav Minerals 12, 633–647.
Langston, R. B. and Pask, J. A. (1968) The nature of anauxite: Clays and Clay Minerals 16, 425–436.
MacKenzie, K. J. D. (1968) A Mössbauer study of the role of iron impurities in the high temperature reactions of kaolinite minerals: Clay Minerals 8, 151–160.
Maksimovič, B. and Crnkovič, B. (1968) Halloysite and kaolinite formed through alteration of ultramafic rocks: Rept. lird Intern. Geol. Congr. Czechoslovakia Proc. Symposium I (Genesis of the kaolin deposits), pp. 95–105.
Mehra, O. P. and Jackson, M. L. (1960) Iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate: Clays and Clay Minerals 7, 317–327.
Rengasamy, P. (1973) Mineralogy, genesis and physical properties of a latosolic association near Nandi Hills, Mysore: Ph.D. Thesis, Indian Agricultural Research Institute, New Delhi, India.
Rengasamy, P., Sarma, V. A. K. and Krishna Murti, G. S. R. (1975) Quantitative mineralogical analysis of soil clays containing amorphous materials: a modification of the Alexiades and Jackson procedure: Clays and Clay Minerals 23, 78–80.
Robertson, R. H. S., Brindley, G. W. and Mackenzie, R. C. (1954) Mineralogy of kaolin clays from Pugu, Tanganyika: Am. Miner. 39, 118–139.
Ross, C. S. and Kerr, P. F. (1931) The kaolin minerals: U.S. Geol. Survey Prof Paper 165E., 151–176.
Roth, C. B., Jackson, M. L., Lotse, E. G. and Syers, J. K. (1968) Ferrous ferric ratio and CEC changes on deferration of weathered micaceous vermiculite: Israel J. Chem. 6, 261–273.
Schofield, R. K. (1949) Effect of pH on electric charges carried by clay particles: J. Soil Sci. 1, 1–8.
Sumner, M. E. (1963) The effect of iron oxides on positive and negative charges in clays and soils: Clav Minerals Bull. 5, 218–226.
Weaver, C. E. (1968) Electron microprobe study of kaolin: Clays and Clay Minerals 16, 187–189.
Weaver, C. E., Wampler, J. M. and Pecuil, T. E. (1967) Mössbauer analysis of iron in clay minerals: Science 156, 504–508.
Youell, R. F. (1958) Isomorphous replacement in the kaolin group of minerals: Nature, Lond. 181, 557–558.
Author information
Authors and Affiliations
Additional information
Complete description of the soil profiles was reported by Rengasamy (1973).
Rights and permissions
About this article
Cite this article
Rengasamy, P., Krishna Murti, G.S.R. & Sarma, V.A.K. Isomorphous Substitution of Iron for Aluminium in Some Soil Kaolinites. Clays Clay Miner. 23, 211–214 (1975). https://doi.org/10.1346/CCMN.1975.0230308
Received:
Published:
Issue Date:
DOI: https://doi.org/10.1346/CCMN.1975.0230308