Abstract
The weathering products of primary biotite, chlorite, magnetite, and almandine in mica gneiss and schist in the North Carolina Blue Ridge Front were determined. Sand-size grains of biotite, the most abundant, readily weathered mineral in the parent rock, have altered to interstratified biotite/vermiculite, vermiculite, kaolinite, and gibbsite in the saprolite and soil. Fe2+-chlorite in the parent rock was relatively resistant to chemical weathering, which appears to be confined to the external surfaces of particles. Magnetite grains in the saprolite are essentially unaltered, but those in the soil contain abundant crys-tallographically controlled etch pits and are coated with oxidation crusts. Almandine altered to goethite, hematite, and gibbsite as the rock weathered to saprolite. Extensively weathered almandine grains were found to contain etch pits and what appeared to be oxide coatings. Apparently, a rapid release of Fe during weathering produced hematite, whereas slower release of Fe favored the formation of goethite.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Amarasiriwardena, D. D., DeGrave, E., Bowen, L. H., and Weed, S. B. (1986) Quantitative determination of aluminum-substituted goethite-hematite mixtures by Möss-bauer spectroscopy: Clays & Clay Minerals 34, 250–256.
Amthauer, G., Annersten, H., and Hafner, S. S. (1976) The Mössbauer spectrum of 57Fe in silicate garnets: Z. Kristal-logr. 143, 14–55.
Bain, D. C. (1977) The weathering of chloritic minerals in some Scottish soils: J. Soil Sci. 28, 144–164.
Barnhisel, R. I. (1977) Chlorites and hydroxy interlayered vermiculite and smectite: in Minerals in Soil Environments, J. B. Dixon and S. B. Weed, eds., Soil Science Society of America, Madison, Wisconsin, 331–356.
Blaauw, C., Stroink, G., and Leiper, W. (1980) Mössbauer analysis of talc and chlorite: J. Phys. 41C1, 411–412.
Bowen, L. H. and Weed, S. B. (1984) Mössbauer spectroscopy of soils and sediments: in Chemical Mössbauer Spectroscopy, R. H. Herber, ed., Plenum, New York, 217–242.
Buoi, S. W. and Fadness, D. M. (1961) New method of impregnating fragile material for thin sectioning: Soil Sci. Soc. Amer. Proc. 25, p. 253.
Buoi, S. W., Hole, F. D., and McCracken, R. J. (1980) Soil Genesis and Classification: Iowa State University Press, Ames, Iowa, 406 pp.
Douglas, L. A. (1977) Vermiculites: in Minerals in Soil Environments, J. B. Dixon and S. B. Weed, eds., Soil Science Society of America, Madison, Wisconsin, 259–292.
Fanning, D. S. and Keramidas, V. Z. (1977) Micas: in Minerals in Soil Environments, J. B. Dixon and S. B. Weed, eds., Soil Science Society of America, Madison, Wisconsin, 195–258.
Gilkes, R. J. and Suddhiprakarn, A. (1979) Magnetite alteration in deeply weathered adamellite: J. Soil Sci. 30, 357–361.
Golden, D. C., Bowen, L. H., Weed, S. B., and Bigham, J. M. (1979) Mössbauer studies of synthetic and soil-occurring aluminum substituted goethites: Soil Sci. Soc. Amer. J. 43, 802–808.
Graham, R.C. (1986) Geomorphology, mineral weathering, and pedology in an area of the Blue Ridge Front, North Carolina: Ph.D. dissertation, North Carolina State University, Raleigh, North Carolina, 196 pp.
Graham, R. C., Weed, S. B., Bowen, L. H., Amarasiriwardena, D. D., and Buoi, S. W. (1989) Weathering of iron-bearing minerals in soils and saprolite on the North Carolina Blue Ridge Front: II. Clay mineralogy: Clays & Clay Minerals 37, 29–40.
Greig, J. W., Posnjak, E., Merwin, H. E., and Sosman, R. B. (1935) Equilibrium relationships of Fe3O4, Fe2O3, and oxygen: Amer. J. Sci. 230, 239–316.
Grüner, J. W. (1926) Magnetite-martite-hematite: Econ. Geol. 21, 375–393.
Hargrove, R. S. and Kundig, W. (1970) Mössbauer measurements of magnetite below the Verwey Transition: Solid State Comm. 8, 303–308.
Harris, W. G., Zelazny, L. W., and Bloss, F.D. (1985) Biotite kaolinization in Virginia Piedmont soils: II. Zonation in single grains: Soil Sci. Soc. Amer. J. 49, 1297–1302.
Losche, C. K., McCracken, R. J., and Davey, C. B. (1970) Soils of steeply sloping landscapes in the southern Appalachian Mountains: Soil Sci. Soc. Amer. Proc. 34, 473–478.
Murad, E. and Bowen, L. H. (1987) Magnetic ordering in Al-rich goethites: Influence of crystallinity: A mer. Mineral. 72, 194–200.
Murad, E. and Schwertmann, U. (1986) Influence of Al substitution and crystal size on the room-temperature Mössbauer spectrum of hematite: Clays & Clay Minerals 34, 1–6.
Murad, E. and Wagner, F. E. (1987) The Mössbauer spectrum of almandine. Phys. Chem. Minerals 14, 264–269.
Papamarinopoulos, S., Readman, P. W., Maniatis, Y., and Simopoulos, A. (1982) Magnetic characterization and Mössbauer spectroscopy of magnetic concentrates from Greek lake sediments: Earth Planet. Sci. Letters 57, 173–181.
Rebertus, R. A., Weed, S. B., and Buoi, S. W. (1986) Transformations of biotite to kaolinite during saprolite-soil weathering: Soil Sci. Soc. Amer. J. 50, 810–819.
Ross, G. J. and Kodama, H. (1974) Experimental transformation of a chlorite into a vermiculite: Clays & Clay Minerals 22, 205–211.
Sawhney, B. L. (1977) Interstratification in layer silicates: in Minerals in Soil Environments, J. B. Dixon and S. B. Weed, eds., Soil Science Society of America, Madison, Wisconsin, 405–434.
Schwertmann, U. (1985) The effect of pedogenic environments on iron oxide minerals: in Advances in Soil Science, Vol. 1, Springer-Verlag, New York, 170–200.
Stuckey, J. L. (1965) North Carolina: Its Geology and Mineral Resources: North Carolina Dept. Conserv. Dev., Raleigh, North Carolina, 550 pp.
Velbel, M. A. (1984) Natural weathering mechanisms of almandine garnet. Geology 12, 631–634.
Walker, A. L. (1983) The effects of magnetite on oxalate-and dithionite-extractable iron: Soil Sci. Soc. Amer. J. 47, 1022–1026.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Graham, R.C., Weed, S.B., Bowen, L.H. et al. Weathering of Iron-Bearing Minerals in Soils and Saprolite on the North Carolina Blue Ridge Front: I. Sand-Size Primary Minerals. Clays Clay Miner. 37, 19–28 (1989). https://doi.org/10.1346/CCMN.1989.0370103
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1346/CCMN.1989.0370103