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Characterization by Mössbauer spectroscopy of Fe phases in highly weathered serpentinitic soil from southern Cameroon

Published online by Cambridge University Press:  09 July 2018

C. Van Cromphaut*
Affiliation:
Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
E. Van Ranst
Affiliation:
Department of Geology and Soil Science, Ghent University, Krijgslaan 281 (S8), 9000 Ghent, Belgium
V. G. De Resende
Affiliation:
Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
R. E. Vandenberghe
Affiliation:
Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
E. De Grave
Affiliation:
Department of Subatomic and Radiation Physics, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
G. Lambiv Dzemua
Affiliation:
Geovic Cameroon PLC, BP 11555, Yaounde, Cameroon

Abstract

Weathered soil material derived from tectonically emplaced serpentinized ultrabasic intrusive rocks of southern Cameroon has received considerable attention from mining companies due to its extractable-metal (i.e. Ni, Co) potential. As these cations can be incorporated into Fe oxides, it was deemed appropriate to study the mineralogical assemblage of a highly weathered serpentinite soil profile from the area. This study focuses on the different Fe-oxide phases, which were investigated using 57Fe Mössbauer spectroscopy, showing goethite and hematite as the dominant Fe oxides throughout the weathering profile. These minerals, in association with gibbsite and kaolinite, indicate an advanced degree of weathering. The clay fraction of the ‘Lower Limonite’ layer, above the saprolite and at a depth of 7 m, is very rich in goethite, whereas hematite and magnetite are almost absent. Above this layer, the hematite content in the fine-earth and clay fractions increases upwards, while the goethite content remains constant. The significant substitution and change in the particle size of the goethite and the poor crystallinity of hematite, as indicated by the hyperfine parameters and XRD, suggest that the upper material evolved under different pedological conditions compared to the deeper layers. The mixed composition of the upper layers (above 7 m), which contain muscovite and a relatively chaotic distribution of trace elements, suggests ancient mica-schist capping and possibly different cycles of erosion and pedimentation.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

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References

Baert, G., Van Ranst, E., Vandeberghe, R.E. & De Weirdt, J. (1999) Estimation of Al-for-Fe substitution in goethite by selective dissolution and Mössbauer spectroscopy in a weathering sequence on mafic rocks in the Lower Congo. Malaysian Journal of Soil Science, 3, 1127.Google Scholar
Bessoles, R. (1980) La chain Panafricaine au Cameroun, en Centrafrique, au Tchad et au Soudan en Géologie de l’Afrique. La chain Panafricaine: zone mobile d’Afrique Centrale (partie Sud et zone mobile Soudanaise). Mémoire Du Bureau de Recherches Géologiques et Minières, 92, 377 pp.Google Scholar
Cornell, R.M. & Schwertmann, U. (2003) The Iron Oxides. 2 nd edition. Wiley-VCH, Weinheim, Germany, pp. 433475 pp.CrossRefGoogle Scholar
De Grave, E. & Vandenberghe, R.E. (1986) 57Fe Mössbauer effect study of well-crystallized goethite (a-FeOOH). Hyperfine Interactions, 28, 643646.CrossRefGoogle Scholar
De Grave, E., Chambaere, D. & Bowen, L.H. (1983) Nature of the Morin transition in Al-substituted hematite. Journal of Magnetism and Magnetic Materials, 30, 349354.CrossRefGoogle Scholar
De Grave, E., Bowen, L.H., Amarasiriwardena, D.D. & Vandenberghe, R.E. (1988) 57Fe Mössbauer effect study of highly substituted aluminium hematites: determination of the magnetic hyperfine field distributions. Journal of Magnetism and Magnetic Materials, 72, 129140.CrossRefGoogle Scholar
De Grave, E., Persoons, R.M., Vandenberghe, R.E. & de Bakker, P.M.A. (1993) Mössbauer study of the high-temperature phase of Co-substituted magnetites, CoxFe3-xO4. I. ⩽ 40.04. Physical Review B, 47, 58815893.CrossRefGoogle Scholar
Eswaran, H., Stoops, G. & Sys, C. (1977) The micromorphology of gibbsite forms in soils. Journal of SoilScience, 28, 136143.Google Scholar
Herbillon, A.J. (1980) Mineralogy of Oxisols and oxic materials. Pp. 109126 in: Soils with Variable Charge (Theng, B.K.G., editor). New Zealand Society of Soil Science.Google Scholar
Ingamells, C.D. (1966) Absorptiometric methods in rapid silicate analysis. Analytica Chemica Acta, 38, 12281234.CrossRefGoogle Scholar
Lambiv Dzemua, G. (2005) Mineralogical and micromorphological characterization of weathered serpentinite from south-east Cameroon. MSc thesis, Inter-university Programme in Physical Land Resources, Ghent University, Belgium, 105 pp.Google Scholar
Mehra, D. & Jackson, M. (1960) Iron oxide removal from soils and clays by dithionite-citrate system buffered with sodium bicarbonate. In: Proceedings of the 7th Clay Conference on Clays and Clay Minerals. New York, 317327.Google Scholar
Milesi, J.P., Toteu, S.F., Deschamps, Y., Feybesse, J.L., Lerouge, C., Cocherie, A., Penaye, J., Tchameni, R., Moloto-A-Kenguemba, G., Kampunzu, H.A.B., Nicol, N., Duguey, E., Leistel, J.M., Saint-Martin, M., Ralay, F., Heinry, C., Bouchot, V., Mbaigane, J.C.D., Kula, V.K., Chene, F., Monthel, J., Boutin, P. & Cailteux, J. (2006) An overview of the geology and major ore deposits of central Africa: explanatory note for the 1:4, 000, 000 map ‘Geology and Major Ore Deposits of Central Africa’. Journal of African Earth Sciences, 44, 571595.CrossRefGoogle Scholar
Muller, J.P. & Bocquier, G. (1985) Textural and mineralogical relationships between ferruginous nodules and surrounding clayey matrices in a laterite from Cameroon. Pp. 186194 in: InternationalClay Conference. Denver, USA, (Schultz, L.G., van Olphen, H. & Mumpton, F.A., editors). The Clay Minerals Society, Bloomington, Indiana, USA.Google Scholar
Murad, E. (1998) Clays and clay minerals: what can Mössbauer spectroscopy do to help understand them. Hyperfine Interactions, 117, 3970.CrossRefGoogle Scholar
Murad, E. & Schwertmann, U. (1986) Influence of Al substitution and crystal size on the room-temperature Mössbauer spectrum of hematite. Clays and Clay Minerals, 34, 16.CrossRefGoogle Scholar
Omang, S.V. (1969) A rapid fusion method for decomposition and comprehensive analysis of silicates by atomic absorption spectrophotometry. Analytica Chemica Acta, 46, 225230.CrossRefGoogle Scholar
Qafoku, N.P., Van Ranst, E., Noble, A. & Baert, G. (2004) Variable charge soils: their mineralogy, chemistry and management. Advances in Agronomy, 84, 157213.Google Scholar
Quin, T.G., Long, G.J., Benson, C.G., Mann, S. & Williams, J.P. (1988) Influence of silicon and phosphorus on structural and magnetic properties of synthetic goethite and related oxides. Clays and Clay Minerals, 36, 165175.CrossRefGoogle Scholar
Schwertmann, U. (1964) The differentiation of iron oxide in soils by a petrochemical extraction with acid ammonium oxalate. Zeitschrift Fuer Pflanzenernaehrung Duengung, Bodenkunde, 105, 194202.CrossRefGoogle Scholar
Schwertmann, U. & Pfab, G. (1996) Structural vanadium and chromium in lateritic iron oxides: genetic implications. Geochimica et Cosmochimica Acta, 60, 42794283.CrossRefGoogle Scholar
Schwertmann, U., Friedl, J., Stanjek, H. & Schulze, D.G. (2000) The effect of clay minerals on the formation of goethite and hematite from ferrihydrite after 16 years’ ageing at 25ºC and pH 4-7. Clay Minerals, 35, 613623.CrossRefGoogle Scholar
Sieffermann, G. & Millot, G. (1969) Equatorial and tropical weathering of recent basalts from Cameroon: allophanes, halloysite, metahalloysite, kaolinite and gibbsite. Proceedings of the InternationalClay Conference, Tokyo, 1, 417430.Google Scholar
Trolard, F., Bourrie, G., Jeanroy, E., Herbillon, A.J. & Martin, H. (1995) Trace metals in natural iron oxides from laterites: a study using selective kinetic extraction. Geochimica et Cosmochimica Acta, 59, 12851297.CrossRefGoogle Scholar
Vandenberghe, R.E. & De Grave, E. (1989) Mössbauer effect studies of oxidic spinels. Pp. 59182 in: Mössbauer Spectroscopy Applied to Inorganic Chemistry (Long, G.J. & Grandjean, F., editors). Plenum Press, New York.CrossRefGoogle Scholar
Vandenberghe, R.E., De Grave, E., De Geyter, G. & Landuydt, C. (1986) Characterization of goethite and hematite in a Tunisian soil profile by Mössbauer spectroscopy. Clays and Clay Minerals, 34, 275280.CrossRefGoogle Scholar
Vandenberghe, R.E., De Grave, E., Landuydt, C. & Bowen, L.H. (1990) Some aspects concerning the characterization of iron oxides and hydroxides in soils and clays. Hyperfine Interactions, 53, 175196.CrossRefGoogle Scholar
Vandenberghe, R.E., Barrero, C.A., Da Costa, G.M., Van San, E. & De Grave, E. (2000) Mössbauer characterization of iron oxides and (oxy)hydroxides: the present state of the art. Hyperfine Interactions, 126, 247259.CrossRefGoogle Scholar
Vandenberghe, R.E., De Grave, E. & Da Costa, G.M. (2001) About the Morin transition in hematite in relation with particle size and aluminium substitution. Czechoslovak Journal of Physics, 51, 663675.CrossRefGoogle Scholar
Van Ranst, E. (1995) Rational soil management in the humid tropics. Mededelingen der Zittingen Koninklijke Academie voor Overzeese Wetenschappen, 40, 209233.Google Scholar
Van Ranst, E. & Eswaran, H. (1998) Managing red and lateritic soils of the humid tropics as related to their mineralogical and charge properties. Pp. 279291 in: Red & Lateritic Soils. Vol. 1. Managing Red and Lateritic Soils for Sustainable Agriculture (Sehgal, J., Blum, W.E. & Gajbhiye, K.S., editors). Oxford & IBH Publishing, New Delhi.Google Scholar
Van Ranst, E., Shamshuddin, J., Baert, G. & Dzwowa, P.K. (1998) Charge characteristics in relation to free iron and organic matter of soils from Bambouto Mountains, Western Cameroon. European Journal of SoilScience, 49, 243252.CrossRefGoogle Scholar
Van Wambeke, A., Eswaran, H., Herbillon, A.J. & Commerma, J. (1980) Oxisols. Pp. 325350 in: Pedogenesis and SoilTaxonomy, Part II (Wilding, L.P., Smeck, N.E. & Hall, G.F., editors). Elsevier, Amsterdam.Google Scholar
Yerima, B.P.K. & Van Ranst, E. (2005) Major Soil Classification Systems Used in the Tropics: Soils of Cameroon. Trafford Publishing, Canada, 295 pp.Google Scholar
Yongue-Fouateu, R., Ghogomu, R.T., Penaye, J., Ekodeck, G.E., Stendal, H. & Colin, F. (2006) Nickel and cobalt distribution in the laterites of the Lomié region, south-east Cameroon. Journal of African Earth Sciences, 45, 3347.CrossRefGoogle Scholar