Hostname: page-component-cd9895bd7-7cvxr Total loading time: 0 Render date: 2024-12-26T08:45:20.040Z Has data issue: false hasContentIssue false

Oriented overgrowth of acicular maghemite crystals on quartz

Published online by Cambridge University Press:  09 July 2018

M. M. Abreu
Affiliation:
Instituto Superior de Agronomia, Tapada da Ajuda, 1399 Lisboa
M. O. Figueiredo
Affiliation:
Centro de Cristalografia e Mineralogia, IICT, 1000 Lisboa
J. C. Waerenborgh
Affiliation:
Departamento de Quimica ICEN-LNETI, 2685 Sacavém, Portugal
J. M. P. Cabral
Affiliation:
Departamento de Quimica ICEN-LNETI, 2685 Sacavém, Portugal

Abstract

Maghemite with acicular morphology occurs as an oriented growth on fresh quartz surfaces in the magnetic sandy fraction of the B horizon of a Typic Rhodoxeralf from southern Portugal. The maghemite was characterized by Mössbauer spectroscopy, X-ray diffraction and electron microscopy (scanning and transmission), and on the basis of a structural similarity between quartz and maghemite, a mechanism has been proposed for the formation of the oriented overgrowth. Correlation with an interpretative chemical model is discussed, assuming active sites over quartz surfaces. Infrared absorption data agree with the proposed models.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1988

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Abreu, M.M. & Robert, M. (1985) Characterization of maghemite in B horizons of three soils from Southern Portugal. Geoderma 36, 97–108.Google Scholar
Abreu, M.M. & Robert, M. (1987) Relations maghemite-quartz. Etudes dans le milieu naturel (sols Rouges du Portugal) eten conditions experimentales. Pp. 165170 in rPwc. VIIth Int. Work. Meet. Soil Micromorphol.(Fedoroff, N., Bresson, L.M. & Courty, M.A., editors). AFES Paris.Google Scholar
Annersthn, H. & Hafner, S.S. (1973) Vacancy distribution in synthetic spinels of the series Fe3O4-γFe2O3 . Zeit. kristallog. 137, 321–340.Google Scholar
Figueiredo, M.O. (1977) Estabilidade e estrutura cristalina: o caso-tipo das fases da silica. Com. Serv. Geol. Port. LXII, 19–34.Google Scholar
Greenwood, N.N. & Gibb, T.C. (1971) Mossbauer Spectroscopy, pp. 239254. Chapman & Hall, London.Google Scholar
Mackay, A.L. (1960) β-Ferric oxyhydroxide. Mineral. Mag. 32, 545–557.Google Scholar
McDonald, R.S. (1958) Surface functionality of amorphous silica by infrared spectroscopy. J. Phys, Chem. 62, 1168–1178.Google Scholar
Schwertmann, U. & Taylor, R.M. (1977) Iron oxides. Pp. 145180 in: Minerals in Soil Environments (Dixon, J.B. & Weed, S.B., editors). Soil Sci. Soc. Am., Madison, Wisconsin.Google Scholar
Schwertmann, U. & Fechter, M. (1984) The influence of aluminum on iron oxides, XI. Aluminum-substituted maghemite in soils and its formation. Soil Sci. Soc. Am. J. 48, 1462–1463.Google Scholar
Stone, A.J. (1967) Least squares fitting of Mossbauer spectra. Appendix to: Bancroft G.M., Maddock A.G., Ong W.K., Prince R.H. & Stone A.J. (1967), J. Chem. Soc. (A), 1966-1971.Google Scholar
Stumm, W. (1986) Coordinative interactions between soil solids and water–an aquatic chemist's point of view. Geoderma 38, 19–30.Google Scholar
Taylor, R.M. & Schwertmann, U. (1974) Maghemite in soils and its origin. II Maghemite synthesis at ambient temperature and pH l.Clay Miner. 10, 299–310.Google Scholar
Tøpsoe H., , Dumesic, J.A. & Boudart, M. (1974) Mossbauer spectra of stoichiometric and nonstoichiometric Fe304 microcrystals. J. Physique (Paris) 35 (12-C6), 411–413.Google Scholar
Van Oosterhout, G.W. (1960) Morphology of synthetic submicroscopic crystals of a and yFeOOH and of «Fe2O3 prepared from FeO.OH. Acta Cryst. 13, 932–935.Google Scholar