Schwertmann U., Latham Marc. (1986). Properties of iron oxides in some New Caledonian oxisols. Geoderma, 39 (2), p. 105-123. ISSN 0016-7061.
Titre du document
Properties of iron oxides in some New Caledonian oxisols
Année de publication
1986
Type de document
Article
Auteurs
Schwertmann U., Latham Marc
Source
Geoderma, 1986,
39 (2), p. 105-123 ISSN 0016-7061
Oxisols from two toposequences of New Caledonia formed from peridotite, consist essentially of Fe oxides (goethite, hematite, maghemite). These Fe oxides were characterized by their mineralogy, crystal size and morphology, Al substitution, thermal behaviour and dissolution kinetics in 6 M HCl at 25oC. In one toposequence the samples were free of hematite (goethite only) at > 1050 m above sea level whereas at lower altitudes hematite was also present. Al substitution was generally low due to the low Al content of the peridotite, except in gibbsitic samples on rocks somewhat higher in Al. The surface areas of goethite and hematite ranged between 50 and 150 m2 g-1. Dithionite-extractable Ni and Cr were between 0.2 and 2.2 % Ni and 0.3 and 2.3 % Cr. The hematite-containing samples tended to be higher in Cr and lower in Ni, whereas the opposite held for samples containing goethite only. Maghemites had a low unit cell size (8.31-8.32 instead of 8.34-8.35 Angstrôm) which was attributed to Al substitution. Dehydroxylation temperature of goethites was weakly correlated with Al substitution. Dissolution kinetics could be described by a linear form of a modified first-order reaction with one straight line for samples containing goethite only and two lines for samples containing goethite plus hematite. (Résumé d'auteur)
Plan de classement
Constituants et propriétés des sols [068PROSOL]
Descripteurs
MINERALOGIE ; PERIDOTITE ; PROPRIETE CHIMIQUE ; PROPRIETE PHYSIQUE ; OXISOL ; OXYDE DE FER
