Genesis of a mottled horizon by Fe-depletion within a laterite cover in the Amazon BasinGenèse d'un horizon tacheté par déferruginisation dans une couverture à latérite du Bassin amazonien |
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| Authors: | Vania Rosolen Mathieu Lamotte René Boulet Jean Trichet Olivier Rouer Adolpho José Melfi |
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| Affiliation: | 1. Universidade de São Paulo, NUPEGEL, USP / ESALQ, CP 9, 13418-900 Piracicaba SP, Brazil;2. IRD, 32, avenue Henri-Varagnat, 93143 Bondy cedex, France;3. UMR ISTO, université d''Orléans–CNRS, UFR de sciences–géologie, BP 6959, 45067 Orléans cedex 02, France |
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| Abstract: | A mottled horizon in a laterite cover (without any duricrust) was studied by microscopy and quantitative chemical microanalysis. Apart from the voids, light red spots consisting of Fe-rich particles (≈2 μm) are set in clayey plasma. Dark red spots consisted of concentrations of Fe-rich particles. These patterns are inherited. On the border of structural or biological voids, where Fe-depletion features are systematic, gray or yellow spots result from dissolution of the Fe-rich particles and impregnation of the plasma by iron, respectively. The present Fe-depletion is the dominant process that explains the mottled differentiation and the absence of lateritic duricrust. To cite this article: V. Rosolen et al., C. R. Geoscience 334 (2002) 187–195. |
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| Keywords: | microscopy scanning electron microscopy quantitative chemical microprobe iron plinthic Cambisol Brazil microscopie microscopie électronique à balayage microsonde chimique quantitative fer cambisol plinthique Brésil Géosciences de surface Pédologie Surface Geosciences Pedology |
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