Démantèlement des paysages cuirassés anciens en zones forestières tropicales d'Afrique centrale : formation d'accumulations ferrugineuses actuelles en bas de versant

Temgoua, Émile; Bitom, Dieudonné; Paul, Bernard; Lucas, Yves; Pfeifer, Hans-Rudolf

doi:10.1016/s1631-0713(02)01793-5

Cited by 20 publications

(21 citation statements)

References 11 publications

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“…Contrary to the studied soils, the two generations of nodules are present in the Ekoumdoum soil profile, developed on garnet-rich migmatitic gneiss ( Figure 9). However, "second generation" nodules are more frequent in humid tropical zone (Tardy, 1993;Beauvais and colin, 1993;Beauvais and Tardy, 1993;Temgoua et al, 2002;Bitom et al, 2004;Beauvais, 2009;Tsozué et al, 2012). Beside the garnet grain, other primary minerals exhibit an opposite evolution.…”

Section: Discussionmentioning

confidence: 99%

Tropical chemical weathering of a garnet rich micaschist in the rainforest zone of Cameroon

Tsozué

Yongue-Fouateu

2017

Eurasian Journal of Soil Science (Ejss)

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Article Info Received : 22.03.2016 Accepted : 17.05.2016 Soils developed on garnet-rich micaschist in the Southern Cameroon plateau were investigated. Morphologically, two weathering materials constituted the study profile, fine earth and nodules. Each material has a singular evolution from the coarse saprolite to the upper set of clayey and loose horizons. There is Al2O3 enrichment in the fine earth concomitantly to Fe2O3, Na2O and K2O enrichment in nodules in major elementAl2O3 variation diagrams. A-CN-K and A-CNK-FM diagrams show a progressive depletion of Al in nodules concomitantly to an enrichment of this element in the fine earth. Three pedogenetic processes emerge from the evolution of weathering products. There is a ferruginization process whose importance increases from the coarse saprolite to the upper set of clayey and loose horizons, giving rise to the formation of dense nodules composed of hematite, goethite and gibbsite. This ferruginization occurs concomitantly with a desaluminization process, which causes Al2O3 depletion in nodules. These nodules are formed by the process of induration where the hydrated amorphous hydroxide and oxides are dehydrated to their crystalline oxide form, due to condensation. In addition, there is aluminization, which occurs in the fine earth, leading to the development of a red clayey material composed of kaolinite and gibbsite.

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Section: Discussionmentioning

confidence: 99%

Tropical chemical weathering of a garnet rich micaschist in the rainforest zone of Cameroon

Tsozué

Yongue-Fouateu

2017

Eurasian Journal of Soil Science (Ejss)

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“…The degradation of bauxites is favoured by the tropical humid climate and by the set of this brittle tectonic influencing considerably the shape of the bauxites (Leprun, 1977;Morin, 1980). For King (1967), the African morphologies depend on the progressive erosion and peneplanation which are favoured by the hydrographic network which generally get along with the faults (Nono et al, 2001) and are responsible for the reduction and variations of the thickness of the duricrust 13.2m above the plateaus, 6 to 5m on the flanks of hills and plateaus, (Temgoua et al, 2002;Bitom et al, 2003). According to Hieronymus, (1972), the bauxitic surfaces of Bangam have been cut by the hydrographic network, which has left glaciers and ridge lines, separated by numerous valleys.…”

Section: Relationship Between Bauxite and Geomorphologymentioning

confidence: 99%

Mineralogical, Geochemical and Distribution Study of Bauxites in the Locality of Bangam and Environs (West Cameroon)

Sojien¹,

Mamdem²,

Wouatong³

et al. 2018

ESR

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The bauxite duricrust in the Bangam and surroundings is classified into three major storey levels as follows: the upper level on top of the plateaus where the continuous bauxites outcrop in slabs over distances of about 1 km, the intermediate level on top and at the flanks of the hills where the bauxites flush in metric blocks, the lower level at the talwegs where bauxites duricrust are gravels. The average thickness of the duricrust is 9.6m and extends over an area of about 9.5km 2 . Five types of facies are encountered here: nodular, pisolitic, pseudobreccia, vacuolar and massive. These different facies were carried out by X-ray fluorescence spectrometry, X-ray diffractometric, thermal analysis (ATD / ATG) and by polarizing microscope observation. The results of these analyses show that, gibbsite is the dominant mineral; kaolinite, anatase, hematite, goethite, magnetite and ilmenite are also present. The chemical composition of the major elements that characterize bauxites are 38-60% Al 2 O 3 ; 2 -22% SiO 2 and 9-42% Fe 2 O 3 . These values are almost similar to those obtained in Doumbouo-Fokoué, Ghana, Ngaoundal, and Minim-Martap precisely at Briskok prospect. The different minerals paragenesis and geochemistry data show that, the Bangam locality is a bauxite ore deposit in spite of a high content of iron and silicate of some facies, nevertheless, these can be used in some industries.

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“…Les paramètres impactés les plus fréquemment cités sont, par ordre d'importance : la perte de la fertilité des sols, le travail difficile de ces types de sols et le faible enracinement des cultures pouvant entrainer leur chute en cas de vent violent. Les indicateurs végétaux sont caractérisés de bio-indicateurs par des études antérieures (Chotte et al, 2001;IlboudoTapsoba et al, 2011;Ogni et al, 2014) (Temgoua et al, 2002). On peut y ajouter également des zones de pavage de cailloux et de pierres laissés en surface, une fois que les particules les plus fines du sol sont emportées par le ruissellement (Kabré, 2009).…”

Section: Perception Locale De La Dynamique Des Surfaces Cuirasséesunclassified

“…Ce constat est confirmé par l'analyse diachronique des surfaces gravillonnaires réalisée dans les deux sites. Selon des études antérieures (Alexandre, 2002;Temgoua et al, 2002) L'impact négatif de l'ensemble de ces altérites sur l'utilisation agricole des terres concernées est perçu par environ 90% des producteurs enquêtés sur les deux sites. Ces résultats sont confirmés par plusieurs travaux de recherche (Ouédraogo et al, 2001;Savadogo et al, 2011 …”

Section: Perception Locale De La Dynamique Des Surfaces Cuirasséesunclassified

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Connaissances et perceptions locales de la dynamique des cuirasses ferrugineuses: Etude de cas en zone Nord-soudanienne et Sud-soudanienne du Burkina Faso

Zerbo¹,

Nacro²,

Yao-Kouamé³

et al. 2017

Int. J. Bio. Chem. Sci

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REMERCIEMENTS Ce travail a été réalisé avec un appui financier de l'Agence Australienne pour le Développement International (AusAID) via le Conseil Ouest et Centre Africain pour la Recherche et le développement agricoles (CORAF/WECARD) à travers le projet de recherche-développement sur les "Options RESUMELa dynamique des cuirasses ferrugineuses est caractérisée par un ensemble de processus, incluant leur démantèlement, le transport des altérites provenant du démantèlement et leur dépôt en aval. Ces altérites constitueront des facteurs de marginalisation des aptitudes culturales des sols sous-jacents. La présente étude a évalué les connaissances et les perceptions locales de la dynamique des cuirasses ferrugineuses des populations de deux villages du Burkina Faso. Au total, 120 personnes ont été interviewées à travers des enquêtes individuelles. Les résultats montrent que tous les producteurs interviewés connaissent la dynamique des cuirasses ferrugineuses dans leur environnement. Ces connaissances prennent en compte les preuves de la manifestation du phénomène, qui sont constituées par la présence de zones à recouvrement gravillonnaire et de ses impacts négatifs sur les activités agricoles. L'étude fait ressortir le recours par les populations, de deux types d'indicateurs pour détecter la présence en profondeur des cuirasses ferrugineuses. Il s'agit des indicateurs végétaux et des indicateurs édaphiques. L'utilisation de ces deux types indicateurs et la référence aux dépôts gravillonnaires constituent pour les producteurs, des sources de connaissance pour comprendre et expliquer la dynamique des cuirasses ferrugineuses et leur permettent d'élaborer des stratégies pour une exploitation durable de ces espaces. © 2016 International Formulae Group. All rights reserved.Mots clés : Dépôts gravillonaires, indicateurs édaphiques, indicateurs végétaux, Burkina Faso. L. ZERBO et al. / Int. J. Biol. Chem. Sci. 10(6): 2754-2767, 2016 2755 Indigenous knowledge assessment of iron crust dynamic: case study in northsoudanian and south-soudanian zones of Burkina Faso ABSTRACTThe iron crust dynamic is characterized by a set of processes including its dismantling, dripping and gradual deposit of erosion materials along the landscape. These gravel deposits constitute a great problem for soils use in agriculture. This study aims to evaluate the set of indigenous knowledge of iron crust dynamic through individual investigation in two (02) villages in Burkina Faso. A sample of one hundred and twenty (120) persons has been interviewed. The results show that all of the interviewees use indigenous knowledge to describe and explain iron crust dynamic in their area. This indigenous knowledge is base, firstly, on herbaceous indicators and soils indicators, which allow the population to deduct the presence of iron crusts in depth, secondarily, the use of the gravel surface by people as material evidence of this dynamic. The study shows also that all the interviewees estimate that the iron crust dynamic has a negative impact on agricultural...

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Démantèlement des paysages cuirassés anciens en zones forestières tropicales d'Afrique centrale : formation d'accumulations ferrugineuses actuelles en bas de versant

Cited by 20 publications

References 11 publications

Tropical chemical weathering of a garnet rich micaschist in the rainforest zone of Cameroon

Tropical chemical weathering of a garnet rich micaschist in the rainforest zone of Cameroon

Mineralogical, Geochemical and Distribution Study of Bauxites in the Locality of Bangam and Environs (West Cameroon)

Connaissances et perceptions locales de la dynamique des cuirasses ferrugineuses: Etude de cas en zone Nord-soudanienne et Sud-soudanienne du Burkina Faso

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