Evolution and alteration in situ of a massive iron duricrust in Central Africa

Bitom, Dieudonné; Volkoff, Boris; Abossolo-Angue, Monique

doi:10.1016/s0899-5362(03)00044-7

Cited by 31 publications

(25 citation statements)

References 11 publications

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“…Covering the entire upslope of the interfluve, they are constituted by duricrust blocks, nodules and ferruginous pebbles buried in a fine loose clayey matrix. Many authors documented these materials as a degradation facies from a continuous duricrust in the humid tropical zone [6,41,[45][46][47][48][49][50][51].…”

Section: The Iron Glaebular Horizonsmentioning

confidence: 99%

“…These kaolinite minerals, associated with iron, generally show well defined forms [16,38,61,62]. All these forms of iron constitute one of the most marked features of tropical plateau ecosystems and are commonly reported in the humid tropical zones [8,38,41,[45][46][47]61]. They enabled one to refer to those landscapes as ``iron landscapes´´ [3].…”

Section: Influence Of Altitude On the Petrology And Geochemistry Of Tmentioning

confidence: 99%

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Influence of Altitude on the Petrological Features of a Soil Climosequence in the Humid Tropical Zone of Cameroon

Bitom¹

2013

TOGEOJ

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Although lateritic soils are well documented in the humid tropical zone, work on adiabatic effect, which imposes local climatic variations with increasing altitude, has received very little attention in this zone. The aim of this work was to study and specify a soil climosequence in the humid tropical zone of Cameroon and to show the influence of altitude on the geochemical functioning of tropical soils. The work was done in the field and completed by a battery of laboratory analyses. The results enabled the definition of a soil climosequence for the humid tropical zone in Cameroon. This climosequence is marked by soils whose evolution is conditioned by the geochemistry of iron, silicon and aluminium. In the plateau ecosystems (500-800 m altitude), iron is expressed either as hardened materials (e.g. ferruginous nodules or duricrust) or light patches on the soils, while silicon and aluminium are combined as kaolinite. In the high plateaus (800-2000 m altitude), soil evolution is dominated by aluminium geochemistry, where aluminium forms gibbsite (either indurated or loose) often associated with small amounts of goethite and hematite. Finally, in the mountainous massifs (> 2000 m altitude), soil evolution is controlled by silica geochemistry, where silica is combined with amorphous aluminium to form allophane. In this soil, the presence of a dark and thick humiferous andosolic horizon in the upper part of the profile is very remarkable. Overall, this soil climosequence reflects geochemical functioning processes which grade with altitude in the humid tropical zone of Cameroon, similar to that commonly observed under the temperate climate. This general scheme could be extrapolated to other humid tropical regions with similar climatic and relief conditions as those observed in Cameroon. However, this general tendency often includes site-specific modifications caused by human activity and local variations of environmental conditions.

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Section: The Iron Glaebular Horizonsmentioning

confidence: 99%

Section: Influence Of Altitude On the Petrology And Geochemistry Of Tmentioning

confidence: 99%

Influence of Altitude on the Petrological Features of a Soil Climosequence in the Humid Tropical Zone of Cameroon

Bitom¹

2013

TOGEOJ

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“…This part of the Pan-African metamorphic belt has been subjected to various weathering processes that have controlled the distribution of major and trace elements (Temgoua et al, 2002;Bitom et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

Mobilization and redistribution of major and trace elements in two weathering profiles developed on serpentinites in the Lomié ultramafic complex, South-East Cameroon

Ndjigui

Paul

Bitom

et al. 2008

Journal of African Earth Sciences

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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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Evolution and alteration in situ of a massive iron duricrust in Central Africa

Cited by 31 publications

References 11 publications

Influence of Altitude on the Petrological Features of a Soil Climosequence in the Humid Tropical Zone of Cameroon

Influence of Altitude on the Petrological Features of a Soil Climosequence in the Humid Tropical Zone of Cameroon

Mobilization and redistribution of major and trace elements in two weathering profiles developed on serpentinites in the Lomié ultramafic complex, South-East Cameroon

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

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