Bauxites. Developments in Soil Science series

Valeton, Ida; Douglas, L. A.

doi:10.1097/00010694-197312000-00010

Cited by 32 publications

(54 citation statements)

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“…Several studies have been carried out in Africa and Cameroon on the vertical organization and evolution of bauxite duricrust in the landscape, these bauxites have been develop on very thick mantle of alteration which forms old residual surfaces Valeton (1972Valeton ( & 1981. The bauxites of Bangam are arranged in three levels, namely, the upper level, the intermediate level and the lower level qualify as bowés by Morrin (1980) and Momo et al (2011).…”

Section: Relationship Between Bauxite and Geomorphologymentioning

confidence: 99%

“…The bauxites of Bangam show that they are still rich in iron and alumina, the high contents of iron oxyhydroxides and alumina in some facies indicate just the formation of these minerals from a basaltic parent rock and especially during the phenomenon of relative accumulation (Annand & Butt, 2010;Mc Queen & Scott 2008). Valeton (1972Valeton ( & 1981 describes it as protobauxites that have been set up under a process of allitization and monosiallitization due to an abundance of rain (1712.10mm) or because of the hydrographic network, the steep inclined slopes which favoured the leaching of the environment, Momo et al (2011), Aristizabal et al (2005. …”

Section: Mineralogy and Geochemistry Of Bauxite In Bangam Localitymentioning

confidence: 99%

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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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Section: Relationship Between Bauxite and Geomorphologymentioning

confidence: 99%

Section: Mineralogy and Geochemistry Of Bauxite In Bangam Localitymentioning

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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“…A formação das crostas pressupõe longo processo de lixiviação, acúmulo de ferro e alumínio, clima sazonal e estabilidade tectônica (Valeton 1972, Bardossy & Aleva 1990. Na Amazônia, o início da lateritização é atrelado a idades entre 60 e 70 Ma obtidas por Vasconcelos et al (1994), Ruffet et al (1996) (Costa 1997, Kostschoubey et al 2005.…”

Section: Associações Geoquímicasunclassified

Mineralogia, geoquímica e evolução da lateritização em Apuí, sudeste do Amazonas

Albuquerque

Horbe

2015

Braz. J. Geol.

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RESUMO:Análises químicas, DRX e MEV realizadas em bauxitas, crostas ferruginosas e ferro-alumino-silicosas, aliadas ao estudo do relevo, tiveram por objetivo discutir os processos que levaram a formação e preservação das crostas lateríticas ao longo do tempo geológico no sudeste do Amazonas. As crostas são maciças, pisolíticas, brechóides e vermiformes, sustentam platôs e colinas com altitudes entre 200 e 320 m e 140 e 200 m, e desenvolveram-se a partir de rochas ígneas e sedimentares dos grupos Colíder e Alto Tapajós e do Supergrupo Sumaúma. A correlação entre os produtos da lateritização e as rochas identificou três associações: (1) congrega arenitos, vulcânicas e siltitos em razão da associação SiO 2 -Ba-Rb; (2) agrupa bauxitas e solos relacionados Al 2 O 3 -TiO 2 -PF-Y-Ta-Nb-U--Th-Ga-Hf-Zr-ETR; (3) reúne a bauxita pisolítica, crostas ferruginosas e ferro-alumino-silicosas vinculadas a Fe 2 O 3 -Ag-As-Ni-Pb-V. Aspectos geoquímicos e a ausência de seixos quartzosos indicam que o protólito da bauxita maciça e do solo sobrejacente é a rocha vulcânica, enquanto a bauxita pisolítica e a crosta vermiforme ferro-alumino-silicosa derivam dos arenitos do Supergrupo Sumaúma, e as demais crostas ferruginosas a ferro-alumino-silicosas correlacionam-se ao Grupo Alto Tapajós. As ações erosivas foram facilitadas pela incisão dos rios Aripuanã, Acari e Sucunduri; pelo condicionamento de grábens e horsts; e pelas épocas mais secas no Quaternário Amazônico, que resultaram em relevo dissecado, perfis truncados, formação de linhas de pedra e solo pouco espesso. PALAVRAS-CHAVE:Bauxita; Crosta laterítica; Geoquímica; Geomorfologia. (3) ABSTRACT: Chemical analysis, XRD and SEM carried out in bauxites, Fe-rich and siliceous Fe-Al duricrusts of southeast of Amazonas state, associated to relief study, aimed to discuss the process that led to the formation and preservation of crusts through the geologic time. The crusts are massive, pisolitic, fragmental and vermiform textures, and support plateaus and hills with elevation between 200 to 320 m and 140 to 200 m, and developed from igneous and sedimentary rocks of Colíder and Alto Tapajós Group's and Supergroup Sumaúma. The correlation among lateritization products and rocks were defined for three main geochemistry associations: (1) that includes sandstones, volcanics and siltstones due to the association SiO 2 -Ba-Rb; (2) gathers bauxites and soils related to Al 2 O 3 -TiO 2 -PF-Y-Ta-Nb-U- 569 INTRODUÇÃOAs paisagens lateríticas desenvolvidas ao longo do cinturão intertropical entre as latitudes 35°N e 35°S, onde a temperatura, em geral, é superior a 20°C e a umidade supera 1.200 mm/ano, são interpretadas como produto final de um longo tempo de exposição subaérea das rochas (Anand & Paine 2002). Nessas condições desenvolvem-se crostas lateríticas ferruginosas, bauxíticas, fosfáticas, niquelíferas e manganesíferas que constituem importantes jazidas minerais (Bardossy & Aleva 1990, Costa 1990, Costa 1997, Lucas 1997, Boulangé & Carvalho 1997, Horbe & Costa 1999, Kostchoubey et al. 2005...

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“…The stability and conditions of formation of boehmite and diaspore and their genetic relationship to one another and to kaolinite are only poorly understood, despite the many studies on these subjects. Diaspore itself has been reported in both metamorphosed and unmetamorphosed karst-and laterite-type bauxite deposits (Fox, 1932;Beneslavsky, 1963;Valeton, 1972;Bhrdossy, 1982), but in contrast to earlier ideas that it formed only under metamorphic conditions (Gorecky et al, 1949;Ervin Dangi6 Clays and Clay Minerals to be a relatively simple process ofmetasomatic resilicification (Keller, 1962;Keller and Clarke, 1984;Valeton, 1972;B~rdossy, 1982). Dangi6 (1985a), however, showed that for bauxite in the Vlasenica region of Yugoslavia, kaolinization of the matrix material took place in a complex manner, involving both Si-metasomatism and Al-remobilization.…”

Section: Introductionmentioning

confidence: 97%

Kaolinization of Bauxite: A Study of the Vlasenica Bauxite Area, Yugoslavia. II. Alteration of Oolites

Dangić

1988

Clays and clay miner.

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Abstract--During the epigenetic alteration of boehmitic karstic bauxite in the Vlasenica region of Yugoslavia, which was caused by siliceous water descending through the deposit by means of cracks, fissures, etc., oolites were less altered compared with the coexisting matrix material, which was intensely kaolinized. The following zonal alteration pattern of the oolites was identified: a diaspore enrichment zone, followed by a diaspore-boehmite enrichment zone, and then the original bauxite. Considering this alteration pattern and that determined previously for the matrix material, the following overall pattern of alteration was established: a kaolinite-diaspore zone, followed by a boehmite-diaspore zone, and then the original bauxite. The alteration solutions reacted with the bauxite to form solution-matrix and solution-oolite subsystems, which were characterized by different types of diffusion and geochemistry.In the kaolinite-diaspore zone Si-metasomatism kaolinized the matrix, and excess A1 partly migrated into the oolites, forming diaspore, and outward into the bauxite. The latter Al-remobilization resulted in a transition zone, in which new boehmite was formed in both the matrix and the oolites, and diaspore only in the oolites. Thermodynamic models of oolites and whole bauxite alterations were established, on the basis of stability diagrams calculated for the mineral assemblages of both the oolites and the matrix, in the alteration zones and in the deposit as a whole. Based on these models, the genesis of the diaspore and the relationship of diaspore-boehrnite-kaolinite assemblages in natural systems at low temperature and low pressure can be described. Key Words--Aluminum, Bauxite, Boehmite, Diaspore, Kaolinization, Oolites. Rezime--Tokom epigenetske alteracije bemitskih karsnih boksita u podru~ju Vlasenice, izazvane perkolacijom voda obogarenih rastvorenom silicijom koje su ponirale kroz pukotine, rasedne zone i sl., ooliti su slabije alterisani u poredjenju sa koegzistentnom osnovom kojaje intenzivno kaolinisana. Identifikovan je slederi tip zonarne alteracije za oolite: zona obogarenja dijasporom, iza koje slede zona obogarenja dijasporom i bemitom i zatim originalni boksit. Na osnovu razmatranja ovog tipa alteracije i tipa alteracije za materijal osnove, ustanovljen je slederi tip alteracije boksita kao celine: kaolinitsko-dijasporska zona, iza koje slede bemitsko-dijasporska zona i zatim originalni boksit. Alteracioni rastvor je reagovao sa boksitom obrazujuri kompleksan sistem, koji se sastojao od dva podsistema: rastvor-materijal osnove i rastvor-ooliti, koji su se medju sobom razlikovali kako po modelima difuzije tako i po geohemijskim karakteristikama.U kaolinsko-dijasporskoj zoni Si-metasomatizam je doveo do kaolinizacije materijala osnove, a vi~ak A1 je delom migrirao kako u koegzistentne oolite, obrazujuri u njima dijaspor, tako i dublje u boksit. Remobilizacija A1 dublje u boksit dovela je do obrazovanja prelazne zone, u kojoj se obrazovao bemit i u osnovi i u oolitima, i dijaspor samo u ooli...

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Bauxites. Developments in Soil Science series

Cited by 32 publications

References 0 publications

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

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

Mineralogia, geoquímica e evolução da lateritização em Apuí, sudeste do Amazonas

Kaolinization of Bauxite: A Study of the Vlasenica Bauxite Area, Yugoslavia. II. Alteration of Oolites

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