Genesis of bauxite deposits in the lower Amazon Basin and Guianas coastal plain

Grubb, P. L. C.

doi:10.2113/gsecongeo.74.4.735

Cited by 37 publications

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“…Dennen & Norton (1977) foram os primeiros a sugerirem uma evolução complexa para a bauxita da região amazônica. Posteriormente, Grubb (1979) apresentou um primeiro modelo polifásico implicando períodos de podzolização e de bauxitização. , defendendo uma origem poligenética para a bauxita da região de Paragominas, propuseram as seguintes fases evolutivas: lateritização inicial, desmantelamento da laterita, bauxitização por cimentação e substituição da parte inferior do nível laterítico, formação de um horizonte de cascalho superior através do retrabaIhamento físico da crosta e, finalmente, cimentação e substituição parcial deste cascalho por gibbsita.…”

Section: Cobertura De Alteração Na Região Do Baixo-médio Amazonasunclassified

“…Por outro lado, a formação dessa cobertura foi relacionada à deposição de sedimentos continentais por Sombroek (1966), Grubb (1979), . Como as investigações detalhadas não permitiram conclusões definitivas, três hipóteses podem ser consideradas segundo Truckenbrodt et al (1991): a) formação in situ da Argila de Belterra por processos intempéricos, b) transporte lateral e deposição de material saprolítico e c) transporte vertical de material saprolítico por térmitas, embora maiores espessuras de Argila de Belterra não possam ser explicadas apenas por este processo.…”

Section: Cobertura De Alteração Na Região Do Baixo-médio Amazonasunclassified

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Cobertura Bauxítica E Origem Do Caulim Do Morro Do Felipe, Baixo Rio Jari, Estado Do Amapá

KOTSCHOUBEY

DUARTE

TRUCKENBRODT

1999

RBG

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THE BAUXITIC MANTLE AND ORIGIN OF THE KAOLIN DEPOSIT OF MORRO DO FELIPE, LOWER COURSE OF THE JARI RIVER, AMAPA STATE, NORTHERN BRAZILThe Morro do Felipe kaolin deposit, occurring on the left margin of the Jari river (Northern Brazil), constitutes the lower part of an ancient weathering profile which is bounded to a planation surface about 170 m high. The kaolin layer, up to 35 m thick, consists mainly of poorly ordered kaolinite with deferrification features and thin sand intercalations. In the lower part of the deposit, the kaolin is only slightly porous and disintegrates easily in water whereas in the upper part, it is more porous, firm, displays conchoidal fracture and resists disintegration in water. In both cases, the kaolin (mineral) is very similar to fire-clay type kaolinite. The kaolin deposit grades down into altered sandstones and mudstones, with conglomerate intercalations, of the Alter do Chao Formation and is overlain by an iron crust, lower nodular bauxite, upper nodular bauxite and a clayey overburden (Belterra Clay). The evolution of this alteration profile likely involved the following steps: 1) formation of an iron crust by podzolization or ground-water lateritization of Alter do Chao deposits; 2) regional bauxitization; 3) degradation of the bauxite horizon and formation of colluvial deposits; 4) deposition of the clayey overburden upon the colluvial deposits or directly on Alter do Chao sediments; 5) lowering of the base level and reactivation of weathering giving rise to the transformation of the overburden into a latosol (Belterra Clay) and the thickening and deferrification of the saprolite horizon which resulted in the present day kaolin deposit. As shows the evolution of the alteration profile, the Morro do Felipe kaolin represents a product of deep weathering which affected the Amazon region since the Lower Tertiary. The kaolinization, related firstly to bauxitization (Lower Tertiary) and triggered, at a later stage, by reactivation of tropical weathering (Upper Tertiary/Quaternary) and epirogenetic movements, resulted from the decomposition of clay minerals and possibly some feldspar, partial dissolution of quartz, neoformation of poorly ordered kaolinite and intense deferrification. It seems very likely that the process of kaolinization continues even today. Keywords: Bauxite profile, kaolin, Morro do Felipe, Lower Amazon region. RESUMO O depósito de caulim do Morro do Felipe, localizado na margem esquerda do baixo rio Jari, constitui a parte inferior do manto intempérico que capeia um conjunto de platôs de cerca de 170 m de altitude. Forma um pacote de até 35 m de espessura composto quase exclusivamente de caulinita, apresentando feições de desferrificação e contendo delgadas intercalações de arenito friável. Na sua parte inferior, o caulim é pouco poroso e se desagrega facilmente n'água, enquanto que na parte superior, é poroso, mais litificado, exibe fratura concoidal e não se desagrega ao contato com a água. A caulinita, em ambas as zonas, possui características próximas...

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Section: Cobertura De Alteração Na Região Do Baixo-médio Amazonasunclassified

Cobertura Bauxítica E Origem Do Caulim Do Morro Do Felipe, Baixo Rio Jari, Estado Do Amapá

KOTSCHOUBEY

DUARTE

TRUCKENBRODT

1999

RBG

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“…Vários pesquisadores sugerem diferentes origens. SOMBROEK (1966), GRUBB (1979), KOTSCHOUBEY & TRUCKENBRODT (1981), HIERO-NYMUS et al (1989) e TRUCKENBRODT et al (1991 argumentam uma origem sedimentar para esses solos, podendo estar associado a processos gravita-cionais segundo o último trabalho acima citados. ROSSETTI et al (1989) ao estudar material similar na região Bragantina (NE do Pará), incluindo as áreas de Outeiro e Mosqueiro, sugerem que sejam arenitos associados a sedimentos pós-Barreiras depositados, conforme TRUCKEM-BRODT et al (1991), por movimentos gravitacionais.…”

Section: Introductionunclassified

Solos Gerados a Partir Do Intemperismo De Crostas Lateríticas Sílico-Ferruginosas

Horbe¹,

Costa

1997

Acta Amaz.

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RESUMO-A porção superior de dois perfis lateriticos localizados nos balneáreos de Outeiro e Mosqueiro, no município de Belém (Pará-Brasil), é constituída pela crosta sílico-ferruginosa e seus fragmentos de crosta, com material areno-argiloso sobreposto formando o solo. A estrutura colunar preservada, o grau de arredondamento crescente dos fragmentos e a composição mineralógica e química demonstram que há uma passagem gradacional entre a crosta, fragmentos e o solo dos dois perfis. Assim, é possível considerar o solo desses perfis como derivado do intemperismo da crosta laterítica subjacente em condições predominantemente úmidas, superimpostas ao processo laterítico que se desenvolveu na Amazônia ate então.Palavras chaves: solos da Amazônia, latcritização, crostas ferruginosas, Argila de Bcltcrra. Soil Formation by the Weathering of Silica-Iron Lateritic Duricrust.ABSTRACT-The upper part of two lateritic profiles located in Outeiro e Mosqueiro beachs in Belém district (Pará State-Brazil) are constituted by a silicia-iron duricrust and fragments of these crust with a sand-clayey material overlying forming the soil. The collunar structure, the round up of the fragments and the similar mineralogical and chemical composition show a gradual passage between the duricrust, its fragments and soil suggesting a possibility to consider the soil as result of the weathering of the subjacent lateritic duricrust in moist climate.

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“…Irregularly ahaped 9ibbsite and Nodul., Zone (Gordon and others, 1958, Grubb, 1979, Patterson, 1971. The characteristics of these zones may change, but their general nature is quite similar from one deposit to the next.…”

Section: I>mentioning

confidence: 99%

“…The zonation seen in ferruginous bauxite deposits is roughly similar to zonation sequences seen in other laterite deposits. Relatively unweathered rock is generally overlain by a zone of slightly weathered material, then by a layer of saprolite and finally by completely weathered materials (Gordon and others, 1958, Grubb, 1979, Patterson, 1971. The characteristics of these zones may change, but their general nature is quite similar from one deposit to the next.…”

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confidence: 99%

Formation and zonation of ferruginous bauxite deposits of the Chapman quadrangle, Oregon

Marty¹

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Two major theories have been advanced to account for the scattered distribution of ferruginous bauxite deposits. Original workers proposed that ferruginous bauxite originally developed over all exposed Columbia River Basalt in western Oregon and was subsequently removed by erosion. Studies which followed have suggested that it may be locally favorable conditions, especially of drainage, which are responsible for deposit distri- and Libbey, 1956, Hotz, 1964, Ziessink, 1971. Most laterites vary from relatively pure iron-rich types to more aluminous varieties which may contain enough aluminum to form bauxite deposits. Laterites are rarely mined for their iron content, but the aluminum in bauxites is the only major source yet exploited for this crucial metal. The term ferruginous bauxite was coined by Libbey and others (1945) to describe deposits high in both iron and aluminum which occur in western Oregon and Washington.Similar deposits have since been found at other locations (Patterson, 1971). Hook (1976) and Jackson (1971Jackson ( , 1974 arbitrarily set a 10 percent free silica limit on the term 'ore grade' ferruginous bauxite. Since none of the ferruginous bauxite in Oregon or Washington has been shown to be economically exploitable, the term ore is not used in this paper. This is the 'blanket' theory for ferruginous bauxite formation. The second hypothesis is that the ferruginous bauxite deposits were locally developed in response to some variable such as microclimate, drainage (Hook, 1976) or parent rock composition (Hoffman, 1981) which was for some reason different in the areas where ferruginous bauxite developed. Pisolitic Zone 1.Sm I>Irregularly ahaped 9ibbsite and Nodul., Zone (Gordon and others, 1958, Grubb, 1979, Patterson, 1971. The characteristics of these zones may change, but their general nature is quite similar from one deposit to the next.The uppermost zone of Columbia County ferruginous 5 bauxite deposits is invariably pisolitic (Libbey and others, 1945, Wilkinson and others, 1946, Jackson, 1974. Pisolites are of various types, and include clayrich varieties, gibbsitic varieties and limonitic (highiron varieties (Libbey and others, 1945, Livingston, 1966). High-iron pisolites appear to be the most common type in surface outcrops in Columbia County. The pisolitic ferruginous bauxite typically grades downward into 6 the nodular zone. The nodular zone contains two types of nodules, one of which is gibbsitic and the other limonitic, in a matrix of orange to brown ferruginous bauxite (Jackson, 1971). The gibbsite nodules are pink or gray, normally quite angular and rare1ly more than 5 cm in longest dimension (Jackson, 1971). The limonitic nodules are commonly of similar size, but tend to be shades of brown and orange. The underlying zone of fine-grained, brown earthy ferruginous bauxite with its hard, angular grains of iron and aluminum oxides and hydroxides is typically lower in Sio 2 than either of the overlying zones, but it has a strong petrographic resemblance to the mat...

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Genesis of bauxite deposits in the lower Amazon Basin and Guianas coastal plain

Cited by 37 publications

References 0 publications

Cobertura Bauxítica E Origem Do Caulim Do Morro Do Felipe, Baixo Rio Jari, Estado Do Amapá

Cobertura Bauxítica E Origem Do Caulim Do Morro Do Felipe, Baixo Rio Jari, Estado Do Amapá

Solos Gerados a Partir Do Intemperismo De Crostas Lateríticas Sílico-Ferruginosas

Formation and zonation of ferruginous bauxite deposits of the Chapman quadrangle, Oregon

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