Exchange properties and mineralogy of some soils derived from lavas of lower old red sandstone (devonian) age. II. mineralogy

Wilson, Matthew

doi:10.1016/0016-7061(76)90056-2

Cited by 11 publications

(4 citation statements)

References 19 publications

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“…These reactions indicate an interstratified swelling chlorite-smectite of a trioctahedral nature since its 060 spacing occurs at 1-54A. Similar mineral occurs widely in altered lavas in Scotland (Wilson 1976). It is a magnesium-rich mineral although in the present case the distinctive brown colour indicates a high iron content (15% Fe 2 O 3 by X-ray fluorescence analysis).…”

Section: The Rockmentioning

confidence: 50%

Weathering of a Basalt by Pertusaria Corallina

Jones¹,

Wilson²,

Tait³

1980

The Lichenologist

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The weathering phenomena resulting from the encrustation of basalt by Pertusaria corallina have been studied by scanning electron microscopy and a variety of other techniques. The rock consists largely of plagioclase felspar (labradorite) and ferromagnesian minerals, the latter often being replaced by hydrothermally formed ferruginous clay minerals. Lichen weathering results in the extensive etching of the primary rock-forming minerals, particularly labradorite, and in the degradation of the clay minerals to yield a thin ochreous crust of poorly-ordered ferruginous (ferrihydrite) and alumino-silicate materials. These changes are brought about principally by the oxalic acid secreted by the mycobiont, a conclusion supported by observations following experimental mineral alteration.

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Section: The Rockmentioning

confidence: 50%

Weathering of a Basalt by Pertusaria Corallina

Jones¹,

Wilson²,

Tait³

1980

The Lichenologist

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“…6 ). Although this complex crystal structure has been evoked in the past in both experimental alteration experiments and for natural soil samples 27 28 30 31 32 33 34 46 , the structural quantification of these two types of layers has been performed only very recently 25 26 . Moreover, such a quantitative structural model based on interstratification of layers has not yet been used to explain the mobility of Cs + associated with clay minerals.…”

Section: Discussionmentioning

confidence: 99%

Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

Dzene

Ferrage

Viennet

et al. 2017

Sci Rep

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Radioactive caesium pollution resulting from Fukushima Dai-ichi and Chernobyl nuclear plant accidents involves strong interactions between Cs+ and clays, especially vermiculite-type minerals. In acidic soil environments, such as in Fukushima area, vermiculite is subjected to weathering processes, resulting in aluminization. The crystal structure of aluminized clays and its implications for Cs + mobility in soils remain poorly understood due to the mixture of these minerals with other clays and organic matter. We performed acidic weathering of a vermiculite to mimic the aluminization process in soils. Combination of structure analysis and Cs + extractability measurements show that the increase of aluminization is accompanied by an increase in Cs + mobility. Crystal structure model for aluminized vermiculite is based on the interstratification of unaltered vermiculite layers and aluminized layers within the same particle. Cs + in vermiculite layers is poorly mobile, while the extractability of Cs + is greatly enhanced in aluminized layers. The overall reactivity of the weathered clay (cation exchange capacity, Cs + mobility) is then governed by the relative abundance of the two types of layers. The proposed layer model for aluminized vermiculite with two coexisting populations of caesium is of prime importance for predicting the fate of caesium in contaminated soil environments.Existing studies devoted to the fate of radioactive caesium in polluted soil environments due to nuclear plant accidents systematically suggest that strong interactions occur between this pollutant and clay minerals, especially vermiculite-type minerals [1][2][3][4][5][6][7][8][9][10] . The layered structure of vermiculite involves an octahedral sheet sandwiched between two tetrahedral sheets. Isomorphic substitutions by less charged cations in tetrahedral sheets induce a permanent negative charge. This charge is compensated by the presence of exchangeable interlayer cations, which produces the high cation exchange capacity (CEC) values of vermiculites and their strong reactivity in cation adsorption/desorption processes.In the Fukushima area, Cs + is preferentially adsorbed in vermiculite-type minerals derived from the weathering of micaceous minerals 11,12 . However, in acidic soil environments, such as those encountered in the Fukushima area, aluminium is released into solution by the partial dissolution of vermiculite or micaceous minerals and is then commonly adsorbed again and partially hydroxylated in the interlayer space of the mineral 13 . This aluminization process in turn strongly impacts the reactive properties of the vermiculite minerals by leading to a decrease in the CEC [14][15][16] . The effects of acidic weathering and the associated aluminization of vermiculite in soils on the interactions with Cs + remain poorly understood. Indeed, existing studies on this topic have either evoked an increase in Cs + selectivity 1,9,17,18 or a decrease in the amount of poorly mobile Cs 6,[19][20][21][22] . Interpretations have been syst...

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“…Segundo Wilson (1976) e Garcia-Romero et al (2005), a nontronita é uma esmectita rara nos solos, formada, preferencialmente, sob condições de hidrotermalismo em alguns tipos de materiais de origem. Reforçando a influência do material de origem na formação dos minerais 2:1, em serpentinito (rocha ultrabásica rica em Mg) podem ser encontradas esmectitas magnesianas (trioctaedrais), como a saponita (Pinto & Kämpf, 1997;Vidal-Torrado et al, 2006 …”

Section: Resultados E Discussão Identificação De Minerais 2:1unclassified

Métodos de concentração de minerais 2:1 secundários na fração argila visando sua identificação por difratometria de raios x

Melo

Mattos²,

Lima³

2009

Rev. Bras. Ciênc. Solo

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RESUMOAlém dos baixos teores normalmente encontrados na fração argila dos solos sob clima tropical e subtropical, o tamanho reduzido e a baixa cristalinidade dos minerais 2:1 secundários dificultam sua identificação por difratometria de raios X (DRX). Este estudo objetivou avaliar métodos químicos e físico de concentração de minerais 2:1 secundários na fração argila para facilitar a identificação por DRX, incluindo a natureza dos minerais quanto ao local de formação de cargas permanentes (lâmina tetraedral ou octaedral). Coletaram-se amostras de dois Cambissolos originados de argilito da Formação Guabirotuba na Bacia Sedimentar de Curitiba (PR): horizontes A, Bi, C1 (1,2 a 1,5 m), C2 (2,2 a 2,5 m), C3 (3,2 a 3,5 m) e C4 (4,2 a 4,5 m). Após remoção da matéria orgânica e dispersão da terra fina seca ao ar, a fração argila foi submetida a tratamentos sequenciais com ditionito-citratobicarbonato (DCB) (amostra desferrificada -remoção de óxidos de Fe pedogenéticos) e com soluções de NaOH a quente, em diferentes concentrações (0,5; 1,0; 1,5; 2,5; 3,5; 4,0; 4,5 e 5,0 mol L -1 ), para extração de gibbsita e caulinita, em diferentes graus. A fração argila desferrificada também foi submetida à separação física (centrifugação) em argila grossa (0,2 a 2 μ μ μ μ μm) e fina (< 0,2 μ μ μ μ μm). Foram realizados tratamentos auxiliares para identificar as espécies minerais 2:1 na fração argila: saturação com Mg e solvatação com etilenoglicol; saturação com K e secagem ao ar e aquecimento a 550 °C; e saturação com Li (teste de Greene-Kelly). Os resultados mostraram que o método clássico de extração da caulinita, com solução de NaOH 5,0 mol L -1 a quente, não deve ser aplicado para concentração de minerais 2:1 secundários, pois também removeu grande parte desses minerais. O tratamento com DCB e com solução de NaOH 3,5 mol L -1 possibilitou, com maior eficiência, a concentração e identificação de minerais 2:1 secundários por DRX nas amostras dos horizontes A, Bi e C1. Nas amostras tomadas em maiores profundidades (horizontes C2, C3 e C4), devido aos maiores teores desses minerais e ao menor tamanho dos cristais (argila fina), a solução menos concentrada de NaOH (1,5 mol L -1 ) foi mais eficiente para esse propósito. No horizonte A, os minerais 2:1 concentraram-se na fração argila grossa, compatível com o maior grau de

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Exchange properties and mineralogy of some soils derived from lavas of lower old red sandstone (devonian) age. II. mineralogy

Cited by 11 publications

References 19 publications

Weathering of a Basalt by Pertusaria Corallina

Weathering of a Basalt by Pertusaria Corallina

Crystal structure control of aluminized clay minerals on the mobility of caesium in contaminated soil environments

Métodos de concentração de minerais 2:1 secundários na fração argila visando sua identificação por difratometria de raios x

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