Mineral weathering in acid saprolites from subtropical, southern Brazil

Clemente, Celso Augusto; Azevedo, Antônio Carlos de

doi:10.1590/s0103-90162007000600007

Cited by 24 publications

(16 citation statements)

References 11 publications

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“…The soils in the river basins with drainage to the studied coastal plains do not usually have smectite in their mineralogical composition (Sakai and Lepsch, 1984;Rossi, 1999;Furian et al, 2002;Ishida, 2005;Clemente and Azevedo, 2007). Therefore, the nontronite present in the soils studied was either inherited from continental platform marine sediments, is an authigenic mineral, or a combination of both.…”

Section: Discussionmentioning

confidence: 98%

Smectite in mangrove soils of the State of São Paulo, Brazil

Souza-Júnior

Vidal‐Torrado²,

García‐González

et al. 2010

Sci. agric. (Piracicaba, Braz.)

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Smectitic clay minerals are frequently identified in mangrove soils, but there is little information about their types and origins. Besides their importance in the agronomical and geotechnical areas, smectites play an important environmental role by adsorbing nutrients, organic pollutants and heavy metals. Smectites found in mangrove soils can be of marine or continental detrital origin, or of neoformation origin. Thus, the objective of this study was to identify the types of smectites present in the State of São Paulo mangrove soils (Brazil), and to relate them to their possible origins. Soil samples were taken in five mangroves along the State of Sao Paulo State coast line. The mineral composition of the clay fraction was identified by X-ray Diffractometry (XRD) applying the Greene-Kelly test and by Fourier transform infrared spectroscopy (FTIR). Highlighting the peaks in the 3,560 cm-1 band and in the region near 798 and 820 cm-1, there was a predominance of nontronite in the soil at the Sítio Grande River, Pai Matos Island, Caranguejo Island and Itapanhaú River mangroves, and possibly a lower concentration of ferric montmorillonite in the Escuro River mangrove. Since the continental sediments in these environments are very poor in smectite, the origin of these minerals in the mangrove soils studied is related to sedimentation left by past marine transgressions, to neoformation processes, or yet to a combination of both origins.

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Section: Discussionmentioning

confidence: 98%

Smectite in mangrove soils of the State of São Paulo, Brazil

Souza-Júnior

Vidal‐Torrado²,

García‐González

et al. 2010

Sci. agric. (Piracicaba, Braz.)

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“…in region II, from 450 to 743 g kg -1 in region III, and from 489 to 613 g kg -1 in region IV, indicating that the essential minerals, such as plagioclase, pyroxene, and alkali feldspar of the rhyodacites (Clemente and Azevedo, 2007) and plagioclase, pyroxene, and olivine of basalts (Corrêa, 2003) were completely weathered, forming clay minerals and pedogenic oxides.…”

Section: Characterization and Distribution Of Soils In The Regionsmentioning

confidence: 99%

Genesis and Classification of Soils from Subtropical Mountain Regions of Southern Brazil

Dortzbach

Pereira

Anjos

et al. 2016

Rev. Bras. Ciênc. Solo

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Soils formed in high mountainous regions in southern Brazil are characterized by great accumulation of organic matter (OM) in the surface horizons and variation in the degree of development. We hypothesized that soil properties and genesis are influenced by the interaction of parent materials and climate factors, which differ depending on the location along the altitudinal gradient. The goal of this study was to characterize and classify the soil, evaluate soil distribution, and determine the interactive effects of soil-forming factors in the subtropical mountain regions in Santa Catarina state. Soil samples were collected in areas known for wine production, for a total of 38 modal profiles. Based on morphological, physical, and chemical properties, soils were evaluated for pedogenesis and classified according to the Brazilian System of Soil Classification, with equivalent classes in the World Reference Basis (WRB). The results indicated that pedogenesis was strongly influenced by the parent material, weather, and relief. In the areas where basic effusive rocks (basalt) were observed, there was formation of extensive areas of clayey soils with reddish color and higher iron oxide contents. There was a predominance of Nitossolos Vermelhos and Háplicos (Nitisols), Latossolos Vermelhos (Ferralsols), and Cambissolos Háplicos (Cambisols), highlighting the pedogenetic processes of eluviation, illuviation of clay, and latosolization in conditions of year-long, large-volume, well-distributed rainfall and stability of land forms. In areas with acid effusive rocks (rhyodacites), medial or clayey soils were observed with lower iron oxide content, invariably acidic, and with low base content. For these soils, relief promoted substantial removal of material, resulting in intense rejuvenation, with a predominance of Cambissolos Háplicos (Cambisols) and lesser occurrence of Nitossolos Brunos (Nitisols) and Neossolos Litólicos (Leptosols). Soils formed from sedimentary rocks also tended to be more acidic, but with higher sand content, and the soils identified were Cambissolos Háplicos and Húmicos (Cambisols). Cluster analysis separated the soil profiles into three groups: the first and largest was formed by profiles originating from sedimentary rocks and rhyodacites; the second, smaller group was formed by four profiles in the Água Doce region (acidic rocks); and the third was formed by profiles derived from basalt. Discriminant analysis was effective in grouping soil classes. Thus, the study highlighted the importance of geology in the formation of soils in this landscape associated with climate and relief.

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“…Os caminhos do intemperismo das rochas ácidas da região são pouco compreendidos. Sabe-se, até o momento, que nos riodacitos do membro Chapecó as condições ambientaissobretudo as climáticas atuais -são responsáveis pela alteroplasmação dos fenocristais de plagioclásio, gerando minerais secundários por três caminhos: a) diretamente gibbsita, b) gel amorfo para caolinita e posteriormente para gibbsita e c) diretamente gibbsita e goetita (CLEMENTE; AZEVEDO, 2007). Nesta sequência percebe-se que a alitização é o processo predominante.…”

Section: Mineralogia Das Argilas Da Fração Finaunclassified

Contribuição para a reconstrução de paleoperfis de alteração no planalto de Palmas/Água doce - Sul do Brasil

2015

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O presente artigo visa reconstruir paleoperfis de alteração a partir dos sedimentos de depósito de articulação encosta/calha fluvial no Planalto de Palmas/Água Doce durante os 41.000 anos AP. Foram empregadas análises granulométricas, químicas e mineralógicas da fração argila em seção previamente caracterizada. Reconheceram-se quatro momentos distintos de intemperismo na área de estudo: a) antes de 41.000 anos AP se desenvolveram dois momentos ainda não identificados, um de monossialitização e outro de alitização; b) entre 41.000 a 25.000 anos AP registra-se a passagem para acidólise; c) entre 25.000 e 11.000 anos AP houve mudança de processo retornando a hidrólise; e d) nos últimos 11.000 anos, os materiais mantiveram o registro geoquímico das fases anteriores.

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Mineral weathering in acid saprolites from subtropical, southern Brazil

Cited by 24 publications

References 11 publications

Smectite in mangrove soils of the State of São Paulo, Brazil

Smectite in mangrove soils of the State of São Paulo, Brazil

Genesis and Classification of Soils from Subtropical Mountain Regions of Southern Brazil

Contribuição para a reconstrução de paleoperfis de alteração no planalto de Palmas/Água doce - Sul do Brasil

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