Notas sobre a formação de gibsita em solos de Viçosa

Autores

  • Onofre C B Pinto Universidade Federal de Viçosa

Palavras-chave:

origem gibsita, intemperismo solos, caolinita plagioclásios, drenagem lixiviação, difração raios

Resumo

Four soil profiles from Viçosa, Minas Gerais, Brazil, were studied. A strongly weathered biotite-feldspar gneiss (plasioclase) formed the parent material on which these soils developed. The minerals present in each of the profiles were identified by x-ray technique. Kaolinite and quartz were found to be present in large amounts; gibbsite and iron oxides, in smaller amounts.

Kaolinite was found in all soil fractions; quartz was found in the sand and silt fractions; and gibbsite, in the silt and clay fractions. Kaolinite was found as pseudomorphs after mica in considerable amounts in the sand silt fractions.

No avidence was found for the formation of gibbsite by wathering from the plagioclase component of the parent rock. The presence of gibbsite in the silt-sized fraction sugests that silt-sized gibbsite may be formed through desilication of the pseudomorphs of kaolinite.

Referências

ALEXANDER, L.T., HENDRICKS, S.B & FAUST, G.T. Occurence of gibbsite in some soil-forming material. Soil Sei.Soc.Amer Proc., Madison, 6:52-57. 1942.

BATES, T.F. Halloysite and gibbsite formation in Hawaii. Clays and Clay Minerals. New York, 11: 315-328. 1962.

GARDNER, L.R. A chemical model for the origin of gibbsite from kaolinite. Amer. Min., Lancaster, 55:1380-1939.1970.

JACKSON, M.L. Soil chemical analysis, advanced course. Ma- dison. Dept. of Soil Science, University of Wisconsin, 1956. 894 p.

JACKSON, M.L. Chemical composition of soils. In: BEAR, F.E, ed., Chemistry of the soil. New York, Reinolds Publishing Corporation, 1964, pp. 71-141.

KELLER, W.D. Principles of chemical weathering. Columbia, Missouri, Lucas Brothers Publishers, 1lp. 1968.

PINTO, 0.C.B., YAHNER, J.E., & ROTH, C.B. Natureza e formação de caolinita em forma de pseudomica, em solos de Viçosa, Minas Gerais. Experientiae, Viçosa, 13: 383-421. 1972.

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Publicado

1972-08-30

Como Citar

C B Pinto , O. (1972). Notas sobre a formação de gibsita em solos de Viçosa . Revista Ceres, 19(104), 299–305. Recuperado de https://ojs.ceres.ufv.br/ceres/article/view/6658

Edição

v. 19 n. 104 (1972)

Seção

ARTICLE

Licença

Creative Commons License
Este trabalho está licenciado sob uma licença Creative Commons Attribution 4.0 International License.

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