Comparative study of the clay minerals of mesozoic and cenozoic rocks from the Central Depression of the Rio Grande do Sul state, Brazil
DOI:
https://doi.org/10.5902/2179460X24846Abstract
Analysis by x - ray diffraction permited to compare the nature of the clay minerals of Mesozoic rocks from the Central Depression of the Rio Grande do Sul State, Brazil (Rosário do sul Formation, Santa Maria Formation and Caturrira Member of the Botucatu Formation) with those of Cenozoic rocks (Tertiary? ) which partially cover the first ones. In the Mesozoic rocks predominates the montmorillonite, followed by illite and by mixed-layer I-M (10-14M). On other hand, in Cenozoic rocks there is a complete predomination of kaolinite, with litle percentage of ilite, mixed-layer I-M (10-14M) and montmorillonite. This difference helps in the distinction between the two sequences, in places where the litologies are not fully conclusive. The predominance of montmorillonite in the Mesozoic and kaolinite in the Cenozoic can be explained by climatic differences and / or by others causes. In the case of climatic differences, the Cenozoic would have been much more wet than the Mesozoic.
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BORTOLUZZI, C.A. Contribuição á geologia da região de Santa Maria, Rio Grande do Sul, Brasil. Pesquisas, Porto Alegre, UFRGS, (4): 7-86, 1974.
BROWN, G., Comp. The X Ray identification and structures of clay minerals. London, Mineralogical Society, 1972, 544p.
COLBERT, E.W. A Saurisshian Dinosaur From the Triassic of Brazil. Novitates, New York. 2405, p.39, 1970.
CORDANI, U,G. & VANDOROS, P. Basaltic rocks of the Paraná basin In: BIGARELLA, J.; BEKER, R.D.; PINTO,I.D. (Edit.) Problems in Brazilian Gondwana GeoLogy; Curitiba, p. 207-231, 1967.
CUNHA, R. O estuário do Guaíba. Características texturais, mineralógicas e morfológicas. Porto Alegre, Curso de Pôs-Graduação em Geociências, UFRGS, 1971, 51p. (Tese de Mestrado).
CUNHA, R. & FORMOSO, M.L.L. Argilominerais das rochas sedimentares da Bacia de Pelotas-Rio Grande do Sul. In: CONG. BRAS. DE GEOLOGIA, 309, 1978. Anais... Recife. SBG 3:1123-1134.
FANG, J.H. & BLOSS, F.D. X-Ray Difration Tables: Southern Illinois University Press. 1966.
GAMERMANN, N. Formação Rosário do Sul. Pesquisas, Porto Alegre, UFRGS (2): 5-25,.1973.
GORDON Jr., M. CLassification of the Gondwanic rocks of Parana, S. Catarina and Rio Grande do Sul. Notas Preliminarés e Estudos; Departamento Nacional de Produção Mineral, Div. de Geol. e Mineralogia; Rio de Janeiro. 38: 1-19, 1947.
HARDER, H. Clay mineral formation under lateritic conditions; Clay Minerals 12: 281-288, 1977.
MC.DOUGAL, I. & RUEGG, N.R. Potassium-argon dates on the Serra Geral Formation of South America. Geoch. Cosmoch. Acta; 30: 191-195, 1966.
MILLOT, C. Geologie des Argiles; Paris, Masson et Cie Editeurs, 1964, 499p.
RAMOS, A.M. & FORMOSO, M.L.L. Argilominerais das rochas sedimentares da Bacia do Paraná. Rio de Janeiro, Petrobrás, 1975, 77p. (Serie Ciência-Tecnica-Petrô1eo; secção: Exploração de Petróleo, 9).
SARTORI, P.L.P.; MACIEL FILHO, C; MENEGOTTO, E. Contribuição ao estudo das rochas vulcânicas da Bacia do Paraná na Região de Santa Maria, RS. Rev.Bras. de Geologia. São Paulo, 5 (3): 141-159, 1975.
VEIGA, P. Estudo dos arenitos "intertrapps" da Formação Serra Geral na região de Santa Maria, RS. Porto Alegre, Curso de Pôs-Graduação em Geociências, UFRGS, 1973, 88p. (Tese de Mestrado).
VILLWOCK, J.A. Aspecto da sedimentação na região nordeste da Lagoa dos Patos: Lagoa do Casamento e Saco do Cocuruto-RS-Brasil Porto Alegre, Curso de Pôs-Graduação em Geociências, UPRGS,1973, 88p. (Tese de Mestrado).
WHITE, I.C. Relatório Final da Comissão de Estudos das Minas de Carvão de Pedra do Brasil. Parte 1: Relatorfo sobre as ”Coal Messures" e rochas associadas do Sul do Brasil; Rio de Janeiro, Min. da Ind. Viação e Obras Públicas, 190B, 300p.
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