Geologia e litogeoquímica da formação serra geral nos estados de mato grosso e mato grosso do sul

The basalts of the Formação Serra Geral in Parana Basin in the Mato Grosso do Sul and Mato Grosso states cover an area of 180,000 km2. They rest on the Botucatu sandstones and they are recovered by the sedimentary rocks of Bauru and Caiuá Groups. The mineralogical composition of these rocks are plag...

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Bibliographic Details
Authors: Machado, Fábio Braz [UNESP], Nardy, Antonio José Ranalli [UNESP], Rocha Junior, Eduardo Reis Viana, Marques, Leila Soares, Oliveira, Marcos Aurélio Farias de [UNESP]
Format: article
Status:Published version
Publication Date:2009
Country:Brasil
Institution:Universidade Estadual Paulista (UNESP)
Repository:Repositório Institucional da UNESP
Language:Portuguese
OAI Identifier:oai:repositorio.unesp.br:11449/71388
Online Access:http://www.periodicos.rc.biblioteca.unesp.br/index.php/geociencias/article/view/3985
http://hdl.handle.net/11449/71388
Access Level:Open access
Keyword:basalt
chemical composition
clinopyroxene
lava flow
mantle source
mineralogy
partial melting
plagioclase
sandstone
sedimentary rock
Parana Basin
Eugenia uniflora
Description
Summary:The basalts of the Formação Serra Geral in Parana Basin in the Mato Grosso do Sul and Mato Grosso states cover an area of 180,000 km2. They rest on the Botucatu sandstones and they are recovered by the sedimentary rocks of Bauru and Caiuá Groups. The mineralogical composition of these rocks are plagioclase (40%-55%), clinopyroxenes (19%-40%; augite and pigeonite), opaque minerals (2%-10%; magnetite and ilmenite) and olivine (1.5%). Geochemical data show two different types of basalts, named ATi-Pitanga (2.6% < TiO2 < 4.2%; 396 ppm < Sr < 438 ppm) and BTi-Ribeira (1.7% TiO2 <2.4%, 246 ppm < Sr < 286 ppm). In general, ATi-Pitanga have gently higher La/Yb(n) (6,1 ± 1,5ppm) than those BTi-Ribeira (5.6 ± 1,7ppm). The geochemical differences between ATi-Pitanga and BTi-Ribeira probably are related to different degrees of partial melt of a same mantle source, or to different mantle sources. The field relations show that BTi-Ribeira is displaced towards the north-western margin of the Paraná Basin and the thickness of lava flows increases towards the Paraná Graben, suggesting that ATi-Pitaga overlies BTi-Ribeira.

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