Produção Nacional
Diagênese de arenitos da Formação Tatuí no estado de São Paulo
2010; Sociedade Brasileira de Geologia; Volume: 40; Issue: 1 Linguagem: Inglês
10.25249/0375-7536.20104016879
ISSN2177-4382
AutoresNara Lúcia Barbosa-Gimenez, Maria Rita Caetano-Chang,
Tópico(s)Geological formations and processes
ResumoTatuí Formation represents the Permian post-glacial sedimentary rocks of the Paraná Basin, in São Paulo state. The unit is correlated to Palermo and Rio Bonito formations (Guatá Group) found in southern states of Paraná, Santa Catarina and Rio Grande do Sul. Petrologic analysis of Tatuí Formation sandstones using optical microscopy and catodoluminescence provided the understanding of their diagenetic evolution. These studies were carried on samples from well cores and outcrops in São Paulo State. During the eogenetic regime the sediments undergone processes such as replacement of bioclasts (calcareous shells of bivalves), unstable minerals dissolution and cement precipitation of microcrystalline calcite, pirite, K-feldspar, and Fe-oxides. Mesogenetic regime was characterized by mechanical compaction, quartz and plagioclase overgrowths, poikilotopic and mosaic calcite cementation, dolomite through ankerite cementation, followed by calcite and feldspar dissolution, precipitation of kaolinite and late calcite, albitization of feldspars, precipitation of zeolite, anhydrite, anatase and silica. Sandstones submitted to telodiagenesis show high ferruginous and kaolinite cement, feldspar dissolution and absence of calcite cement.
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