Gradiente tectônico da porção sudeste de Ibaretama e adjacências, província Borborema, Ceará

Abstract

The structural geological mapping has characterized the degree of deformation with the application of the Flinn's diagram. The study is inserted in Ibaretama, Ibicuitinga, Morada Nova and Quixadá in Ceará, in the context Precambrian of the Borborema Province. The area has 100km 2, mapped on 1:50,000 scale, which to be in the Rio Grande do Norte and Ceará Central Domains. Granitic gneisses, biotite gneisses ortho and paraderivados with manganese occurrences represent the Jaguaretama Complex and Acopiara Unit, of the Rio Grande do Norte Domain. The Orós Belt consists of quartzite sillimanite intercalated with aluminous schists. Canindé Unit, of the Ceará Central Domain has biotite garnet gneisses, with portions migmatized, paraderivados. The Brasilianos granites are syenogranites with or without mylonitization. The metamorphism in the area, occurred progressively in the amphibolite facies, which formed the mineral association of zone grenade in the Jaguaretama Complex, Acopiara and Canindé Units and sillimanite zone in the Orós Belt, the gravite was the only unit unaffected by this metamorphism. Also occurred phase of low grade, of the greenschist facies, with minerais such as chlorite and muscovite. The Brasiliano orogeny generated the dextral transcurrent Senador Pompeu and Orós shear zones, that intersect the area and currently have northeast trend of foliation (Sn +1). Laboratory Analysis of the samples expressed leveis different of deformation. In ten samples oriented, based on the Flinn diagram, in general, resulted in flattening deformation, as obtained in six samples distributed outside the intersection of the two shear zones. Note that the constrictive response printed rocks, found in the shear zone generated simple movement between the blocks.