Contribuição à Geologia e à Geocronologia do Terreno Rio Capibaribe (TRC, Província Borborema)

Abstract

The Rio Capibaribe Terrane (TRC) was first referred for the south - southeast part of the Transversal Zone, central domain of the Borborema Province (minor part SE of Paraiba and NE of Pernambuco states). The attributed conventional boundaries for this terrane are major shear zones, the Congo - Cruzeiro do Nordeste (to the north and northwest) and Pernambuco lineament to the south. This terrane exhibits gneissic-migmatitic basement complexes of Paleoproterozoic age and Neoproterozoic fold belts of the Tonian (Cariris Velhos cycle) and the Cryogenian - Ediacaran (Brasiliano cycle). It is crosscuted by many intrusive rock assemblages of the Paleoproterozoic, Mesoproterozoic and Neoproterozoic ages, of different sources and tectonic natures (anorogenic plutonism, plutons related to shear zones, and magmatic arcs etc.), these last ones presenting calc-alkaline rock types of different compositional groups are emphasized. The TRC was known in small scales, mainly in geological maps of the mentioned states, in the beginnings of this century. There are these and other scientific papers of great importance about the geology of parts of this terrane; nevertheless, it was considered the less privileged of all terranes of the Borborema Province, in terms of geochronological evolution data, and this was the motivation for the development of this paper. Many geological sections were carried out pari passu to extensive bibliographical research, as well as with the implementation of new geochronological determinations, by different methods, as Mend (ca. 60), Rb-Sr (ca. 50) and U-Pb (ca. 8, TIMS + LA-ICPMS). During that time, the authors looked to be accounted with the development of new geological mapping (scales 1/ 100,000) projects, several sheets, along this terrane, that were performed by the CPRM (Brazilian Geological Survey). An interpretative synthesis of the geological and geochronological evolution is being proposed, with the sum and help of all these data, being valid only for the present instance, in order to explain the complex and rich crustal evolution of this terrane.