Contribution to the Geology and Geochronology of the Rio Capibaribe Terrane (TRC, Borborema Province)

Abstract

The Rio Capibaribe Terrane (TRC) was first referred for the south – southeast part of the Transversal Zone, central domainof the Borborema Province (minor part SE of Paraíba and NE of Pernambuco states). The attributed conventional boundariesfor this terrane are major shear zones, the Congo – Cruzeiro do Nordeste (to the north and northwest) and Pernambucolineament to the south. This terrane exhibits gneissic-migmatitic basement complexes of Paleoproterozoic age and Neoproterozoicfold belts of the Tonian (“Cariris Velhos” cycle) and the Cryogenian – Ediacaran (“Brasiliano” cycle). It is crosscutedby many intrusive rock assemblages of the Paleoproterozoic, Mesoproterozoic and Neoproterozoic ages, of differentsources and tectonic natures (anorogenic plutonism, plutons related to shear zones, and magmatic arcs etc.), these last onespresenting 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 scientificpapers of great importance about the geology of parts of this terrane; nevertheless, it was considered the less privileged ofall terranes of the Borborema Province, in terms of geochronological evolution data, and this was the motivation for thedevelopment of this paper. Many geological sections were carried out pari passu to extensive bibliographical research, aswell 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 geologicalmapping (scales 1/ 100,000) projects, several sheets, along this terrane, that were performed by the CPRM (Brazilian GeologicalSurvey). An interpretative synthesis of the geological and geochronological evolution is being proposed, with the sum and help of allthese data, being valid only for the present instance, in order to explain the complex and rich crustal evolution of this terrane.

Keywords

• Borborema Province
• Transversal Zone
• Paleoproterozic basement
• Mesoproterozoic intrusive rock units
• Neoproterozoic supracrustals
• Brasiliano Cycle.