Geological and structural markers of the eastern Borborema Province based on a geotransect covering the Paraíba, Pernambuco, Alagoas and Sergipe states, northeastern Brazil

Abstract

This study comprises a field investigation of a NE-SW geological transect along the Eastern Borborema Province in NE Brazil. The transect covered distinct geological domains that differ in a number of as-pects, being bounded by shear zones. The oldest rocks are found in the Alto Moxotó and part of the Rio Capibaribe terranes in the Transversal Zone Domain as well as in the Belém do São Francisco Complex and Simão Dias Dome in the Sergipano Fold Belt. Early to late Neoproterozoic units are found in all do-mains, but are strongly restricted within the Alto Moxotó Terrane that is characterized by the oldest tecto-nic fabric (Dn). Dn+1 markers are mostly observed on the Sergipano Fold Belt, thrusting Neoproterozoic supracrustal rocks towards the São Francisco Craton, evidence an ancient active continental margin. Later strike-slip markers represent the Dn+2 phase and are materialized on the E-W Pernambuco Lineament and the Congo-Cruzeiro do Nordeste Shear Zone that separates the Rio Capibaribe and Alto Moxotó terranes of the Transversal Zone Domain. Lastly, Dn+3 is related to brittle structures such as joints, shear fractures, and veins as well as post-kinematic pegmatite filling-up, that cross-cut all of the studied units, being also attributed to reactivation of the older structures during the Cambrian.