Pernambuco-Alagoas, Riacho do Pontal, and Sergipano domains of the Borborema Province, Northeastern Brazil: a geological and geochronological synthesis

Abstract

In recent years, the number of works seeking to advance the geological and geotectonic knowledge of the Borborema Province has been increasing. However, in the context of the Southern Borborema Province there are few studies aimed at understanding its tectonic evolution in an integrated way. This work presents a review of the lithostratigraphic and geochronological data available for the Pernambuco-Alagoas, Riacho do Pontal and Faixa Sergipana Domains, located in the southern portion of the Borborema Province (Northeast Brazil), in addition to a discussion on the tectonic evolution model. The Southern Borborema Province fully encompasses the state of Alagoas and partially the states of Pernambuco, Sergipe, Bahia and Piauí, and is delimited to the north by the Pernambuco Lineament and to the south by the São Francisco Craton. The methodology involved bibliographical survey, geological cartography, geochronological compilation, creation of detrital zircon histograms for metasedimentary rocks (with unconformity below 10%) and magmatic “barcodes” for ortho-derived rocks and preparation of regional geological profiles. The tectonic evolution of the Southern Borborema Province began with the breakup of the Rodínia Supercontinent (1000 Ma) during the Cariris Velhos Cycle. The processes involved in the interaction of fragments descending from Rodinia are diachronic, in a broad scenario of accretions and collisions that resulted in the merger of Gondwana. The Pernambuco-Alagoas Block is considered a complex tectonic domain, which was affected by the Cariris Velhos (1000 – 950 Ma) and Brasiliana (740 - 570 Ma) orogenies (Caxito & Alkmim 2023), preserving remnants of Archean rocks (Riacho Seco Fragment) and proterozoic. The Riacho do Pontal Domain and the Faixa Sergipana Domain are part of a large folding system formed from the collision of the Pernambuco-Alagoas Domain with the São Francisco Craton, in a tangential deformation, vergent towards the craton, during the Brasiliana Orogeny. From the ages of the syncollisional granites we can infer that the orogenic event that gave rise to the aforementioned folded bands occurred at very close time intervals, presenting a slight diachronism. The article presents an integrated approach to tectonic evolution, however, the need for new studies is quite evident, with an emphasis on isotopic geology, geochronology, geochemistry and geological mapping that can contribute to the understanding of the processes involved in the formation of tectonic domains, their space-time relationships and their implications for the evolution of the Gondwana Continent.