Revisiting the Dom Feliciano Belt and surrounding areas – An integrated geophysical and isotope geology approach

Abstract

The reconstruction of orogenic terranes across conjugate margins separated by oceanic formation requires the integration of complementary geological records from both regions. A major challenge lies in the loss of geological evidence following orogenic events, particularly processes associated with later continental break-up, such as those in southwestern Gondwana. In southeastern Brazil, Uruguay, and southwestern Africa, these records include Archean to Mesoproterozoic terranes and Pan-African-Brasiliano mobile belts. Following the amalgamation of the Gondwana supercontinent, these terranes underwent multiple phases of uplift, subsidence, and erosion, making their paleogeographic reconstruction more complex. To overcome these complexities, various datasets, including gamma-ray spectrometry, magnetic and gravity surveys, geological mapping, and UPb geochronology, were integrated. Our analysis reveals distinct geophysical domains and major lineaments defined by magnetic, gravimetric, and gamma-ray anomalies, providing new insights into the western Gondwana structural framework. The study highlights the collision between the Rio de la Plata Craton and the Congo and Kalahari cratons, characterized by thrust-and-fold belts and strike-slip systems. Distinct terranes are well-constrained, including the Rio de la Plata Craton, the São Gabriel magmatic arc, the Tijucas fold-and-thrust belt, and Ediacaran to Eopaleozoic terranes (Encruzilhada, Pelotas, and Punta del Este arcs), along with late to post-orogenic basins. Our refined mapping of terrane boundaries and shear zones enhances our understanding of tectonic evolution and supports correlations between terranes now separated by the South Atlantic. These findings improve interpretations of southwestern Gondwana's tectonostratigraphic architecture and its cratonic and orogenic assembly processes.