Geochronological review of the Precambrian in western Angola: links with Brazil

Abstract

In this study the main features of the Precambrian of western Angola are presented as a way of outlining the position of the Congo Craton and coastal Pan-African fold belts. These were separated from the São Francisco Craton and Atlantic Brasiliano fold belts in Brazil by the opening of the South Atlantic.The main events and cycles that affected the Precambrian lithostratigraphical units in western Angola, can be correlated with similar events in the northern part of the Congo Craton and in northwestern Namibia. Using these correlation and geochronological studies in the Luanda-Malanje region, two tectono-metamorphic events (the Lunda-Cuango-Malanje and the Malanje-Andulo events) are defined and several Precambrian lithostratigraphical units are reinterpreted.The margin of the Congo Craton in northwestern Angola (Luanda-Malanje region) is located between the Eburnian porphyroblastic gneisses and the Pan-African migmatites. The southern margin of this craton alternates between the Angolan and Brazilian coasts; then, after a brief incursion into Namibia, this limit runs northeast through southeast Angola until it meets the Lufilian Arc.