Claudio de Morisson Valeriano

Abstract: Abstract Four main classes of tectonic entities may be considered for the Ribeira Belt and southwest African counterparts: (1) cratonic fragments older than 1.8 Ga and their passive margin successions, (2) reworked basement terranes with Mesoproterozoic and/or Neoproterozoic deformed cover, (3) magmatic arc associations, (4) terranes with Palaeoproterozoic basement and deformed Neoproterozoic back-arc successions. Based on comparative investigation, a tectonic model of polyphase amalgamation is proposed with c. 790 and 630–610 Ma major episodes of intra-oceanic and cordilleran arc magmatism along both sides of the Adamastor Ocean. Subsequent diachronous collision of the arc terranes and small plates followed at c. 630, 600, 580 and 530 Ma. The tectonic complexity reflects an accretionary evolution from Cryogenian to Cambrian times. The São Francisco–Congo and Angola palaeo-continents did probably not behave as one consolidated block, but rather may have accommodated considerable convergence during the Brasiliano/Pan-African episodes. The final docking of Cabo Frio and Kalahari in the Cambrian was coeval with the arrival of Amazonia on the opposite side, resulting in lateral reactivation and displacement between the previously amalgamated pieces. The transition between the Cambrian and the Ordovician is marked by the extensional collapse of the metamorphic core zones of the orogens.

TL;DR: In this paper, the authors reported new U-Pb data from the southern sector of the Brasilia belt in order to provide temporal limits for the deposition and ages of provenance of sediments accumulated in passive margin successions around the south and southwestern margins of the Sao Francisco Craton, and date the orogenic events leading to the amalgamation of West Gondwana.

TL;DR: In this paper, the Mantiqueira complex represents a cordilleran-type active margin of the Archean paleocontinent, while the Juiz de Fora complex represents juvenile Paleoproterozoic material, probably developed within an oceanic setting (primitive arc or plateau?).

TL;DR: The Brasília Belt comprises terranes and thrust-sheets that were tectonically transported towards the western passive margin of the São Francisco-Congo palaeocontinent during an orogenic episode resulting from collision of the Paranapanema and Goiás blocks and the goiás magmatic arc against the Gondwana supercontinent at 0.64-0.61 Ga as discussed by the authors.