Neoproterozoic arc–continent and continent–continent collision in the Northern Brasília Orogen: insights from U–Pb detrital zircon provenance and metamorphic modelling

In the Northern Brasília Orogen, formed during the assembly of West Gondwana, delineating medium- to high-grade lithostratigraphic units affected by intense deformation remains challenging. The stratigraphic correlations and tectonic evolution of units located between the Mara Rosa Magmatic Arc and intracontinental rift deposits are still not fully understood. This study integrates field data, U–Pb detrital zircon provenance analysis and metamorphic modelling to constrain the tectonic setting and evolution of the Uruaçu Complex and the surrounding Serra da Mesa Group. U–Pb detrital zircon data from the Serra da Mesa Group suggest deposition in three basins: (1) a Paleo-Mesoproterozoic intracontinental extensional basin; (2) a Neoproterozoic arc-related basin along the margins of the Mara Rosa Magmatic Arc, with minor contributions from the São Francisco Craton, correlative with the Uruaçu Complex; and (3) a syn-orogenic basin formed during arc–continent collision. Pseudosection modelling of the Uruaçu Complex constrains peak metamorphic conditions at ∼0.7 GPa and 700°C. This unit thrusts over the Serra da Mesa Group which records a clockwise P–T path from 0.43 GPa and 547°C to 0.59 GPa and 616°C. This metamorphic inversion is the result of the Neoproterozoic continent–continent collision between the Amazonian and São Francisco palaeocontinents. Normal structures provide preliminary evidence for post-collisional extension in the Northern Brasília Orogen.