Ductile Extrusion Triggered by Continental Collision in NE Brazil

ABSTRACT The Borborema Province in northeastern Brazil hosts one of the world's largest strike‐slip shear zone networks, active during the late Neoproterozoic assembly of West Gondwana. Whether these shear zones initiated during active continental collision or as a post‐orogenic response to far‐field stresses remains debated. Here, we integrate monazite petrochronology and phase equilibrium modelling of metapelites from the South Borborema Orogen (SBO) to constrain the timing and conditions of continental collision. Our results indicate that foreland‐directed nappe stacking in the external zone occurred at 620–590 Ma, whereas peak metamorphism in the internal zone was attained at ~580 Ma, coeval with the onset of strike‐slip shearing in the overriding plate. We interpret these results to indicate that ductile extrusion in the Borborema Province was triggered by ongoing continental collision, analogous to modern collision–extrusion systems.