Modes of Propagation of Continental Breakup and Associated Oblique Rift Structures

V‐shaped oceanic propagators are widespread around the world. Their geometry combined with magnetic anomalies associated with their opening shows at the first order that ridge propagation in the third dimension occurs by pulses. In this study we use 3D thermomechanical numerical models to show how oblique kinematic boundary conditions control both the intracontinental rift development and the oceanic ridge propagation. To do so, we apply a shortening velocity boundary condition in the direction perpendicular to the extension for “strong” and “weak” crustal rheologies. Numerical model results highlight the finding that three ridge propagation modes can occur. For low out‐of‐plane velocities (12% to 15% of the extension rate), the ridge propagation is fast (>1.5 cm year−1) and straight. Higher shortening velocities (15% to 17%) lead to a ridge propagation by pulses alternating between fast propagation (~1.5 cm year−1) and stalling phases. Finally, for higher velocities (17% to 20%) a ridge jump propagation mode occurs, localizing a new spreading center between 100 and 200 km far from the initial ridge. We also show that ridge propagation phases are associated with dip‐slip‐dominated deformation, while stalling phases are dominated by strike‐slip deformation. These deformation regimes are marked by structure reorientation, while kinematic boundary conditions remain constant. We discuss these results in terms of plate tectonic reconstructions and regional geological studies. Key Points Oblique kinematic boundary conditions control both the intracontinental rift development and the oceanic ridge propagation The degree of obliquity leads to three ridge propagation modes: (1) fast, (2) by pulses, (3) by jumps The ridge propagation phases are associated with dip‐slip deformation, while stalling phases are dominated by strike‐slip deformation