Oblique rift systems: 3D numerical lithospheric-scale experiments from rift to breakup

Rifting involves complex normal fault systems that are controlled by extension direction, reactivation of pre-rift structures, sedimentation, and dyke dynamics. The relative impact of these factors on the observed fault pattern, however, is difficult to deduce from field-based studies alone. 

This study provides insight in crustal stress patterns and fault orientations by employing a laterally homogeneous, 3D rift setup with constant extension velocity. The presented numerical forward experiments cover the whole spectrum of oblique extension. They are conducted using an elasto-visco-plastic finite element model and involve crustal and mantle layers accounting for self-consistent necking of the lithosphere.

Despite recent advances, 3D numerical experiments still require relatively coarse resolution so that individual faults are poorly resolved. This issue is addressed by applying a post-processing method that identifies the stress regime and preferred fault azimuth at each surface element.

This figure illustrates the setup and results for a rift experiment with 45° obliquity. The fault orientations change in a characteristic manner during rift inception, maturation, and break-up .

Cite as:

Brune, S., 2014. Evolution of stress and fault patterns in oblique rift systems: 3-D numerical lithospheric-scale experiments from rift to breakup. Geochem. Geophys. Geosyst. 15, 3392–3415. doi:10.1002/2014GC005446

Download and Resources:

Link to Paper | Link to Supplementary Figures | Model evolution pdfs: , 15°, 30°, 45°, 60°, 75°, 90°