Geometry of propagating continental rifts

Abstract

Reconstruction of past plate configurations through palinspastic restoration of continental margins1-4 requires a detailed knowledge of the geometries of horizontal continental extension. Extension is often restricted to discrete, linear zones termed rifts5,6, and rift models that invoke propagating vertical dykes and cracks7-10 are useful for assessing the relative significance and timing of uplift, subsidence and extension in the tectonic evolution of rift basins. However, many models do not adequately account for the observed asymmetry of rifts. I describe here the general three-dimensional character of young and aborted continental rifts, which can be used to derive a structural model for the propagation of rifts in continental lithosphere. The rifts become asymmetric as a consequence of the role played by low-angle normal faults in the overall rift geometry. © 1985 Nature Publishing Group.