Geometry of propagating continental rifts

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, is described. The rifts become asymmetric as a consequence of the role played by low-angle normal faults in the overall rift geometry. Geometries which may be responsible for the detachments that are thought to underlie rifts are discussed.