We visualize the flexural rotation of high-angle normal faults at the axis and their development into low-angle detachment surfaces of oceanic core complexes. In regions of extreme tectonic extension normal faults display large rotations and we use the visualizations to obtain a better understanding of how the rotations occur and thus, the kinematics of detachment faulting and core complex formation. The visualizations emphasize how flexural rotation of the footwall occurs immediately after the formation of a fault and is mostly complete by about 10 km from the axis, even on faults that are long-lived and have developed into core complexes. We use our visualizations to synthesize the seafloor topography of several well-known North Atlantic core complexes including those at 13N at the Mid-Atlantic Ridge, the Logachev massif at 15.75N, the TAG core complex at 26N, and the Kane megamullion at 24N. One of the results of these visualizations is that on the basis of the morphology alone it is difficult to distinguish whether the seafloor topography is generated by long-lived detachment faults or by multiple short-lived faults since each can produce the backtilts that are observed on the faults. Our visualizations also show that gabbro bodies drilled at the low-angle detachment surface of core complexes were probably emplaced near the base of the active detachment fault and rode passively with the upward flexing footwall to the seafloor.
AGU Fall Meeting Abstracts
- Pub Date:
- December 2007
- 3035 Midocean ridge processes;
- 3045 Seafloor morphology;
- and geophysics;
- 3075 Submarine tectonics and volcanism