Garces, Miguel; Gee, Jeffrey S. (2007): Paleomagnetic evidence of large footwall rotations associated with low-angle faults at the Mid-Atlantic Ridge. Geological Society of America (GSA), Boulder, CO, United States, Geology (Boulder), 35 (3), 279-282, georefid:2007-029098

Exposures of gabbros and mantle-derived peridotites at slow-spreading oceanic ridges have been attributed to extension on long-lived, low-angle detachment faults, similar to those described in continental metamorphic core complexes. In continental settings, such detachments have been interpreted as having originated and remained active at shallow dips. Alternatively, currently shallow dipping fault surfaces may have originated at moderate to steep dips and been flattened by subsequent flexure and isostatic uplift. While the latter interpretation would be more consistent with Andersonian faulting theory, it predicts large footwall tilts that have not been observed in continental detachment faults. Here we use the magnetization of oceanic gabbro and peridotite samples exposed near the Fifteen-Twenty Fracture Zone on the Mid-Atlantic Ridge to demonstrate that substantial footwall rotations have occurred. Widespread rotations ranging from 50 degrees to 80 degrees indicate that original fault orientations dipped steeply toward the spreading axis.
West: -47.3000 East: -44.3000 North: 16.0000 South: 14.3000
Expedition: 209
Site: 209-1270
Site: 209-1271
Site: 209-1272
Site: 209-1274
Site: 209-1275
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