Propagating rift model for the V-shaped ridges south of Iceland

Abstract

We present new marine geophysical data which constrain the seafloor spreading history of the Reykjanes Ridge near Iceland and the origin of its flanking V-shaped topographic and gravity ridges. Contrary to the geometry assumed in pulsing plume models, the V-shaped ridges are not symmetric about the Reykjanes Ridge axis, and seafloor spreading has not been symmetric about a stable axis. Thus, existing models must at least be modified to include an additional asymmetry-producing mechanism; the best understood and documented such mechanism is rift propagation. One possibility is that plume pulses drive the propagators. However, rift propagation also produces V-shaped wakes with crustal thickness variations, suggesting the possibility that a pulsing Iceland plume might not be necessary to explain the Reykjanes V-shaped ridges, scarps, and troughs. Copyright 2010 by the American Geophysical Union.