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.