Detailed tectonic evolution of the Reykjanes Ridge during the past 15 Ma

Abstract

We present a new detailed tectonic model of the Reykjanes Ridge which examines the rift propagation hypothesis for the V-shaped ridges and its asymmetric lithospheric accretion. Four major southward rift propagations extend through our entire survey area and several additional small scale rift propagations are observed, including northward propagators. If plume pulses only drive southward propagators, then two different driving mechanisms for propagators must exist. There is a major difference in the crustal accretion asymmetry between the area immediately off the Iceland shelf and that farther south, both in rift propagation pattern and free air gravity lineations. Furthermore, we identify two small offset features coined ponsu-transforms, from which rift propagation is both initiated and stopped. The pattern of the V-shaped ridges on the Reykjanes Ridge is not symmetric about the Reykjanes Ridge and the V-shaped ridges are not linear continuous features. Our rift propagation model produces excellent fits to magnetic data and provides a self-consistent model for the evolution of the Reykjanes Ridge during the past 15 Ma. Copyright 2012 by the American Geophysical Union.