Abstract

We present results from a combined normal incidence and wide-angle seismic survey of the Reykjanes Ridge at 61°40′N in the North Atlantic. The seismic data show that the crust is 8.4–10.0 km thick on the ridge axis. We attribute this thicker than normal oceanic crust to a high degree of melting caused by hot mantle from the Iceland plume beneath the speading centre. Layer 2A of the oceanic crust is significantly thicker at 0 Ma than in crust of age 4 Ma. Our results, combined with other seismic data from the North Atlantic, show that the crustal thickness decreases away from the plume centre to normal oceanic crustal thickness at a distance of approximately 1000 km.