Seismic images of crust beneath Iceland contribute to long-standing debate



Since the 1970s there has been an ongoing debate about whether the crust beneath Iceland is relatively thin (<15 km) and hot, or thicker (>20 km) and cooler. New results from the Faeroe-Iceland Ridge Experiment (FIRE) conducted in the summer of 1994 suggest that it is thicker and cooler.

This major land-sea study investigated the crust generated where the North Atlantic spreading center intersects the Iceland mantle plume and mapped the transition from thickened oceanic crust to the continental fragment on which the Faeroe Islands sit. Seismic techniques were used to obtain a 600-km profile of the area (Figure 1). Preliminary results suggest that a 20-km-thick crust is being generated beneath the northern Neovolcanic Zone of Iceland, with a high-level crustal magma chamber beneath Krafla. In northeast Iceland, the igneous crust is considerably thicker, reaching 35 km, while along the Faeroe-Iceland Ridge it varies between 25–30 km.