The geochemistry and origin of the Faeroe-Shetland sill complex

Summary Geochemical investigations of dolerite cores from four intrusions in the recently discovered Faeroe-Shetland sill complex have established that the sills are of transition (T) mid-ocean ridge basalt (MORB)-type composition. Some uncertainty surrounds the age of the complex, but there is no doubt that it is, at least in part, of Tertiary age. Comparisons with previously proposed models for the development of sill-sediment complexes during initial stages of seafloor spreading suggests that the Faeroe-Shetland sills may represent an intrusive episode associated with a spreading axis that eventually produced oceanic crust W of the Faeroes.