THE EDORAS BANK MARGIN - CONTINENTAL BREAK-UP IN THE PRESENCE OF A MANTLE PLUME

Edoras Bank lies on the eastern continental margin of the North Atlantic about 900km south of the present-day Iceland plume. We studied the continent-ocean transition of the rifted margin using normal-incidence and wide-angle seismic reflection data. Seaward dipping reflectors are well-developed over much of the margin and are underlain by a high velocity (7.3-7.5 km s(-1)) lower crust. This is interpreted as either igneous underplating or as existing crust heavily intruded at the time of break-up by melts with high MgO contents and suggests that the thermal anomaly associated with the Iceland plume was well-developed in this area at the time of break-up.