Crustal structure of the Antarctic continental margin in the eastern

Abstract: Two land/sea seismic refraction experiments were carried out by the Alfred Wegener Institute in 1990 and 1992 to increase the understanding of the crustal structure of the volcanic passive margin in the eastern Weddell Sea off Dronning Maud Land. Four profiles were measured, two parallel to the margin between 12°W and 4°W and two perpendicular t8°W. These data are the first seismic velocity measurements obtained for the entire crust offshore Dronning Maud Land. The interpretations of the seismic sections reveal velocity distributions which are typical of continental crust at volcanic passive margins. The lower crust exhibits velocities up to 7.5 km s-1, which indicates magmatic intrusions or underplating. The basement is overlain by the volcanic extrusions of the Explora Wedge, which has a maximum thickness of 8 km. The crust hins northwards from 40 km thickness near the ice edge to less than 25 km. Because of the velocity distribution i the crust and the assumption that he continental margin was created above a mantle plume, the margin can be regarded asan analogue of the continental margin in the North Atlantic (East Greenland and Vering Margin).) i ~ Africa U