Evidence for a volcanic rifted margin and oceanic crustal structure for the Falkland Plateau Basin

Marine geophysical data from the western Falkland Plateau show strongly lin eated magnetic anomalies and a coincident linear gravity high that identify the southeastern margin of a Falkland Islands block as a volcanic rifted c ontinental margin. Characteristics of onshore and offshore dykes suggest th is margin is most probably slightly younger than 190 Ma. Together with thes e data, seismic reflection profiles and sonobuoy seismic refraction data fr om the basin province of the Falkland Plateau east of the islands indicate an elevated oceanic origin for the major part of the Falkland Plateau Basin , most probably within the Karoo hotspot province. These conclusions are co mpatible with, but do not directly indicate the independent rotation of a F alkland Islands block, and closely constrain models of southwest Gondwana e volution.