Seismic Structures of the Eastern Bransfield Basin, Antarctic Peninsula

Abstract

The Basin, a marginal basin located between the Antarctic Peninsula and the South Shetland Islands, isconsist of three small basins, the Central, Eastern, Western Basins. Seismic data obtained on December1995 show well-defined spreading ridges, basement highs, faults, morphology of the basin, distribution ofsediments, crustal and sedimentary deformation, diapirs, and contourites. The main spreading axis of theCentral Bransfield Basin connecting Deception and Bridgeman Islands continues up to the central part ofthe Eastern Basin, whereas deep basin covered by thick sediments without any spreading structures developsin the northeastern part. This indicates that back-arc spreading along the axis of the Bransfield Basin hasbeen taken place in the southwestern part of the Eastern Basin, not in the northeastern part. Many NW-SEtrending faults perpendicular to the axis of the basin would be related with strike-slip movement of theShackleton Fracture. Zone. Extensinal strutures like deep basin without any spreading structures in thenortheastern part, normal faults and diapirs on both continental slopes of the Eastern Basin would be formedby extension as a consequence of the sinistral movement between Antarctic and the Scotia plates.