Seismic structures of the western Bransfield Strait, Antarctic Peninsula: rift propagation from northeast to southwest

Abstract

Bransfield Strait is a marginal basin formed by recent extension between the northern Antarctic Peninsula and the South Shetland Islands. New seismic profiles obtained from the western Bransfield Strait show the variation of crustal structures along the strait: (1) well-defined volcanic ridges in the axial deep of the basin to the NE of Deception Island, (2) many small-scale volcanic structures in the vicinity of Deception Island associated with Deception Island volcanism, (3) extensive crustal deformation by a series of normal faults without axial volcanism to the SW of Deception Island. This variation is clear evidence of NE to SE rift propagation from initial seafloor spreading in the Central Bransfield Basin to continental crustal extension in the Western Bransfield Basin. Deception Island is a bathymetric and tectonic boundary between the two basins, and may have acted as a frontal volcanic center to initiate new seafloor spreading or a barrier to rift propagation into the Western Bransfield Basin.