State University of New York at Binghamton, United States

The South Orkney Microcontinent (SOM) is the biggest (250X350 km) continental element of the South Scotia Ridge between the Antarctic and the Scotia Plate. The northern margin of the SOM is the Antarctic-Scotia Plate boundary with a sinistral strike-slip movement accomplished by an oblique plate convergence in the western part, and a divergence component eastward toward the Bruce Bank. Seismic and gravity data show two main domains with different structural trends related to the complexity of the geodynamic activity in the surroundings: a) in the southern part of the SOM the north-south trend of Airy, Bouguer and Eotvos basins formed during the Oligocene extensional phase of the Scotia Ridge fragmentation and formation of the Powell and Jane basins to the south-east and south-west margins of the SOM respectively, b) in the northern part of the SOM, and east-west trend following the transform plate boundary, affected the structure of the basement high and the Newton Basin.