Having analyzed the data collected by our survey ship "Ocean IV" in the Bransfield Strait in 1991, we recognized that the geomorphology, gravity and magnetic anomalies trending NE direction along bandings. The sediments in the Bransfield Strait can be subdivided into two sequences: the first rifting sequence and the second rifting sequence. The basement was faulted into a half-graben in northwestern side of the Bransfield trough. Considering the crustal structure crossing the South Shetland Islands, the Bransfield Strait and the Antarctic Peninsula, we propose a two-phase rifting tectonic evolution model and a layered-shear model for the lithospheric deformation under the effects of extensional stress field
