3D model of a sector of the South Scotia Ridge (Antarctica)

A three-dimensional geological model was built to show and analyse a northern sector of the Scotia-Antarctica transform plate boundary. The South Scotia Ridge is a 400km long submerged continental structural high representing the eastern continuation of the Antarctic Peninsula. South Scotia Ridge runs approximately in the E-W direction, separating Scotia Sea Plate from Antarctica Plates. Structures, due to the transform plate margin, are considered to be concentrated inside this continental high. The three-dimensional model, built using seismic profiles and a digital elevation model, is a powerful tool to visualize and help to understand deep geological structures. Maps and profiles, on the contrary, only give a two-dimensional view, and do not show the structure of the continental-oceanic boundary at depth. The model shows that the deformation style of the continental-oceanic boundary, and of the oceanic crust nearby, is related to the left-lateral movement of the main transform fault system. Furthermore, it seems to be connected to the orientation and geometry of the South Scotia Ridge with respect to the homogeneous deformation regime, which affects the entire Scotia Plate. Moving from west to east, the NW-dipping main fault surface becomes almost vertical with a sinistral strike-slip movement in the central sector. To the east, a south-dipping plane decreases its inclination and changes orientation (from E-W to ESE-WNW): here shortening features are visible. The three-dimensional geological model presents a western and central province wherein the continental-oceanic boundary involves the fragmented continental blocks, the continental slope, the oceanic basement and sediments. The sedimentary cover and the oceanic basement are not deformed in the eastern province.