Antarctica was the centerpiece of the Gondwana supercontinent. About 13,900 km of Antarcticas 15,900-km-long continental margins (87 percent) are of rifted divergent type, 1600 km (10 percent) were converted from a subduction type to a passive margin after ridge-trench collision along the Pacific side of the Antarctic Peninsula, and 400 km (3 percent) are of active convergent type. In recent years the volume of geophysical data along the continental margin of Antarctica has increased substantially, which allows differentiation of the crustal characteristics of its continent-ocean boundaries and transitions (COB/COT). These data and geodynamic modeling indicate that the cause, style, and process of breakup, separation and shelf formation were quite different along the Antarctic margins. A circum-Antarctic map shows the crustal styles of the margins and the location and geophysical characteristics of the COT. The data indicate that only a quarter of the rifted margins are of volcanic type. About 70 percent of the rifted passive margins contain extended continental crust stretching between 50 and 300 km oceanward of the shelf edge. Identifications of the COT/COB and an understanding of its process of formation and crustal thinning have consequences for plate-kinematic reconstructions, geodynamic syntheses and the generation of paleobathymetric and paleotopographic grids for paleo-climate simulations.
Helmholtz Research Programs > PACES I (2009-2013) > TOPIC 3: Lessons from the Past > WP 3.2: Tectonic, Climate and Biosphere Development from Greenhouse to Icehouse