Circum-Antarctic continent-ocean transition zones

• Main Author: Gohl, Karsten
• Format: Conference Object
• Language: unknown
• Published: 2008
• Subjects: Antarctic; Antarctic Peninsula; New Zealand; Pacific; Southern Ocean; The Antarctic; Antarc*; Antarctica
• Online Access: https://epic.awi.de/id/eprint/18108/; https://hdl.handle.net/10013/epic.28642

Antarctica was a center piece of the Gondwana supercontinent. About 85 percent of Antarcticas 10000 km long continental margins are of a rifted divergent type, and about 1200 km have been converted from a subduction-type to a passive margin after ridge-trench collision along the Pacific side of the Antarctic Peninsula. The separation of South America, Africa, India, Australia and New Zealand from Antarctica and the creation of a continuous Southern Ocean began in the Jurassic and continued until the mid Tertiary. In recent years, the amount of geophysical data along the continental margin of Antarctica has increased substantially, which allows to differentiate the crustal characteristics of its continent-ocean boundaries and transitional zones (COB/COT). The data and geodynamic modelling indicate that the cause, style and process of breakup and separation were quite different along the Antarctic margin. A circum-Antarctic map will show the crustal styles or the margin and the location and geophysical characteristics of the COT. About 70 percent of the rifted passive margins contain extended continental crust stretching more than 50 km oceanwards of the shelf edge. Most of these extended margins have a continent-ocean transition with a width of more than 100 km, in many cases up to 300 km. The total area of extended continental crust on the shelf and oceanwards of the shelf edge, including COTs with substantial syn-rift magmatic-volcanic accretion, can be estimated to be about 2.9 x 106 km2. This has implications for improved plate-kinematic and paleobathymetric reconstructions and provides new constraints for accurate calculations of isostatic responses along the Antarctic margin.