Antarctic Tectonics: Constraints From an ERS-1 Satellite Marine Gravity Field
David McAdoo,
Seymour Laxon
A high-resolution gravity field of poorly charted and
ice-covered ocean near West Antarctica, from the Ross Sea east to the Weddell Sea, has been derived with the use of satellite altimetry, including ERS-1 geodetic phase, wave-form data. This gravity field reveals regional tectonic fabric, such as gravity lineations, which are
the expression of fracture zones left by early (65 to 83 million years
ago) Pacific-Antarctic sea-floor spreading that separated the Campbell
Plateau and New Zealand continent from West Antarctica. These
lineations constrain plate motion history and confirm the hypothesis
that Antarctica behaved as two distinct plates, separated from each
other by an extensional Bellingshausen plate boundary active in
the Amundsen Sea before about 61 million years ago.
D. McAdoo is with the Geosciences Laboratory, National Ocean
Service, National Oceanic and Atmospheric Administration, Silver
Spring, MD 20910, USA. S. Laxon is with Mullard Space Science
Laboratory, Department of Space and Climate Physics, University College
London, Dorking, Surrey RH5 6NT, UK.
