Satellites provide new insights into polar geophysics

Abstract

A revolution in polar geophysics is under way thanks to altimeter data, which the ERS satellites have been collecting since 1991. Geophysical surveys in the polar regions have long been hampered by inaccessibility, particularly in areas that are covered yearround by sea ice or land ice. As a result the major remaining uncertainties in global tectonic models of the Mesozoic and Cenozoic tend to lie in the Arctic and Antarctic regions. In fact, major tectonic plate boundaries have been hypothesized, but not confirmed, for both regions. In the Arctic, a divergent plate boundary associated with the Mesozoic opening of the Canada Basin has been proposed [e.g., Lawver et al ., 1990] while in the Antarctic a divergent boundary, active during the late Cretaceous in the Amundsen Sea, has been hypothesized [ Cande et al ., 1995; Stock and Molnar , 1987]. Due to the acute sparseness of seafloor surveys in these areas, however, no one has been able to prove that these plate boundaries actually existed, nor has anyone been able to locate extinct remnants of the boundaries. High‐resolution marine gravity fields (Figures 1 and 2) derived from satellite altimeter data are now redressing this problem of sparse surveys.