Contact:     Eliot Hurwitz             FOR IMMEDIATE RELEASE
                                       4/24/97

Using a new method of analyzing radar echoes, scientists have finally determined one of the final puzzle pieces that show how the present arrangement of continents evolved after the breakup of a single massive continent about 180 million years ago.

The radar echoes have enabled scientists to "see" the so-called tectonic structure of fracture zones hidden beneath the sea ice off the shores of Antarctica, according to an article in today's Science magazine by scientists from the National Oceanic and Atmospheric Administration and England's Mullard Space Science Lab.

In a classic scientific detective story, Dr. Dave McAdoo of NOAA's Geosciences Lab and Dr. Seymour Laxon of University College of London sifted through hundreds of gigabytes of data to find evidence of the new plate, called the Bellinghausen Plate.

In the past two years, tremendous advances have been made in visualizing the geologic structures beneath the sea floor using high accuracy satellite measurements of the contour of the sea surface that reflect the underlying shape of the seafloor. However, data from the polar regions has been unusable up to now because of the interference of sea ice. McAdoo and Laxon developed a method involving the re-analysis of individual radar echoes to retrieve accurate height measurements even when sea ice was present.

The existence of the tectonic plate, active before 60 million years ago, has been theorized for many years, but until today there was no way to verify its existence or accurately visualize its contours.

"This result is likely to have a major impact on our understanding of the breakup of Gondwanaland and the tectonic evolution of Antarctica," McAdoo said.

Final, edited copies of the article are available from the AAAS News and Information Office.