Purdue News  December 27, 2004  Antarctic iced over when
greenhouse gases – not ocean currents – shifted, study suggests
WEST LAFAYETTE, Ind. – A longstanding theory that provides much
of the basis for our understanding of climate change – that the
mile-thick ice sheet covering Antarctica developed because of a
shift in ocean currents millions of years ago – has been
challenged by Purdue University scientists.  revised conception
of current flow  Download graphic caption below  Though climate
scientists have theorized for decades that the circulation of
warm ocean currents was responsible for keeping Antarctica
largely ice-free during the Eocene epoch prior to 35 million
years ago, a series of deep-sea core samples taken recently from
the ocean floor south of Australia indicates that this theory
needs reworking. The sampled sediments, which were deposited
during the period when Australia and Antarctica were beginning
to drift apart, show that cold-loving plankton, including
diatoms and dinoflagellates, were