PLIOCENE PALEOCLIMATE AND EAST ANTARCTIC ICE-SHEET HISTORY FROM SURFICIAL ASH DEPOSITS

The preservation, age, and stratigraphic relation of an in situ ashfal l layer with an underlying desert pavement in Arena Valley, southern V ictoria Land, indicate that a cold-desert climate has persisted in Are na Valley during the past 4.3 million years. These data indicate that the present East Antarctic Ice Sheet has endured for this time and tha t average temperatures during the Pliocene in Arena Valley were no gre ater than 3-degrees-C above present values. One implication is that th e collapse of the East Antarctic Ice Sheet due to greenhouse warming i s unlikely, even if global atmospheric temperatures rise to levels las t experienced during mid-Pliocene times.