Ancient Antarctic fjords

Abstract

The East Antarctic ice sheet, the largest in the world, lies seemingly frozen in time. Discovery of a rugged landscape buried beneath the thick ice provides evidence of a more dynamic past. See Letter p.72 The East Antarctic ice sheet has played a fundamental part in modulating climate and sea level during the past 30 million years. Understanding its history is crucial to evaluating its future behaviour and response to global warming. Airborne ice-penetrating radar studies now reveal a fjord-like landscape beneath several kilometres of ice in the East Antarctic Aurora subglacial basin. The data confirm, and provide a new constraint on, the magnitude and dynamics of the oscillations of the East Antarctic ice sheet during the late Cenozoic, which had previously been supported only by marine cores.