Abstract

The high-CO2 world of the Cretaceous allowed plants and animals to thrive on Antarctica, even though the continent was situated over the South Pole. Warmth-loving plants, similar to those those that live in the tropics today, suggest that at times during the Late Cretaceous summer temperatures may have been as high as 20°C at 65°S, supporting the widely-held view that the Cretaceous was a time of global warmth and ice-free. However, new evidence from sediments of latest Cretaceous age (~70 Ma) indicates that by the end of the Cretaceous the polar climate was cold enough to allow sea ice to form. Peaks in the abundance of certain marine plankton, correlated with low temperatures from oxygen isotopes, imply that at times sea ice formed around the Antarctic margin, further suggesting that ice caps were present on the Antarctic continent itself.