On a continent on which over 99% of the lans is now covered with ice sheets, paradoxically some of the most common fossils are those of plants. They indicate that, for most of its history, Antarctica was a green forested land, even though the continent was situated over the South Pole. The fossils contain a rich store of climate information that provides a window into past greenhouse worlds with ice-free poles.
The evolution of Antarctic climate from a Cretaceous greenhouse into the Neogene icehouse is captured within a rich record of fossil leaves, wood, pollen and flowers from the Antarctic Peninsula and the Transantarctic Mountains. About 85 million years ago, during the mid-Late Cretaceous, flowering plants thrived in sub-tropical climates in Antarctia. Analysis if their leaves and flowers, many of which were ancesteors of plants that live in the tropics today, indicates that summer temperatures averaged 20oC during this global thermal maximum. During the Palaeocene (~60Ma) warmth-loving plants gradually lost their place in the vegetation and were replaced by floras dominated by araucarian conifers (monkey puzzles) and the southern beech
Nothofagus, which tolerated freezing winters. Plants hung on tenaciously in high latitudes, even after ice sheets covered the land, and during periods of interglacial warmth in the Neogene small dwarf plants survived in tundra-like conditions only 500 km of the South Pole.
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Speaker
Jane Francis (Leeds)
Biography
Jane Francis is Professor of Palaeoclimatology and Head of the School of Earth and Environment at the University of Leeds. Her research focuses on ancient climate change, particularly in the polar regions, the areas on Earth most responsive to environmental change. She uses fossil plants as a tool to understand the nature of past climates and to investigate the response of polar environments to climate change millions of years ago. She has undertaken twelve expeditions to the Arctic and Antarctica and was awarded the Polar Medal by H.M. Queen for her contribution to British polar research.
