Antarctic sediment core reveals ancient transition from greenhouse to icehouse

New Scientist : A single marine sediment core has revealed Antarctica’s climatological history from tropical forest to icy wasteland, according to Ulrich Salzmann of Northumbria University in Newcastle upon Tyne, UK, and his colleagues. Collected from the seafloor off Wilkes Land in East Antarctica during the Integrated Ocean Drilling Program , the core contains pollen grains that indicate a change in vegetation between 54 million and 12 million years ago. During the Eocene epoch, when its temperature hovered around 16 °C, the continent was covered with lush tropical forests, which included palms and monkey puzzle trees. By the early Oligocene, those trees had been replaced by more temperate species, including pines, conifers, and beeches. By the Miocene, some 23 million years ago, temperatures had dropped to about 6 °C and mosses and similar tundra plants had begun to take over. All greenery disappeared around 12.5 million years ago when the glaciers took over. Understanding Antarctica’s climate history may become important as climate change causes the continent to once more warm up and its ice to melt. Salzmann and his team presented their work at the April meeting of the European Geosciences Union General Assembly in Vienna.