A 100-million-year-old fossil forest discovered by chance on an island east of New Zealand provides new insights into ancient life close to the South Pole. Researchers found large trees, early flowering plants, seed cones and rare insects preserved in rock in the Chatham Islands. These are believed to be the first records of life close to the South Pole during the Cretaceous period, a time of extreme greenhouse conditions from 145 million to 65 million years ago.
Palaeontologist Associate Professor Jeffrey Stilwell and palaeobotanist Dr Chris Mays from Monash University’s School of Geosciences led the research team, which included Professor David Cantrill from the Royal Botanic Gardens Melbourne.
Associate Professor Stilwell says the fossils throw light on the formerly unknown life of the Cretaceous period, when many southern continents including New Zealand and the Chatham Islands (Zealandia), Australia, Antarctica and South America were still mostly joined together as part of the southern landmass Gondwana.
“One hundred million years ago, the Earth was in the grip of a greenhouse effect – a planet of extreme heat with minimal ice (except in the high altitudes) and sea levels of up to 200 metres higher than today,” Associate Professor Stilwell says.
“Rainforests inhabited by dinosaurs existed in subpolar latitudes and polar ecosystems were adapted to long months of winter darkness and summer daylight. Never before have we had evidence about what life existed near the South Pole 90 million to 100 million years ago, or the conditions that life on land experienced.”
The discovery was made in one of the most remote known fossil locations in the Southern Hemisphere while researchers were investigating a bone bed on Chatham Island and plant remains on nearby Pitt Island.
“The discovery attests to a completely different type of ecosystem around 100 million years ago, revealing the first insights into specific strategies these plants and animals evolved to cope with extreme greenhouse conditions, and months of light and alternating darkness,” Dr Mays says.
