Where kilometres-thick ice now covers West Antarctica, marshy forests grew around 90 million years ago, and fires raged regularly within them. A new study shows that the fires may even have contributed to the formation of early peat bogs.
An international research team led by Johann P. Klages from the Alfred Wegener Institute (AWI) examined a sediment core from the Amundsen Sea. It was recovered during a Polarstern expedition off the coast of West Antarctica and contains remnants of a forest floor dating back some 90 million years. At that time, the region was only about 900 kilometres from the South Pole.
In the sediments, the researchers discovered microscopic charcoal, tree resin altered by fire and other traces of burning. These were presumably mainly ground fires and smouldering fires, likely triggered by lightning.
Antarctica looked completely different back then than it does today. In the late Cretaceous period, a moderately warm climate prevailed near the South Pole. Conifers, ferns and other plants formed swampy forests, despite the polar night lasting several months.
Recurring fires may have cleared the vegetation, thereby promoting the spread of peat mosses of the genus Sphagnum. This may have led to the formation of early peat bogs capable of storing large amounts of carbon.
The study “Co-evolution of wildfires and early Sphagnum-peatlands near the Cretaceous South Pole” was published on 7 September 2026 in Communications Earth & Environment. It paints a picture of an Antarctica where forests and peatlands existed and fires burned where massive ice sheets lie today.
Heiner Kubny, PolarJournal