As reported in the journal Nature, a groundbreaking discovery has revealed that a temperate rainforest once thrived near the South Pole during the Cretaceous period. Scientists emphasized that the fossils were not random fragments carried from elsewhere; instead, the sediment core contained an intact network of fossilized roots preserved in mudstone, alongside pollen and spores, indicating that the vegetation grew directly at the site where the core was recovered.
Fossil Roots Preserved in Place
According to the Nature study, scientists discovered a fossilized network of roots measuring three meters long in mudstone. The roots were found along with a rich array of pollen and spores dating back to the Cretaceous period, approximately 90 million years ago. This discovery took place in the Amundsen Sea of the West Antarctic shelf.
The roots were preserved in their original growth position, known as in situ, which was crucial evidence that the plants originated there rather than migrating from elsewhere. Additionally, the sediment layer contained other signs of plant life, allowing researchers to reconstruct the ecosystem. The study indicates that the rainforest existed during the Turonian to Santonian ages, around 92 million to 83 million years ago, at a palaeolatitude of nearly 82 degrees south.
A Very Different Antarctica
Today, Antarctica is the coldest and driest continent, characterized by massive ice sheets and extreme periods of darkness. However, these fossils reveal that during the Cretaceous period, the continent had a vastly different appearance.
Researchers concluded that West Antarctica once supported a temperate, swampy rainforest with conditions warm enough to sustain dense vegetation and stable soils. According to the British Antarctic Survey, the region may have experienced an annual mean temperature of around 12 degrees Celsius during that period.
These findings also indicate that Antarctica was mostly ice-free at the time. Computer modeling by the researchers suggests that atmospheric carbon dioxide levels were considerably higher than today, creating a greenhouse climate capable of supporting forests near the pole. Johann Klages and colleagues, who led the study, argued that the discovery demonstrates how sensitive polar areas are to high levels of carbon dioxide during warm periods on Earth.
Why Pollen and Spores Matter
Much of the information about the ancient landscape came from microscopic plant fossils found within the sediment layers. These microfossils are highly valuable because they have a high survival rate underground and provide clues about ancient vegetation.
According to the study, the fossil community found in the core samples is associated not only with individual plant forms but also with an entire terrestrial landscape. The pollen and fossil roots gave scientists evidence of the rainforest's existence on the southern polar coast of Antarctica. This combination of evidence made the findings more reliable, as the sediment preserved both signs of plants and their actual structures.
New Antarctic Drilling Continues to Uncover Climate History
The rainforest discovery is part of a broader scientific effort to understand Antarctica's geological past through deep sediment drilling. In February 2026, a team working on the SWAIS2C project recovered a 228-meter-long sediment core from beneath the West Antarctic Ice Sheet at Crary Ice Rise. The core holds information on ancient rocks, mud, and fossils, which could help reveal the ice sheet's behavior over millions of years of climate change.
While the 2026 drilling mission is separate from the rainforest discovery, sediment records are vital because they contain clues to Antarctica's environmental past buried under the ice.
