Ancient temperate rainforest discovered near South Pole from 90-million-year-old cores
Scientists analyzing a seabed core from West Antarctica uncovered fossil roots, pollen and amber that prove a temperate rainforest existed near the South Pole about 90 million years ago.
During a 2017 drilling expedition aboard the German research vessel Polarstern, researchers recovered a sediment core from nearly a kilometre-deep site in the Amundsen Sea, close to the Pine Island and Thwaites glaciers. Examination revealed a distinct layer of ancient soil hosting a dense network of fossilised roots, large quantities of pollen and spores, and millimetre-scale amber fragments, confirming that a temperate rainforest grew at a palaeolatitude of about 82° south in the Cretaceous.
The forest endured prolonged polar night yet persisted, with reconstructed mean annual temperatures near 12 °C and summer averages around 19 °C. Climate simulations indicate that such conditions required an almost ice-free Antarctica and atmospheric CO₂ concentrations of roughly 1,120-1,680 ppm. The amber, named Pine Island amber, offers potential for future microscopic analyses of the ancient ecosystem. Together, the root, pollen, spore and chemical evidence provide a rare, detailed snapshot of a once-wet, forested polar landscape now buried beneath the Southern Ocean floor.
Why it matters
The discovery shows how dramatically Earth's climate and ecosystems can shift under different atmospheric conditions.
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