New analysis of a sediment core from Antarctica documents recurring surface fires in a prehistoric rainforest roughly 90 million years ago, the most southerly wildfire record known. With the nearest volcanic activity at least 400 km away, researchers conclude lightning was the likely ignition source. Charcoal, amber-producing charred trunks, and abundant peat-moss spores indicate that repeated surface fires helped convert rainforest to raised peatland — a process that offers lessons for modern peatlands under climate change.
Ancient Wildfires Near the South Pole: How Lightning Turned Antarctic Rainforests Into Peatlands
(James McKay via SWNS)
New research published in Communications Earth & Environment reveals compelling evidence that recurring wildfires swept through a prehistoric Antarctic rainforest about 90 million years ago, producing the southernmost wildfire record yet identified.
Ignition and Climate Context
The team found that the nearest known volcanic activity at the time lay at least 400 kilometres away, making lightning the most plausible ignition source for the blazes. During the Late Cretaceous, mean annual temperatures near the South Pole reached roughly 53°F (12°C), warm enough to sustain rainforest ecosystems despite several months of winter darkness each year.
(Photo by Vladyslav Dukhin via Pexels)
What the Sediment Core Revealed
Researchers re-examined the same sediment core first reported in Nature (2020) and identified microscopic charcoal fragments concentrated in younger strata. Those charcoal particles indicate predominantly soft conifer wood burned at comparatively low temperatures, consistent with surface-level fires rather than canopy-consuming infernos. Fire-altered trunks appear to have produced amber, and abundant peat-moss spores point to the formation of an early raised bog closely associated with repeated burning.
Salzmann, co-first author of the study, said: 'Ninety million years ago, just 900 kilometres from the South Pole, a temperate and very swampy Antarctic rainforest with pronounced dry and monsoon seasons gradually silted up and developed into a peatland dominated by peat mosses. Wildfires, which became increasingly frequent, clearly played a decisive role in this process. They kept the vegetation open and enabled the development of a peat bog where ground-level smouldering fires then occurred repeatedly.'
Modern Relevance
These findings improve our understanding of how fire regimes and peatland ecosystems interact under warm, high-CO2 climates. The study provides valuable analogues for how contemporary peatlands may respond to warming and increased wildfire risk under ongoing climate change.
Study Source: Communications Earth & Environment. Original rainforest discovery first reported in Nature (2020).
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