A forest fire and soil erosion event during the Late Devonian mass extinction

• We find a forest fire and soil erosion event during the Devonian mass extinction.
• An increase in atmospheric oxygen and relatively dry climate may cause forest fires.
• Forest fires lead to massive soil erosion.
• Massive soil erosion induces the marine mass extinction.

The Late Devonian mass extinction occurred in a stepwise manner and culminated close to the Frasnian–Famennian (F–F) boundary (372 million years ago). Organic-molecular indices from marine sedimentary rocks at the Sinsin section, Belgium, indicate that the sequence of combustion of land vegetation, soil erosion, and anoxia–euxinia occurred close to this boundary. The increased concentrations of biomarkers indicating forest fire and soil erosion measured in the Sinsin section suggest that fire became widespread at this time, leading to various damaging consequences (increased runoff and oceanic anoxia) that caused marine extinctions. Magnetic susceptibility data in the Sinsin section indicate a relatively dry climate spanning the F–F boundary, which would have encouraged forest fires. The study of organic biomarkers presents several lines of evidence to link forest fire and soil erosion to the Late Devonian mass extinction.

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