Peatland wildfires in the Lower Cretaceous Damoguaihe Formation, Hailar Basin, Northeast China

Wildfires were prominent in Earth's terrestrial ecosystems during the Cretaceous greenhouse period with significant climate and vegetation evolution. In this study, we investigated the evidence of peatland wildfires in the Lower Cretaceous Damoguaihe Formation (lower Albian) in the Yimin coalfield, Hailar Basin. Macro-charcoal, fusain, pyrogenic inertinites, and polycyclic aromatic hydrocarbons (PAHs) in the studied coal seam indicate that wildfires occurred frequently during peat accumulation. Wildfires were dominated by low-temperature fires with a lower frequency of moderate- to high-temperature fires. The phenanthrene, fluoranthene, and pyrene in the coal seam are mainly derived from low-temperature combustion. The vertical variation of combustion products (charcoal and PAHs) in the peatland profile indicates the changes in frequency and intensity of wildfires during the deposition. The observed angiosperm-derived charcoal suggest that angiosperms adapted to the harsh peatland environment in the Damoguaihe Formation.