Hydrocarbon compound evidence in marine successions of South China for frequent wildfires during the Permian-Triassic transition

Abstract

Combustion - derived polycyclic aromatic hydrocarbons (PAHs) are frequently used as molecular proxies for wildfire in recent and ancient sediments. Here, we document the abundances of four hydrocarbon compounds, i.e., phenanthrene (Phe), benzo[ e ]pyrene (BeP), benzo[ ghi ]perylene (Bpery), and coronene (Cor), across the Permian–Triassic boundary (PTB) in five marine sections of South China. High values of PAHs are present below the end-Permian mass extinction (EPME) horizon, from the Clarkina changxingensis Zone to the Clarkina yini Zone, suggesting strong perturbations to terrestrial ecosystems predating the marine crisis. PAHs peaked in the uppermost C. yini Zone, correlative with the EPME, reflecting simultaneity of the most severe phases of the terrestrial and marine crises. The proxy records document suitable climatic conditions for wildfires (high p O 2 ) throughout the P-Tr transition. The results of the present study are also significant in validating the utility of BeP, Bpery, Cor, and BeP/Phe as proxies for terrestrial wildfires in deep-time marine successions. • Polycyclic aromatic hydrocarbons (Phe, BeP, Bpery, Cor) are paleo-wildfire proxies. • These PAHs were identified in five marine P-Tr boundary sections of South China. • Wildfires were common before, during, and after the P-Tr mass extinction. • Atmospheric p O 2 was sufficient during the P-Tr transition to permit wildfires. • Terrestrial habitat devastation contributed to the marine mass extinction.