Geochemical evidence for combustion of hydrocarbons during the K-T impact event.
It has been proposed that extensive wildfires occurred after the Cretaceous-Tertiary (K-T) impact event. An abundance of soot and pyrosynthetic polycyclic aromatic hydrocarbons (pPAHs) in marine K-T boundary impact rocks (BIRs) have been considered support for this hypothesis. However, nonmarine K-T BIRs, from across North America, contain only rare occurrences of charcoal yet abundant noncharred plant remains. pPAHs and soot can be formed from a variety of sources, including partial combustion of vegetation and hydrocarbons whereby modern pPAH signatures are traceable to their source. We present results from multiple nonmarine K-T boundary sites from North America and reveal that the K-T BIRs have a pPAH signature consistent with the combustion of hydrocarbons and not living plant biomass, providing further evidence against K-T wildfires and compelling evidence that a significant volume of hydrocarbons was combusted during the K-T impact event.
Belcher
Claire M
CM
Department of Earth Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, United Kingdom. claire.belcher@ucd.ie
Finch
Paul
P
Collinson
Margaret E
ME
Scott
Andrew C
AC
Grassineau
Nathalie V
NV
D004190:Disasters / Q000266:history*; D055593:Geological Phenomena; D049690:History, Ancient; D006838:Hydrocarbons / Q000737:chemistry*; D019110:Meteoroids; D009656:North America; D011084:Polycyclic Aromatic Hydrocarbons / Q000737:chemistry*; D053260:Soot
D006838:Hydrocarbons; D011084:Polycyclic Aromatic Hydrocarbons; D053260:Soot