The Pre-Quaternary history of fire

Abstract

Although evidence for land vegetation comes from the Silurian, and maybe even earlier, the first record of fossil charcoal (fusain) is from the late Devonian. For this period there are only one or two isolated records. Not until the Early Carboniferous is there a record of extensive charcoal deposits, mainly preserved in near-shore clastic sediments, which provide evidence of significant and widespread wildfires. By the late Carboniferous charcoal was common or abundant in a wide range of facies, including tropical wetland peats. Wildfire played an important role in shaping the environment at this time. The latest Palaeozoic and early Mesozoic records of charcoal are fewer, whereas important deposits of late Mesozoic age are found worldwide. The occurrence of charcoal at the Cretaceous–Tertiary Boundary has been highlighted as evidence for a global fire following a meteorite impact, but this interpretation is questionable. Charcoal has been widely reported from Tertiary sediments and its appearance in the Quaternary and Recent is not solely as a result of human impact. Through the past 400 million years there have been major changes in atmospheric oxygen levels that affected fire intensity and frequency. Fire systems thus have a long history and their impact on shaping the environment is assessed.