Goteborg University, Sweden

Carbon isotope, mesofossil, and qualitative palynological analyses have been undertaken through the Cobham Lignite Bed, Kent, England, which overlies the late Paleocene Upnor Formation and underlies the early Eocene lower Woolwich Shell Beds. Carbon isotope analysis has demonstrated a negative carbon isotope excursion similar to that seen in the lower part of the carbon isotope excursion that marks the onset of the Paleocene-Eocene Thermal Maximum (PETM) elsewhere in the marine and continental record. The carbon isotope excursion interval in the Cobham Lignite is shown to be characterized by repeated fires in a vegetation dominated by flowering plant trees and herbs and with many ferns. The abundance of ferns is likely to be a response to disturbance caused by fires. This detailed evidence from across the early PETM (as identified by stratigraphic context and a negative carbon isotope excursion), combined with data from less stratigraphically resolved, but almost coeval, macrofloras from other southern English sites, shows that there is no major change in vegetation at this time in southern England. In contrast, vegetation change occurs later with the emplacement of floras of the Eocene Thermal Maximum. Although there is no obvious vegetation response to the global warming at the PETM, the abundance and consistent occurrence of charcoal in this interval is unparalleled elsewhere in the southern English Paleogene. Therefore, repeated fires, at least on a local scale, may have been one environmental response to the events around the PETM.