FLORAL TURNOVER AT THE K/T BOUNDARY: AN ISOTOPIC AND MOLECULAR STUDY FROM THE WESTERN INTERIOR OF NORTH AMERICA
Carbon isotopic data, expressed as δ13C values in , of bulk organic matter and of specific molecules are presented, which reflect the state of the carbon cycle at the time of organic matter deposition. Study of the molecular fossils contained within this matter allows constraint to be placed on the causes of any isotopic disturbances, thus pyrolysis and GC-MS techniques are employed.
The asynchronous recoveries of δ13C values and terrestrial ecosystems indicate that the carbon isotopes reflect changes to the carbon cycle independent of terrestrial plant succession. The shape of the excursion provides information on the source of the isotopically light carbon in the atmosphere coincident with the KTB.
Further samples from Eurasia and New Zealand are being studied in order to assess the wider environmental effects of events at the K/T boundary.