CORRELATION BETWEEN ISOTOPE RECORDS IN MARINE AND CONTINENTAL CARBON RESERVOIRS NEAR THE PALEOCENE EOCENE BOUNDARY

CHANGES in the isotope content of the large marine carbon reservoir can force shifts in that of the smaller carbon pools in the atmosphere and on land. The carbon isotope compositions of marine carbonate sediments from the late Palaeocene vary considerably, exhibiting a sudden decrease close to the Palaeocene/Eocene boundary which coincides with deep-sea benthic extinctions1 and with changes in ocean circulation. Here we report that these fluctuations in the marine carbon isotope record are closely tracked by the terrestrial records provided by palaeosol carbonates and mammalian tooth enamel. In using palaeosol carbonates to reconstruct the CO2 content of the ancient atmosphere2, isotope shifts of this sort will have to be taken into account. The sharp decrease in C-13/C-12 ratios in the late Palaeocene provides a datum for precise correlation of marine and continental records, and suggests that abrupt climate warming at this time may have played an important role in the evolution of land mammals.