The Palaeocene “top chron C27n” transient greenhouse episode: evidence from marine pelagic Atlantic and peri‐Tethyan sections

Abstract

Terra Nova, 24, 477–486, 2012AbstractThe early Cenozoic, which is punctuated by several negative carbon isotope excursions (CIEs), was a time of climatic and oceanographic transition from ‘Greenhouse’ to ‘Icehouse’ conditions. The occurrence of a ∼0.5‰ CIE starting at the top of Chron C27n (TC27N) is reconfirmed with stable isotope data from Zumaia (Spain) and Bjala (Bulgaria) localities. Spectral analysis on respective carbonate/magnetic susceptibility proxy records substantiates the orbital cyclostratigraphy allowing correlation to a high‐resolution benthic foraminifera isotope record from ODP Pacific Site 1209, that indicates a coeval 2 °C transient warming. The hyperthermal event lasts ∼200 ka, contrasting with other short‐lived events from the Eocene, and displays a relatively rapid onset and a longer tailing back to pre‐event values similar to the Palaeocene–Eocene Thermal Maximum (PETM), though lower in amplitude. That a causal trigger for the TC27N event may be the onset of volcanism in the North Atlantic Igneous Province (NAIP) can be inferred from a ∼200‐m‐thick lava pile erupted during C27n/C26r polarity transition in the E Greenland margin.