Evidence for global cooling in the Late Cretaceous.

• Published in: Nature Communications
• Main Authors: Linnert, Ch., Robinson, S.A., Lees, J.A., Bown, P.R., Pérez-Rodríguez, I., Petrizzo, M.R., Falzoni, F., Littler, K., Arz, J.A., Russell, E.E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2014
• Subjects: North Atlantic
• Online Access: http://zaguan.unizar.es/record/57818; https://doi.org/10.1038/ncomms5194

The Late Cretaceous ‘greenhouse’ world witnessed a transition from one of the warmest climates of the past 140 million years to cooler conditions, yet still without significant continental ice. Low-latitude sea surface temperature (SST) records are a vital piece of evidence required to unravel the cause of Late Cretaceous cooling, but high-quality data remain illusive. Here, using an organic geochemical palaeothermometer (TEX86), we present a record of SSTs for the Campanian–Maastrichtian interval (~83–66¿Ma) from hemipelagic sediments deposited on the western North Atlantic shelf. Our record reveals that the North Atlantic at 35¿°N was relatively warm in the earliest Campanian, with maximum SSTs of ~35¿°C, but experienced significant cooling (~7¿°C) after this to <~28¿°C during the Maastrichtian. The overall stratigraphic trend is remarkably similar to records of high-latitude SSTs and bottom-water temperatures, suggesting that the cooling pattern was global rather than regional and, therefore, driven predominantly by declining atmospheric pCO2 levels.