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Global cooling in the Late Cretaceous (free pdf)

Ben Creisler

A new paper in open access:

Christian Linnert, Stuart A. Robinson, Jackie A. Lees, Paul R. Bown,
Irene Pérez-Rodríguez, Maria Rose Petrizzo, Francesca Falzoni, Kate
Littler, José Antonio Arz & Ernest E. Russell (2014)
Evidence for global cooling in the Late Cretaceous.
Nature Communications 5, Article number: 4194

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