Evidence for global cooling in the Late Cretaceous
Authors:
Linnert et al
Abstract:
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 less than approximately 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.
Tuesday, June 17, 2014
The Late Cretaceous Climate was Cooling During the Campanian to Maastrichtian
Labels:
campanian,
cretaceous,
maastrichtian,
paleoclimate,
paleoenvironment,
paleooceans
Subscribe to:
Post Comments (Atom)
No comments:
Post a Comment