Evidence for global cooling in the Late Cretaceous.

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 <~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.

SUBMITTER: Linnert C 

PROVIDER: S-EPMC4082635 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature