The early opening of the Equatorial Atlantic gateway and the evolution of Cretaceous peak warming

Wolf Dummann, Peter Hofmann, Jens Olaf Herrle, Martin Frank, Thomas Wagner

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3 Citations (Scopus)
60 Downloads (Pure)

Abstract

The Cretaceous opening of the Equatorial Atlantic gateway (EAG) is considered a driver of major changes in global oceanography, carbon cycling, and climate. However, the early stages of EAG opening are poorly understood. We present seawater Nd-isotope, bulk geochemical, and micropaleontological data from two South Atlantic drill cores that constrain the onset of shallow (<500 m) and intermediate (<~1000 m) water mass exchange across the EAG to 113 Ma and 107 Ma, respectively. Deep water mass exchange (>2000 m) was enabled by at least ca. 100 Ma, as much as 10 m.y. earlier than previously estimated. In response to EAG opening, deep-water ventilation in the South Atlantic, North Atlantic, and Tethys basins intensified, thereby triggering basin-scale reductions in organic carbon burial. We propose that the consequent drop in carbon sequestration in concert with increased atmospheric CO2 fluxes from subduction zones acted as major amplifiers of global warming that culminated in peak greenhouse conditions during the mid-Cretaceous.
Original languageEnglish
Pages (from-to)476-480
Number of pages5
JournalGeology
Volume51
Issue number5
Early online date15 Mar 2023
DOIs
Publication statusPublished - May 2023

ASJC Scopus subject areas

  • Geology

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