TY - JOUR
T1 - The early opening of the Equatorial Atlantic gateway and the evolution of Cretaceous peak warming
AU - Dummann, Wolf
AU - Hofmann, Peter
AU - Olaf Herrle, Jens
AU - Frank, Martin
AU - Wagner, Thomas
N1 - Funding Information:
This research used samples provided by the Deep Sea Drilling Project (DSDP) and was funded by German Research Foundation grants to Hofmann and Herrle (grants HO2188/9 and HE3521/9-2). Cinzia Bottini, Elisabetta Erba, and Hironao Matsumoto are thanked for providing reference data. We thank Stuart Robinson and two anonymous reviewers for their valuable comments and suggestions.
Publisher Copyright:
© 2023 The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license.
PY - 2023/5
Y1 - 2023/5
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=85153956005&partnerID=8YFLogxK
U2 - 10.1130/g50842.1
DO - 10.1130/g50842.1
M3 - Article
SN - 0091-7613
VL - 51
SP - 476
EP - 480
JO - Geology
JF - Geology
IS - 5
ER -
