The demise of the early Eocene greenhouse; decoupled deep and surface water cooling in the eastern North Atlantic

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doi: 10.1016/j.gloplacha.2016.08.010
Author(s): Bornemann, André; d'Haenens, Simon; Norris, Richard D.; Speijer, Robert P.
Author Affiliation(s): Primary:
Bundesanstalt für Geowissenschaften und Rohstoffe, Hanover, Germany
Yale University, United States
University of California at San Diego, United States
Katholieke Universiteit Leuven, Belgium
Volume Title: Global and Planetary Change
Source: Global and Planetary Change, Vol.145, p.130-140. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0921-8181
Note: In English. Includes appendix. 105 refs.; illus., incl. sect.
Summary: Early Paleogene greenhouse climate culminated during the early Eocene Climatic Optimum (EECO, 50 to 53 Ma). This episode of global warmth is subsequently followed by an almost 20 million year-long cooling trend leading to the Eocene-Oligocene glaciation of Antarctica. Here we present the first detailed planktic and benthic foraminiferal isotope single site record (δ13C, δ18O) of late Paleocene to middle Eocene age from the North Atlantic (Deep Sea Drilling Project Site 401, Bay of Biscay). Good core recovery in combination with well preserved foraminifera makes this site suitable for correlations and comparison with previously published long-term records from the Pacific Ocean (e.g. Allison Guyot, Shatsky Rise), the Southern Ocean (Maud Rise) and the equatorial Atlantic (Demerara Rise). Whereas our North Atlantic benthic foraminiferal δ18O and δ13C data agree with the global trend showing the long-term shift toward heavier δ18O values, we only observe minor surface water δ18O changes during the middle Eocene (if at all) in planktic foraminiferal data. Apparently, the surface North Atlantic did not cool substantially during the middle Eocene. Thus, the North Atlantic appears to have had a different surface ocean cooling history during the middle Eocene than the southern hemisphere, whereas cooler deep-water masses were comparatively well mixed. Our results are in agreement with previously published findings from Tanzania, which also support the idea of a muted post-EECO surface-water cooling outside the southern high-latitudes.
Year of Publication: 2016
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Bay of Biscay; C-13/C-12; Carbon; Cenozoic; Climate change; Cores; DSDP Site 401; Deep Sea Drilling Project; Eocene; Foraminifera; Greenhouse effect; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 48; Lower Eocene; Microfossils; North Atlantic; Northeast Atlantic; O-18/O-16; Oxygen; Paleo-oceanography; Paleoclimatology; Paleogene; Paleotemperature; Protista; Stable isotopes; Stratigraphic boundary; Surface water; Tertiary
Coordinates: N472538 N472540 W0084837 W0084838
Record ID: 2016103509
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands