Multi-site, multi-proxy records of 'hyperthermals' at the onset of middle-late Eocene cooling

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Author(s): Kirtland, S. E.; Sexton, P. F.; Norris, R. D.
Author Affiliation(s): Primary:
University of California, San Diego, Scripps Institution of Oceanography, San Diego, CA, United States
Open University, United Kingdom
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: Few detailed records exist of the onset of cooling towards the end of the Early Eocene Climatic Optimum (from 50 to 47.5 Ma). A 2.4 Myr benthic foraminiferal stable isotope record from Demerara Rise (ODP Site 1258) in the equatorial Atlantic demonstrated that this long-term cooling was punctuated by a series of orbitally-paced, rapid warming events. These abrupt warming events exhibit similar features to the well-known Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma), but their shorter duration (∼40 kyr), smaller magnitude, faster recoveries, and repeated occurrence suggest a different mechanism responsible for their genesis. While these events were identified by isotopic evidence from Demerara Rise, the existence of coincident decreases in wt % CaCO3 at two other sites (ODP Site 1267 in the Southern Atlantic and ODP Site 1210 in the central Pacific) suggests they represent global carbon cycle perturbations and warming events. Here, we present high resolution (<2 kyr) bulk stable isotope records and X-ray fluorescence core scanning-derived estimates of iron, calcium, and biogenic Ba for five of the largest of these events at all three sites (ODP Site 1258, ODP Site 1267, and ODP Site 1210). These detailed records support our inter-site correlations and allow a comparison of events in time and space. Additionally, our records provide detailed information on the internal structure of events, with implications for processes involved in their genesis and recovery.
Year of Publication: 2011
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Calcium carbonate; Carbon; Carbon cycle; Cenozoic; Climate change; Demerara Rise; Eocene; Equatorial Atlantic; Geochemical cycle; Isotopes; Leg 198; Leg 207; Leg 208; Middle Eocene; North Atlantic; North Pacific; Northwest Atlantic; Northwest Pacific; ODP Site 1210; ODP Site 1258; ODP Site 1267; Ocean Drilling Program; Pacific Ocean; Paleocene; Paleocene-Eocene Thermal Maximum; Paleogene; Shatsky Rise; South Atlantic; Spectra; Stable isotopes; Tertiary; Upper Eocene; Walvis Ridge; West Atlantic; West Pacific; X-ray fluorescence spectra
Coordinates: N092600 N092600 W0544400 W0544400
N321300 N321300 E1581600 E1581600
Record ID: 2018028765
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