Isotope modeling of a mid-Turonian warming event in the South Atlantic

Author(s): Bice, K.; Pollard, D.; MacLeod, K.; Huber, B.
Author Affiliation(s): Primary:
Woods Hole Oceanographic Institution, Woods Hole, MA, United States
Pennsylvania State University, United States
University of Missouri at Columbia, United States
Smithsonian Institution, United States
Volume Title: AGU 2006 fall meeting
Source: Eos, Transactions, American Geophysical Union, 87( Fall Meeting Suppl.); American Geophysical Union 2006 fall meeting, San Francisco, CA, Dec. 11-15, 2006. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0096-3941 CODEN: EOSTAJ
Note: In English
Summary: Oxygen isotope data from very well preserved late Turonian planktonic foraminifera at DSDP Site 511 (Falkland Plateau, 60 S paleolatitude) exhibit a 2 per mil excursion to values as low as -4.7 per mil (PDB), apparently coincident with the warmest tropical temperature estimates yet obtained for the open ocean. However, local benthic foraminifer d18O show no coincident decrease. This suggests that local bottom waters experienced no temperature change while the upper ocean warmed by as much as 9C, that upper ocean waters because much more depleted due to a dramatic increase in freshwater delivery or decrease in d18O of precipitation and runoff, or that some combination of these three changes occurred. Using an isotope-capable general circulation model, we examine the likelihood that a significant upper ocean freshening or dw depletion occurred during a modest increase in local sea surface temperature during this period of overall warmer-than-modern climate. We also examine preliminary planktonic foraminiferal Mg/Ca data that support some late Turonian warming at Site 511.
Year of Publication: 2006
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Cretaceous; DSDP Site 511; Deep Sea Drilling Project; Foraminifera; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 71; Mesozoic; Microfossils; Middle Turonian; O-18/O-16; Oxygen; Paleo-oceanography; Paleoclimatology; Paleotemperature; Protista; South Atlantic; Stable isotopes; Turonian; Upper Cretaceous
Coordinates: S510017 S510017 W0465818 W0465818
Record ID: 2007070725
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