Cenozoic planktonic foraminiferal palaeoecology inferred from isotopic and trace element geochemical signals

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Author(s): Bhatia, Rehmat; Schmidt, Daniela N.; Wade, Bridget; Manning, Christina J.; Mattey, David; Muller, Wolfgang; Spratt, John; Robinson, Marci M.; Evans, David; Thornalley, David; Ridgwell, Andy
Author Affiliation(s): Primary:
University of Bristol, School of Earth Sciences, Bristol, United Kingdom
University College London, United Kingdom
Royal Holloway University of London, United Kingdom
Goethe University Frankfurt, Germany
Natural History Museum, United Kingdom
U. S. Geological Survey, United States
University of Saint Andrews, United Kingdom
Volume Title: AGU 2018 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2018; American Geophysical Union 2018 fall meeting, Washington, DC, Dec. 10-14, 2018. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: The trace element and isotopic geochemistry of planktonic foraminiferal species, both in recent and deep time, is affected by their ecology. However, foraminifera have been known to adapt their ecologies, in response to physical and biogeochemical changes in the ocean. This adds uncertainty to proxy signals used to construct long-term palaeoclimate records. Therefore, validating ecology is particularly important for species used to reconstruct intervals of dramatic climate change in Earth history, such as the Paleocene-Eocene Thermal Maximum, and the Middle Miocene Climatic Optimum. We adopt a multi-proxy approach to investigate the palaeoecology of multiple Eocene and Miocene species using individual foraminifera analysis (IFA). IFA enables potential heterogeneity of geochemical signatures within individuals in a population to be evaluated. Using well preserved specimens from various size fractions, we acquired paired carbon and oxygen isotope and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) data, and electron microprobe analysis (EMPA) trace element data for species with unresolved palaeoecologies from New Jersey (ODP Leg 174AX), Maryland (South Dover Bridge), Hampden Beach, Tanzania and Site U1338 (IODP Expedition 320/321, eastern equatorial Pacific). LA-ICPMS data, and Mg/Ca trace element maps of specimens from South Dover Bridge will be presented, and the palaeoecological and palaeoclimatic interpretations discussed. LA-ICPMS single chamber and size constrained data of Eocene species (except Globigerina cf. bulloides) suggest minimal effect of ontogeny on Mg/Ca, B/Ca and Sr/Ca. EMPA derived Mg/Ca maps of Eocene and Miocene species show intra-shell Mg/Ca heterogeneity alike to modern species, and Mg/Ca band thickness also varies between symbiotic and asymbiotic species.
Year of Publication: 2018
Research Program: IODP Integrated Ocean Drilling Program
ODP Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; Atlantic Coastal Plain; Cenozoic; East Pacific; Expedition 321; Expeditions 320/321; Foraminifera; Geochemistry; IODP Site U1338; Integrated Ocean Drilling Program; Leg 174AX; Microfossils; Miocene; Neogene; North Pacific; Northeast Pacific; Ocean Drilling Program; Pacific Equatorial Age Transect; Pacific Ocean; Paleocene-Eocene Thermal Maximum; Paleoecology; Paleogene; Planktonic taxa; Tertiary; Trace elements; United States
Coordinates: N023000 N120500 W1175800 W1421000
N383000 N402800 W0740000 W0753500
Record ID: 2019061713
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