Late Paleocene-middle Eocene benthic Foraminifera on a Pacific seamount (Allison Guyot, ODP Site 865); greenhouse climate and superimposed hyperthermal events

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doi: 10.1002/2015PA002837
Author(s): Arreguín-Rodríguez, Gabriela J.; Alegret, Laia; Thomas, Ellen
Author Affiliation(s): Primary:
Universidad de Zaragoza, Departamento de Ciencias de la Tierra, Saragossa, Spain
Yale University, Spain
Volume Title: Paleoceanography
Source: Paleoceanography, 31(3), p.346-364. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0883-8305 CODEN: POCGEP
Note: In English. NSF Grant OCE-720049. 163 refs.; illus., incl. 2 tables
Summary: We investigated the response of late Paleocene-middle Eocene (∼60-37.5 Ma) benthic foraminiferal assemblages to long-term climate change and hyperthermal events including the Paleocene-Eocene Thermal Maximum (PETM) at Ocean Drilling Program (ODP) Site 865 on Allison Guyot, a seamount in the Mid-Pacific Mountains. Seamounts are isolated deep-sea environments where enhanced current systems interrupt bentho-pelagic coupling, and fossil assemblages from such settings have been little evaluated. Assemblages at Site 865 are diverse and dominated by cylindrical calcareous taxa with complex apertures, an extinct group which probably lived infaunally. Dominance of an infaunal morphogroup is unexpected in a highly oligotrophic setting, but these forms may have been shallow infaunal suspension feeders, which were ecologically successful on the current-swept seamount. The magnitude of the PETM extinction at Site 865 was similar to other sites globally, but lower diversity postextinction faunas at this location were affected by ocean acidification as well as changes in current regime, which might have led to increased nutrient supply through trophic focusing. A minor hyperthermal saw less severe effects of changes in current regime, with no evidence for carbonate dissolution. Although the relative abundance of infaunal benthic foraminifera has been used as a proxy for surface productivity through bentho-pelagic coupling, we argue that this proxy can be used only in the absence of changes in carbonate saturation and current-driven biophysical linking. Abstract Copyright (2016), . American Geophysical Union. All Rights Reserved.
Year of Publication: 2016
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Allison Guyot; Assemblages; Benthic taxa; C-13/C-12; Carbon; Cenozoic; East Pacific; Eocene; Faunal list; Foraminifera; Greenhouse effect; Invertebrata; Isotope ratios; Isotopes; Leg 143; Marine environment; Microfossils; Mid-Pacific Mountains; North Pacific; Northeast Pacific; O-18/O-16; ODP Site 865; Ocean Drilling Program; Oxygen; Pacific Ocean; Paleocene; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoenvironment; Paleogene; Protista; Quantitative analysis; Seamounts; Stable isotopes; Tertiary; Upper Paleocene
Coordinates: N182624 N182626 W1793320 W1793321
Record ID: 2016056322
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom