Deep-sea benthic foraminiferal turnover across early Eocene hyperthermal events at Northeast Atlantic DSDP Site 550

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doi: 10.1016/j.palaeo.2016.03.010
Author(s): Arreguín-Rodríguez, G. J.; Alegret, L.
Author Affiliation(s): Primary:
Universidad de Zaragoza, Departamento de Ciencias de la Tierra, Saragossa City, Spain
Volume Title: Palaeogeography, Palaeoclimatology, Palaeoecology
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.451, p.62-72. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 88 refs.; illus., incl. 1 plate, sketch map
Summary: Several extreme warming events, called hyperthermals, superimposed the warming trend of the early Paleogene. Deep-sea benthic foraminifera suffered major extinction during the most severe of those events, the Paleocene-Eocene Thermal Maximum, but their response to the following, less severe hyperthermals has been documented at very few locations. We evaluate and compare the benthic foraminiferal assemblages across ETM2 and H2 events at DSDP Site 550 in the NE Atlantic Ocean. The CIE and carbonate dissolution were more severe during ETM2 than during the H2 event. Early Eocene benthic foraminiferal assemblages were moderately diverse and strongly dominated by calcareous taxa, and they consisted of mixed infaunal and epifaunal morphogroups. They responded similarly to ETM2 and H2 events, showing a decrease in absolute abundance, an increase in the relative abundance of agglutinated taxa, indicative of more carbonate-corrosive waters, and a marked decrease in the percentage of Bolivinoides decoratus, suggesting a lower food supply during hyperthermals. However, some differences in their response were also noted. Oligotrophic taxa such as Nuttallides truempyi and Quadrimorphina profunda increased in relative abundance during early ETM2, whereas Globocassidulina subglobosa and Osangularia sp. 1, opportunistic species which may indicate pulsed food inputs, peaked during the H2 event. We conclude that both hyperthermal events represent a general disruption of an overall meso-oligotrophic environment, with less food reaching the seafloor combined with increased CaCO3 corrosivity of bottom waters. We did not find clear evidence for decreasing primary productivity during the hyperthermal events, and the apparent low food delivery to the seafloor may have been related to an increase in benthic foraminiferal metabolic rates due to the higher temperatures, with a more severe lack of food during ETM2 than during H2. The benthic foraminiferal response thus appears to be scaled to the magnitude of hyperthermals. Abstract Copyright (2016) Elsevier, B.V.
Year of Publication: 2016
Research Program: DSDP Deep Sea Drilling Project
IPOD International Phase of Ocean Drilling
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Benthic taxa; C-13/C-12; Carbon; Cenozoic; Cluster analysis; DSDP Site 550; Deep Sea Drilling Project; Deep-sea environment; Eocene; Eocene Thermal Maximum 2; Foraminifera; H2 event; Hyperthermal events; IPOD; Invertebrata; Isotope ratios; Isotopes; Leg 80; Lower Eocene; Marine environment; Microfossils; North Atlantic; Northeast Atlantic; O-18/O-16; Oxygen; Paleoecology; Paleogene; Protista; Stable isotopes; Statistical analysis; Temperature; Tertiary
Coordinates: N483054 N483055 W0132622 W0132623
Record ID: 2016058800
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands