Cenozoic record of elongate, cylindrical, deep-sea benthic Foraminifera in the Indian Ocean (ODP Sites 722, 738, 744, 758, and 763)

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doi: 10.2113/gsjfr.40.2.113
Author(s): Hayward, Bruce W.; Sabaa, Ashwaq T.; Thomas, Ellen; Kawagata, Shungo; Nomura, Ritsuo; Schröder-Adams, Claudia; Gupta, Anil K.; Johnson, Katie
Author Affiliation(s): Primary:
Geomarine Research, Auckland, New Zealand
Yale University, United States
Shimane University, Japan
Carleton University, Canada
Indian Institute of Technology, India
Volume Title: Journal of Foraminiferal Research
Source: Journal of Foraminiferal Research, 40(2), p.113-133. Publisher: Cushman Foundation for Foraminiferal Research, Ithaca, NY, United States. ISSN: 0096-1191 CODEN: JFARAH
Note: In English. NSF Grant OCE-720049; includes 8 appendices. 92 refs.; illus., incl. 2 tables
Summary: A group of approximately 100 species of elongate, cylindrical deep-sea benthic foraminifera (families Stilostomellidae, Pleurosto-mellidae, Nodosariidae) with complex, often constricted apertural structures, became extinct during increasingly cold glacial periods in the late Pliocene to mid-Pleistocene Climate Transition (MPT, approximately 2.6-0.6 Ma). We document the evolutionary history and architecture of this Extinction Group (Ext. Gp) through the Cenozoic at four lower bathyal-upper abyssal Indian Ocean sites (ODP 722, 744/738, 758, 763), seeking clues to the cause of this morphologically-targeted extinction episode late in the Cenozoic. Eighty percent of the 116 Ext Gp. species present in the Cenozoic of the Indian Ocean originated globally in the Eocene or earlier, compared with 23-37% of other Quaternary deep-sea foraminifera. The Ext. Gp had its peak species richness and relative and absolute abundances in the late Eocene. The rapid warming of the Paleocene-Eocene Thermal Maximum, that resulted in a loss of 30-50% of deep-sea foraminiferal species, had no impact on the Ext. Gp in the one Indian Ocean section (ODP 744/738) studied. Major Cenozoic changes in the Ext. Gp, including increased species turnover, changes in dominant species, a decline in abundance, loss in diversity, and finally extinction, mostly occurred during the middle Eocene to early Oligocene, middle to late Miocene, and late Pliocene to middle Pleistocene. These were times of stepped increase in the volume of polar ice, global oceanic cooling, surface-water eutrophication, seasonality of phytoplankton production, deep-water ventilation, and southern deep-water carbonate corrosiveness. The final decline and disappearance of the Ext. Gp began in the late Miocene at high latitudes (744/738), but not until the late Pliocene (758, 763) or MPT (722) at lower latitudes. We hypothesize that the loss of the Ext. Gp of deep-sea foraminifera may have been caused by the decline or demise of their specific food source (detrital phytoplankton or bottom-dwelling microbes) that was abundant in the Greenhouse World and was decimated by the stepwise cooling, ventilation, or eutrophication of the oceans that began in the middle and late Eocene.
Year of Publication: 2010
Research Program: ODP Ocean Drilling Program
Key Words: 10 Paleontology, Invertebrate; Arabian Sea; Benthic taxa; Cenozoic; Deep-sea environment; Exmouth Plateau; Extinction; Foraminifera; Indian Ocean; Invertebrata; Kerguelen Plateau; Leg 117; Leg 119; Leg 121; Leg 122; Marine environment; Microfossils; Morphology; Ninetyeast Ridge; ODP Site 722; ODP Site 738; ODP Site 744; ODP Site 758; ODP Site 763; Ocean Drilling Program; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoecology; Paleoenvironment; Paleogene; Protista; SEM data; Southern Ocean; Tertiary
Coordinates: N163718 N163719 E0594746 E0594745
N052302 N052303 E0902141 E0902140
S203512 S203511 E1121232 E1121231
S624233 S613439 E0824715 E0803527
Record ID: 2010037732
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Abstract, Copyright, Cushman Foundation for Foraminiferal Research, Reference includes data from GeoScienceWorld, Alexandria, VA, United States