Eocene to Oligocene oceanography and temperatures in the Antarctic Indian Ocean

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doi: 10.1002/9781118668061.ch3
Author(s): Barrera, Enriqueta; Huber, Brian T.
Author Affiliation(s): Primary:
University of Michigan, Department of Geological Sciences, Ann Arbor, MI, United States
Smithsonian Institution, United States
Volume Title: Antarctic paleoenvironment; a perspective on global change; Part two
Volume Author(s): Kennett, James P., editor; Warnke, Detlef A.
Source: The Antarctic paleoenvironment; a perspective on global change; Part two, edited by James P. Kennett and Detlef A. Warnke. Antarctic Research Series, Vol.60, p.49-65. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0066-4634. ISBN: 978-1-118-66806-1 CODEN: ANTSA4
Note: In English. 71 refs.; illus. incl. 2 tables, sketch maps
Summary: Oxygen and carbon isotopic analyses of benthic and planktonic foraminiferal species from the lower Eocene to Oligocene section at Ocean Drilling Program sites 738 and 744 in the Indian Ocean provide insights into the response of polar surface and deep waters during a major climatic cooling and development of continental glaciation on Antarctica. Based on isotopic ranking and delta13C values of planktonic foraminiferal species, there is no evidence for major changes in upwelling or productivity as a consequence of cooling at the high latitudes from Early Eocene to Early Oligocene time. The planktonic foraminiferal data indicate that the thermal structure of the water column changed little, not only from Early to Late Middle Eocene but also from Late Eocene to Early Oligocene time. A 1.0 per mill decrease in delta18O values of both planktonic and benthic foraminifera occurred at about 42 Ma. Results of high-resolution analyses across the Eocene-Oligocene transition indicate the following: a 1.4 per mill positive shift in foraminiferal delta18O values occurred in sediments at the base of Chron 13N deposited at 35.85 Ma; the highest Oligocene Cibicidoides delta18O values (2.5 per mill) occurred from 35.85 to 35.24 Ma; increased continental ice accumulation in the Early Oligocene increased the average oceanic delta18O composition by at least 0.6 per mill. (Auth.)
Year of Publication: 1993
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Antarctica; C-13/C-12; Carbon; Cenozoic; Chemical composition; Cooling; Eocene; Foraminifera; Indian Ocean; Invertebrata; Isotope ratios; Isotopes; Leg 119; Marine sediments; Microfossils; O-18/O-16; ODP Site 738; ODP Site 744; Ocean Drilling Program; Ocean circulation; Oligocene; Oxygen; Paleo-oceanography; Paleoclimatology; Paleogene; Productivity; Protista; Salinity; Sea water; Sediments; Stable isotopes; Temperature; Tertiary; Upwelling
Coordinates: S624233 S624232 E0824715 E0824714
S613440 S613439 E0803528 E0803527
Record ID: 1994044011
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from the Antarctic Bibliography, United States