Effect of abyssal circulation changes on Oligocene to Miocene benthic foraminifera in the North Atlantic

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6193588

Katz, M E; Miller, K G

Benthic foraminiferal ranges at western North Atlantic Sites 563 and 558 show: 1) gradual Oligocene last occurrences in response to subsidence from the upper to lower abyssal zones; 2) a preponderance of extinctions in the early middle Miocene (about 15.5-13.5 Ma). Comparison of relative and absolute abundance changes at Site 563 sows that percentages of some taxa (e.g. Nuttallides umbonifera) reliably reflect their accumulations while percentages of others vary independently. Regional abundance changes include: 1) maxima N. umbonifera in the middle Oligocene of the deepest sites (10 and 119); 2) increased Planulina wuellerstorfi in the early middle Miocene; 3) increased N. umbonifera in the late middle Miocene. Seismic stratigraphic and delta/sup 13/C evidence indicates a northern bottom-water source for the North Atlantic throughout much of the Oligocene and Miocene. Benthic foraminifera apparently responded to bottom-water changes inferred from carbon isotopic comparisons. The extinction of relict Paleogene taxa and the ascendancy of P. wuellerstorfi in the middle Miocene apparently correlate with increased advection into the eastern Atlantic, subsidence of the Iceland-Faeroe Ridge and increased North Atlantic carbonate sedimentation. The authors speculate that this faunal reorganization was in response to global ocean chemistry changes resulting from increased ventilation of the North Atlantic.

• Research Organization: Columbia Univ., Palisades, NY (USA)
• OSTI ID: 6193588
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580500* -- Oceanography-- (1980-1989)
ANIMALS
AQUATIC ORGANISMS
ATLANTIC OCEAN
BENTHOS
BIOLOGICAL EFFECTS
BIOLOGICAL EXTINCTION
CARBON 13
CARBON ISOTOPES
CENOZOIC ERA
CHEMISTRY
EVEN-ODD NUCLEI
FORAMINIFERA
GEOCHEMISTRY
GEOLOGIC AGES
GEOLOGY
GEOPHYSICAL SURVEYS
INVERTEBRATES
ISOTOPE RATIO
ISOTOPES
LIGHT NUCLEI
MICROORGANISMS
MIOCENE EPOCH
NUCLEI
OCEANIC CIRCULATION
OCEANOGRAPHY
PALEONTOLOGY
POPULATION DYNAMICS
PROTOZOA
SARCODINA
SEAS
SEISMIC SURVEYS
STABLE ISOTOPES
STRATIGRAPHY
SURFACE WATERS
SURVEYS
TERTIARY PERIOD
WATER CHEMISTRY