Development of abyssal circulation in the eastern North Atlantic: benthic foraminiferal carbon isotopic evidence

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

OSTI ID:6197656

Miller, K G; Fairbanks, R G; Thomas, E

The eastern basin of the northern North Atlantic at present is ventilated by overflow of the Iceland-Faeroe Ridge, Faeroe Bank Channel, and Wyville-Thompson Ridge. The evolution of Cenozic abyssal circulation of this region was related to tectonic opening and subsidence of these sills. The authors used delta/sup 13/C records of the benthic foraminifera Cibicidoides to decipher the timing of tectonically-controlled changes in bottom-water circulation in the eastern North Atlantic. Records from Site 608 show that from about 24 to 15 Ma delta/sup 13/C values in Kings Trough were depleted compared to western North Atlantic values and were, in fact, more similar to Pacific values. This reflects lower ventilation of the Kings Trough region compared to the well-oxygenated western North Atlantic. Oligocene delta/sup 13/C comparisons of Site 119 (Bay of Biscay) with western North Atlantic records suggests that the eastern basin was also relatively isolated prior to 24 Ma. At about 15 Ma, delta/sup 13/C values at Site 608 attained values similar to the western North Atlantic, indicating increased eastern basin ventilation in the middle Miocene. This increased advection into the eastern basin pre-dated a major delta/sup 18/O increase which occurred at about 14.6 Ma. Subsidence estimates of the Greenland-Scotland Ridge indicate that the deepening of the Iceland-Faeroe Ridge was coincident with the marked change in eastern basin deep-water ventilation.

• Research Organization: Columbia Univ., Palisades, NY (USA)
• OSTI ID: 6197656
• 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
580100 -- Geology & Hydrology-- (-1989)
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
580400 -- Geochemistry-- (-1989)
AGE ESTIMATION
ANIMALS
ATLANTIC OCEAN
CARBON ISOTOPES
CENOZOIC ERA
CHEMICAL COMPOSITION
CHEMISTRY
FORAMINIFERA
GEOCHEMISTRY
GEOLOGIC AGES
INVERTEBRATES
ISOTOPE RATIO
ISOTOPES
MICROORGANISMS
OCEANIC CIRCULATION
OCEANOGRAPHY
OXYGEN ISOTOPES
PLATE TECTONICS
PROTOZOA
SARCODINA
SEA BED
SEAS
SEDIMENTS
SURFACE WATERS
TECTONICS
TERTIARY PERIOD