Late paleogene (eocene to oligocene) paleoceanography of the northern North Atlantic. Doctoral thesis
Technical Report
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OSTI ID:6762680
Seismic stratigraphic evidence indicates that a major change in abyssal circulation occurred in the latest Eocene-earliest Oligocene of the North Atlantic. Reflector R4 reflects a change from weakly (Eocene) to vigorously circulating bottom water (early Oligocene). Sediment distribution studies indicate a northern source for this bottom water, probably from the Arctic via the Norwegian-Greenland Sea/Faeroe-Shetland Channel. Current-controlled sedimentation and erosion continued through the Oligocene; however, above reflector R3 (upper Oligocene), the general intensity of abyssal currents decreased. Above reflector R2 (lower Miocene) a further reduction in abyssal currents resulted in more coherent current-controlled sedimentation and a major phase of sediment drift development. Major deep-sea benthic foraminiferal changes occurred between the middle Eocene and earliest Oligocene: an agglutinated assemblage was replaced by a calcareous assemblage (abyssal Labrador Sea), and an indigenous Eocene calcareious fauna became extinct (abyssal Bay of Biscay). In shallower Atlantic sites (< 3km paleodepth), a Nuttallides truempyi assemblage was replaced by an assemblage of long- and wide-ranging taxa in the early late Eocene.
- Research Organization:
- Woods Hole Oceanographic Institution, MA (USA)
- OSTI ID:
- 6762680
- Report Number(s):
- AD-A-121674/6
- Country of Publication:
- United States
- Language:
- English
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Mon Dec 31 23:00:00 EST 1984
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Mon Dec 31 23:00:00 EST 1984
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Mon Dec 31 23:00:00 EST 1984
· Geol. Soc. Am., Abstr. Programs; (United States)
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OSTI ID:6321466