Late Paleogene (Eocene to Oligocene) Paleoceanography of the Northern North Atlantic.
Abstract
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.
Document Details
- Document Type
- Technical Report
- Publication Date
- Nov 01, 1982
- Accession Number
- ADA121674
Entities
People
- Kenneth George Miller
Organizations
- Woods Hole Oceanographic Institution