Paleoceanographic Trends on the Northern Scotian Shelf

Abstract

Paleoceanographic trends are recorded and reflected in the preservation of benthonic foraminiferal assemblages in ocean floor sediments. This study presents a succession of foraminiferal assemblages from an 8m core taken within St. Anne's Basin on the N.E. Scotian Shelf.

This micropaleontological study reveals the changes in bottom water characteristics from approximately 8000 yrs.b.p. During the early postglacial a fauna dominated by I. teretis indicates cold water temperatures, similar to the present Outer Labrador Current. From approximately 5000-7000 yrs.b.p. a warm water fauna reflects the mid-Holocene hypsithermal. The next change in bottom water occurred in the last 5000 yrs.b.p. with an abrupt cooling which is associated with a greater influence of the Outer Labrador Current. The most recent change has occurred in the last 2000 yrs. with an abrupt cooling associated with influence of the Inner Labrador Current. A warm water fauna at the surface was determined to be displaced, probably from a topographic high just to the south.

The main paleoceanographic trends are due to north-south shifts in the position of the Gulf Stream and Labrador Currents and to varying degrees of influence of each.

Distinct Holocene-Pleistocene paleoceanographic events have been previously distinguished in several basins on the Scotian and Labrador Shelf. The record presented here closely resembles a record from a core in nearby Canso Basin in that it reflects an almost complete Holocene record.

Keywords: Pages: Supervisors: David Scott