Abrupt changes in marine conditions, Sunneshine Fiord, eastern Baffin Island, NWT during the last deglacial transition: Younger Dryas and H-0 events

Authors:
Publisher website
Google Scholar
Abstract
Sunneshine Fiord is a shallow fiord that lies at the easternmost tip of Baffin Island, NWT, c . 66°33′ N on the western end of Davis Strait, a 600 m deep sill that links Baffin Bay to the north with the Labrador Sea and the North Atlantic in the south. Offshore surface circulation today consists principally of the southward transport of Polar Water in the Baffinland Current. Raised marine deposits in the outer part of the fiord are radiocarbon dated at >57 ka and can be associated with large lateral moraines on both walls of the fiord; Holocene raised marine sediments appear to be absent. A gravity and piston core together (HU82-031-SU5) sample about 8.5 m of the sediment fill. Nine AMS 14 C dates on marine shells and foraminifera indicate that the coring recovered sediments that span around 14 calibrated (cal) of record. Seismic surveys indicate that the upper sediment is acoustically transparent and overlies acoustically stratified materials. There is a major reflector towards the base of the cored section. Analyses of physical properties, lithofacies and biofacies indicate that there is a very sharp break in the record at around 12.4 cal ka, which is interpreted as a change from relatively ice-distal conditions to one characterized by a dramatic increase in cold, ice-proximal foraminiferal benthic species, notably Elphidium excavata forma clavata . At the same time, there was an extremely abrupt increase in detrital carbonate, most of which is dolomite. Because there is no known local source of detrital carbonate within the fiord, this abrupt event signals an increase in the transport of detrital carbonate derived from icebergs and/or meltwater from sources further north in Baffin Bay, or immediately to the south from Cumberland Sound. The onset of this event at 12. 4 cal ka is synchronous with evidence for an abrupt increase in detrital calcitic carbonate emanating from an ice re-advance within and probably across Hudson Strait. These events are the probable source of detrital calcitic carbonate in the northwestern North Atlantic associated with the Younger Dryas cold period and iceberg rafting event, H-0.

This publication has 57 references indexed in Scilit: