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The Role of Hudson Strait Outlet in Younger Dryas Sedimentation
in the Labrador Sea
Harunur Rashid
Byrd Polar Research Center, Ohio State University, Columbus, Ohio, USA
David J. W. Piper
Geological Survey of Canada (Atlantic), Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada
Benjamin P. Flower
College of Marine Science, University of South Florida, St. Petersburg, Florida, USA
In the Younger Dryas (YD) the circum-North Atlantic region returned to near
glacial conditions, widely attributed to the release of fresh water from the Lauren-
tide Ice Sheet (LIS). Hudson Strait was a major outlet for fresh water, icebergs, and
sediment from the LIS that deposited Heinrich (H) layers throughout the North
Atlantic. Heinrich layer 0 (H0), the YD equivalent ice-rafting event, has been
reported to be absent in deep water seaward of the mouth of Hudson Strait. We
have identi
ed meter-thick H0 carbonate-rich sediments of YD age seaward of
Hudson Strait as nepheloid-
ow deposits and as turbidites on the northeast Sohm
Abyssal Plain. Otherwise, H0 is generally absent in cores from the Labrador Basin.
The thick proximal H0 bed indicates an important supply of fresh water through the
Hudson Strait outlet of the LIS during the YD. The sparse distal sediment distri-
bution and values in the planktonic foraminiferal
18
O in the Labrador Sea, less
depleted than during H1, were probably the result of the position of the ice margin,
duration of freshwater discharge, and dilution of freshwater signature with the
ambient seawater during H0. This change is interpreted to result from differences
in the retreat of the ice margin at the mouth of Hudson Strait, resulting in different
styles of sediment and freshwater transport during the H0 compared to earlier H
events.
δ
1. INTRODUCTION
The last deglaciation was interrupted by a near glacial,
millennial-scale Younger Dryas (YD) cooling event in the
Northern Hemisphere from 12.9 to 11.6 ka. Evidence for the
YD equivalent event is found in ice cores, marine sediment
cores, and continental paleoarchives [Alley and Clark, 1999].
It is marked by a ~10°C mean annual temperature fluctuation
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