Abrupt deglaciation events and Holocene palaeoceanography from high-resolution cores,Cartwright Saddle,Labrador Shelf,Canada |
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| Authors: | J T Andrews L Keigwin F Hall Anne E Jennings |
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| Abstract: | The uppermost Quaternary sediments in Cartwright Saddle, Labrador Shelf, are acoustically laminated, with reflectors that can be traced over long distances. Two piston cores from the saddle record changes in sediment and meltwater delivery from the northeast margin of the Laurentide Ice Sheet (LIS) during deglaciation. Variations in sediment properties indicate a similar history of sediment accumulation over the last 12 kyr. The temporal sampling interval reaches decadal resolution in the last deglacial period 7–9 ka. Analyses of total carbonate content, sediment magnetic variables, foraminiferal species and stable isotope measurements on planktic foraminifers show that abrupt changes occurred ca. 10.9, 9.2, 8.8, 7.9 and 7 ka (with 450 yr correction). There was no distinct change in sediment character during much of the Younger Dryas chronozone. In the δ18O record, the 8.8 ka event is a dramatic 1‰ shift toward lower values, which we associate with the Noble Inlet glacial event within Hudson Strait. We do not see the pronounced low δ18O event at 7.1 ka reported off Nova Scotia, but surprisingly, neither the Nova Scotia records nor other records in the Labrador Sea capture the impressive 8.8 ka change. Serious consideration must be given to the final collapse of the LIS as the cause of the 8.2 cal. ka cold event recorded in Greenland and northwest Europe. Copyright © 1999 John Wiley & Sons, Ltd. |
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| Keywords: | Labrador Shelf Laurentide Ice Sheet meltwater event 8 2 cal ka event |
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