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TitleThe influence of meltwater on the Labrador Current in Heinrich event 1 and the Younger Dryas
AuthorLi, G; Piper, D J W
SourceQuaternary Science Reviews vol. 107, 2015 p. 129-137,
Alt SeriesEarth Sciences Sector, Contribution Series 20130382
Mediapaper; on-line; digital
File formatpdf
ProvinceEastern offshore region; Northern offshore region
NTS3; 14; 15; 16; 27; 28; 38; 39
AreaLabrador Sea; Flemish Pass
Lat/Long WENS-80.0000 -32.0000 78.0000 46.0000
Subjectssurficial geology/geomorphology; stratigraphy; geochemistry; glacial history; meltwater channels; silts; Younger Dryas; Labrador Current; Heinrich event 1; Cenozoic; Quaternary
Illustrationslocation maps; profiles; plots
ProgramMarine Geohazards, Public Safety Geoscience
AbstractThe Labrador Current transports freshwater from the Arctic regions to the northern Atlantic and the freshwater flux can influence the meridional overturning circulation. The response of the Labrador Current to meltwater processes is unclear during the deglaciation of the ice sheets around the northwest Atlantic. This study utilized cores from Flemish Pass to monitor variations in the strength of the Labrador Current by using the sortable-silt proxy. Carbonate silt was removed by acid treatment in order to remove the effects of variable source grain size. The carbonate content, the amount of ice-rafted detritus and XRF chemical data were measured to indentify the main meltwater events in the last glaciation. This study observed a clear enhancement of the flow strength of the Labrador Current in Heinrich Event 1 and the Younger Dryas, with the greatest flow strength during the Younger Dryas event. The onset of the current enhancement was dated at 13.3 ka cal BP, which preceded enhanced ice-rafted deposition by several hundred years. The current enhancement in the Flemish Pass during the Younger Dryas event corresponds to the freshening of the surface water revealed by oxygen isotopes. The potential sources of melt water are from Hudson Strait and southern Labrador. Thus meltwater preceding significant iceberg supply has an important effect on the Labrador Current in Heinrich-type events on the Laurentide Ice Sheet margin.
Summary(Plain Language Summary, not published)
Basic science arising from Public Safety Geoscience seabed cores. Strong freshwater supply through Hudson Strait during retreat of the Laurentide Ice Sheet increased the speed of the Labrador Current during events 16 and 12 thousand years ago. During the younger event, freshwater supply preceded supply of abundant icebergs by a few hundred years. These observations contribute to debates about drivers of North Atlantic ocean circulation and effects of future Greenland ice sheet melting.