Early Holocene large-scale meltwater discharge from Greenland documented by foraminifera and sediment parameters

Records of foraminiferal assemblages combined with lithological properties (grain size, magnetic parameters and XRF data) of marine sediment cores from West Greenland coastal waters and the adjacent Labrador Sea document widespread early Holocene meltwater discharge. This discharge is concluded to o...

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Bibliographic Details
Published in:Palaeogeography, Palaeoclimatology, Palaeoecology
Main Authors: Seidenkrantz, Marit-Solveig, Ebbesen, H., Aagaard-Sørensen, S., Moros, M., Lloyd, J.M., Olsen, Jesper, Knudsen, Mads Faurschou, Kuijpers, A.
Format: Article in Journal/Newspaper
Language:English
Published: 2013
Subjects:
Greenland
Early Holocene
Meltwater discharge
Foraminifera
Sediment properties
Magnetic susceptibility
8.2 ka event
SUBPOLAR NORTH-ATLANTIC
ABRUPT CLIMATE-CHANGE
GLACIAL LAKE AGASSIZ
ICE-SHEET
WEST GREENLAND
BENTHIC FORAMINIFERA
LABRADOR SEA
COOLING EVENT
INNUITIAN ICE
FRESH-WATER
Glacial Lake
Ice Sheet
Labrador Sea
North Atlantic
Online Access:https://pure.au.dk/portal/en/publications/9bd1813b-b567-4d22-8a0c-2d8b327afac0
https://doi.org/10.1016/j.palaeo.2012.04.006
http://www.scopus.com/inward/record.url?scp=84888199893&partnerID=8YFLogxK
Description
Summary:Records of foraminiferal assemblages combined with lithological properties (grain size, magnetic parameters and XRF data) of marine sediment cores from West Greenland coastal waters and the adjacent Labrador Sea document widespread early Holocene meltwater discharge. This discharge is concluded to originate from large-scale melting of the Greenland Ice Sheet (GIS) having started prior to 8600 cal.yr BP and ended at about 7700-7500 cal. yr BP, when the GIS margin had withdrawn from the fjords and become mainly land-based. The benthic foraminiferal record from one of the coastal sites mainly reflects West Greenland Current (WGC) subsurface water properties and to a minor degree surface productivity. The most significant feature in this record is an abrupt shift to a higher-productivity regime around similar to 7700 cal.yr BP. We suggest that the cessation of a widespread GIS meltwater discharge at that time favoured an increased influence of (sub)surface water of Atlantic origin and initiation of modern subpolar gyre circulation enabling Labrador Sea deep convection. Further offshore, a record of planktonic foraminiferal assemblages shows an oceanographic change at ca. 9500 cal. yr BP, whilst a gradual but marked change in the planktonic foraminiferal assemblage between 8800 and 7000 cal.yr BP may be related to a narrowing of the WGC low-salinity surface water belt. The oceanic regime off West Greenland prior to similar to 7800 cal.yr BP was thus characterised by the presence of a permanent and widespread meltwater surface layer, presumably preventing deep convection in this region. Apart from indications of a slight decrease in meltwater discharge by the benthic foraminiferal fauna data, neither of the records show any clear signal of a regionally important 8.2 ka event. (C) 2012 Elsevier B.V. All rights reserved.

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