scholarly journals Early Holocene Laurentide Ice Sheet deglaciation causes cooling in the high-latitude Southern Hemisphere through oceanic teleconnection

2010 ◽  
Vol 25 (3) ◽  
Author(s):  
H. Renssen ◽  
H. Goosse ◽  
X. Crosta ◽  
D. M. Roche
Keyword(s):  
Southern Hemisphere ◽  
High Latitude ◽  
Ice Sheet ◽  
Early Holocene ◽  
Laurentide Ice Sheet

scholarly journals Simulating the Early Holocene demise of the Laurentide Ice Sheet with BISICLES (public trunk revision 3298)

2020 ◽  
Vol 13 (9) ◽  
pp. 4555-4577
Author(s):  
Ilkka S. O. Matero ◽  
Lauren J. Gregoire ◽  
Ruza F. Ivanovic
Keyword(s):  
Mass Balance ◽  
General Circulation ◽  
Ice Sheet ◽  
Circulation Model ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The North

Abstract. Simulating the demise of the Laurentide Ice Sheet covering Hudson Bay in the Early Holocene (10–7 ka) is important for understanding the role of accelerated changes in ice sheet topography and melt in the 8.2 ka event, a century long cooling of the Northern Hemisphere by several degrees. Freshwater released from the ice sheet through a surface mass balance instability (known as the saddle collapse) has been suggested as a major forcing for the 8.2 ka event, but the temporal evolution of this pulse has not been constrained. Dynamical ice loss and marine interactions could have significantly accelerated the ice sheet demise, but simulating such processes requires computationally expensive models that are difficult to configure and are often impractical for simulating past ice sheets. Here, we developed an ice sheet model setup for studying the Laurentide Ice Sheet's Hudson Bay saddle collapse and the associated meltwater pulse in unprecedented detail using the BISICLES ice sheet model, an efficient marine ice sheet model of the latest generation which is capable of refinement to kilometre-scale resolutions and higher-order ice flow physics. The setup draws on previous efforts to model the deglaciation of the North American Ice Sheet for initialising the ice sheet temperature, recent ice sheet reconstructions for developing the topography of the region and ice sheet, and output from a general circulation model for a representation of the climatic forcing. The modelled deglaciation is in agreement with the reconstructed extent of the ice sheet, and the associated meltwater pulse has realistic timing. Furthermore, the peak magnitude of the modelled meltwater equivalent (0.07–0.13 Sv) is compatible with geological estimates of freshwater discharge through the Hudson Strait. The results demonstrate that while improved representations of the glacial dynamics and marine interactions are key for correctly simulating the pattern of Early Holocene ice sheet retreat, surface mass balance introduces by far the most uncertainty. The new model configuration presented here provides future opportunities to quantify the range of plausible amplitudes and durations of a Hudson Bay ice saddle collapse meltwater pulse and its role in forcing the 8.2 ka event.

scholarly journals The effects of flowline length evolution on chemistry–δ18O profiles from Penny Ice Cap, Baffin Island, Canada

2002 ◽  
Vol 35 ◽  
pp. 150-156 ◽  
Author(s):  
David A. Fisher ◽  
Roy M. Koerner ◽  
Gregory A. Zielinski ◽  
Cameron P. Wake ◽  
Christian M. Zdanowicz ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Early Holocene ◽  
Ice Age ◽  
Laurentide Ice Sheet ◽  
Simple Extension ◽  
Baffin Island ◽  
Ice Cap ◽  
Chemical Signatures ◽  
Usual Pattern ◽  
Present Site

AbstractThe isotopic and chemical signatures for ice-age and Holocene ice from Summit, Greenland, and Penny Ice Cap, Baffin Island, Canada, are compared. the usual pattern of low δ18O, high Ca2+ and high Cl– is presented in the Summit records, but Penny Ice Cap has lower than present Cl– in its ice-age ice. A simple extension of the Hansson model (Hansson, 1994) is developed and used to simulate these signatures. the low ice-age Cl– from Penny Ice Cap is explained by having the ice-age ice originating many thousands of km inland near the centre of the Laurentide ice sheet and much further from the marine sources. Summit’s flowlines all start close to the present site. the Penny Ice Cap early-Holocene δ18O’s had to be corrected to offset the Laurentide meltwater distortion. the analysis suggests that presently the Summit and Penny Ice Cap marine impurity originates about 500 km away, and that presently Penny Ice Cap receives a significant amount of local continental impurity.

scholarly journals Surface-melt driven Laurentide Ice Sheet retreat during the early Holocene

2009 ◽  
Vol 36 (24) ◽  
Author(s):  
A. E. Carlson ◽  
F. S. Anslow ◽  
E. A. Obbink ◽  
A. N. LeGrande ◽  
D. J. Ullman ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Surface Melt

Deglaciation of the Greenland and Laurentide ice sheets interrupted by glacier advance during abrupt coolings

2020 ◽  
Author(s):  
Nicolas Young ◽  
Jason Briner ◽  
Gifford Miller ◽  
Alia Lesnek ◽  
Sarah Crump ◽  
...  
Keyword(s):  
Ice Sheets ◽  
Ice Sheet ◽  
Greenland Ice Sheet ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Baffin Island ◽  
Alpine Glacier ◽  
Baffin Bay ◽  
Warming World ◽  
Exposure Ages

<p>The early Holocene (11.7 ka to 8.2 ka) represents the most recent period when the Laurentide and Greenland ice sheets underwent large-scale recession. Moreover, this ice-sheet recession occurred under the backdrop of regional temperatures that were similar to or warmer than today, and comparable to those projected for the upcoming centuries. Reconstructing Laurentide and Greenland ice sheet behavior during the early Holocene, and elucidating the mechanisms dictating this behavior may serve as a partial analog for future Greenland ice-sheet change in a warming world. Here, we use 123 new <sup>10</sup>Be surface exposure ages from two sites on Baffin Island and southwestern Greenland that constrain the behavior of the Laurentide and Greenland ice sheets, and an independent alpine glacier during the early Holocene. On Baffin Island, sixty-one <sup>10</sup>Be ages reveal that advances and/or stillstands of the Laurentide Ice Sheet and an alpine glacier occurred in unison around 11.8 ka, 10.3 ka, and 9.2 ka. Sixty-two <sup>10</sup>Be ages from southwestern Greenland indicate that the GrIS margin experienced re-advances or stillstands around 11.6 ka, 10.4 ka, 9.1 ka, 8.1 ka, and 7.3 ka. Our results reveal that alpine glaciers and the Laurentide and Greenland ice sheets responded in unison to abrupt early Holocene climate perturbations in the Baffin Bay region. We suggest that during the warming climate of the early Holocene, freshening of the North Atlantic Ocean induced by a melting Laurentide Ice Sheet resulted in regional abrupt cooling and brief periods of ice-sheet stabilization superimposed on net glacier recession. These observations point to a negative feedback mechanism inherent to melting ice sheets in the Baffin Bay region that slows ice-sheet recession during intervals of otherwise rapid deglaciation.</p>

More on Deep Glacial Erosion by Continental Ice Sheets and Their Tongues of Distributary Ice

1988 ◽  
Vol 30 (2) ◽  
pp. 137-150 ◽  
Author(s):  
William A. White
Keyword(s):  
High Latitude ◽  
Pacific Coast ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Present Form ◽  
Laurentide Ice Sheet ◽  
Southern Chile ◽  
Open Sea ◽  
Continental Ice Sheets ◽  
Inland Ice

High latitude intracontinental seaways occupy great troughs carved by broad tongues of inland ice as it debouched to deep marine water. Such troughs occur in glaciated coasts, but not in stable, nonglaciated ones. Where ice flowed along the walls of troughs whose adjacent uplands held local glaciers, the walls simulate alpine troughs with faceted spurs and submarine hanging tributary valleys. Where uplands were not glaciated, trough walls are unbreached. Where ice flowed across them, coasts are digitate in low relief. In the northeastern sector of the Laurentide Ice Sheet, large glacial grooves converge toward the Gulf of Boothia-Prince Regent Inlet-Lancaster Sound avenue of egress to open sea, suggesting that it was an exit for inland ice which shaped it to its present form. The subduction Pacific coast of the Americas is mostly harborless in nonglaciated latitudes, but in southern Chile and British Columbia it is dissected. A circular gravity high 2800 km across is concentric with the area covered by the Laurentide Ice Sheet. Abyssal glacial silts are voluminous enough to account for an average of 100–150 m of erosion over the area covered by the Laurentide Ice Sheet.

scholarly journals Simulating the Early Holocene demise of the Laurentide Ice Sheet with BISICLES (public trunk revision 3298)

2019 ◽  
Author(s):  
Ilkka S. O. Matero ◽  
Lauren J. Gregoire ◽  
Ruza F. Ivanovic
Keyword(s):  
Mass Balance ◽  
General Circulation ◽  
Ice Sheet ◽  
Circulation Model ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The North

Abstract. Simulating the demise of the Laurentide Ice Sheet covering the Hudson Bay in the early Holocene (10-7 ka) is important for understanding the role of accelerated changes in ice sheet topography and melt in the 8.2 ka event, a century long cooling of the Northern Hemisphere by several degrees. Freshwater released from the ice sheet through a surface mass balance instability (known as the saddle collapse) has been suggested as a major forcing for the 8.2 ka event, but the temporal evolution of this pulse has not been constrained. Dynamical ice loss and marine interactions could have significantly accelerated the ice sheet demise, but simulating such processes requires computationally expensive models that are difficult to configure and are often impractical for simulating past ice sheets. Here, we developed an ice sheet model setup for studying the Laurentide Ice Sheet’s Hudson Bay saddle collapse and the associated meltwater pulse in unprecedented detail using the BISICLES ice sheet model, an efficient marine ice sheet model of the latest generation, capable of refinement to kilometre-scale resolution and higher-order ice flow physics. The setup draws on previous efforts to model the deglaciation of the North American Ice Sheet for initialising the ice sheet temperature, recent ice sheet reconstructions for developing the topography of the region and ice sheet, and output from a general circulation model for a representation of the climatic forcing. The modelled deglaciation is in agreement with the reconstructed extent of the ice sheet and the associated meltwater pulse has realistic timing. Furthermore,the peak magnitude of the modelled meltwater equivalent (0.07–0.13 Sv) is compatible with geological estimates of freshwater discharge through the Hudson Strait. The results demonstrate that while improved representation of the glacial dynamics and marine interactions are key for correctly simulating the pattern of early Holocene ice sheet retreat, surface mass balance introduces by far the most uncertainty. The new model configuration presented here provides future opportunities to quantify the range of plausible amplitudes and durations of a Hudson Bay ice saddle collapse meltwater pulse and its role in forcing the 8.2 ka event.

scholarly journals Rapid early Holocene deglaciation of the Laurentide ice sheet

2008 ◽  
Vol 1 (9) ◽  
pp. 620-624 ◽  
Author(s):  
Anders E. Carlson ◽  
Allegra N. LeGrande ◽  
Delia W. Oppo ◽  
Rosemarie E. Came ◽  
Gavin A. Schmidt ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Early Holocene ◽  
Laurentide Ice Sheet
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