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- Title
Climatic control on the retreat of the Laurentide Ice Sheet margin in easternmost Québec–Labrador (Canada) revealed by cosmogenic nuclide exposure dating.
- Authors
Couette, Pierre‐Olivier; Ghienne, Jean‐François; Lajeunesse, Patrick; Van der Woerd, Jérôme
- Abstract
The Laurentide Ice Sheet (LIS) was the largest ice sheet in the Northern Hemisphere during the last glacial cycle. The effects of its demise on global climate and sea‐level changes during the subsequent deglaciation are unequivocal. Understanding the interplay between ice sheets and long‐term or short‐term (e.g. abrupt) climatic events is therefore crucial for predicting future rates of ice sheet melting and their potential contribution to sea‐level changes. Here, we present 37 new 10Be surface exposure ages from easternmost Québec–Labrador that allow us to identify close ties between regional deglaciation history and climate. These results reveal that the LIS was disconnected from the Newfoundland Ice Cap by ~14.1 ka. Samples collected from moraine boulders indicate that this event was followed by five major stillstands and/or readvance stages of the LIS margin. Integrating our new moraine ages with those of earlier studies allows us to depict a temporal framework including events at ~12.9, ~11.5, ~10.4, ~9.3 and ~8.4–8.2 ka. These moraine ages highlight a strong sensitivity of the LIS to temperature changes in the Northern Hemisphere, as the documented continental ice margin stabilizations coincide with abrupt cooling events recorded in Greenland ice cores. These observations support the idea of a negative feedback mechanism induced by meltwater forcings into the North Atlantic Ocean which, in turn, provoked repeated cold reversals during the Younger Dryas and early Holocene.
- Subjects
QUEBEC (Quebec); ICE sheets; COSMOGENIC nuclides; ICE sheet thawing; GREENLAND ice; CLIMATE change; ICE cores
- Publication
Journal of Quaternary Science, 2023, Vol 38, Issue 7, p1044
- ISSN
0267-8179
- Publication type
Article
- DOI
10.1002/jqs.3525