Marine‐Calibrated Chronology of Southern Laurentide Ice Sheet Advance and Retreat: ∼2,000‐Year Cycles Paced by Meltwater–Climate Feedback
Abstract
Climatic warming following the Last Glacial Maximum caused the southern Laurentide Ice Sheet (LIS) to begin ∼2,000‐year cycles of retreat and readvance whose cause remains ambiguous. By developing a marine‐calibrated chronology of southern LIS position, we counterintuitively demonstrate that between 17.6 and 11.3 ka, ice advanced during times of northern‐hemisphere warming and retreated during times of northern‐hemisphere cooling. Here we propose a cyclical feedback: Meltwater from ice retreat cooled the northern hemisphere by weakening the Atlantic Meridional Overturning Circulation (AMOC). This eventually lead to ice‐sheet readvance, which reduced and rerouted meltwater discharge, and thereby allowed the AMOC to strengthen and the northern hemisphere to warm. Our data suggest that this antiphased ice–climate interaction, paced by ice‐sheet response time, was initiated by synchronous warming and ice retreat ∼18.7–17.6 ka (corresponding to the Erie “Interstade”) and reached its apex during the Younger Dryas.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- May 18, 2023
- Source ID
- 10.1029/2022gl100391
Entities
People
- Andrew D. Wickert
- Carlie Williams
- Carrie E. Jennings
- Kerry L. Callaghan
- Lael Vetter
- Lauren J. Gregoire
- Paul J. Valdes
- Ruza F. Ivanovic
Organizations
- Alexander von Humboldt Foundation
- Columbia University
- McKnight Foundation
- National Science Foundation
- United States Department of Defense
- University of Arizona
- University of Bristol
- University of Illinois Urbana–Champaign
- University of Leeds
- University of Minnesota
- University of South Florida