35 Ice sheets, glaciers, and landscapes, oh my! (Posters)

Glaciers and ice sheets shaped the landscape of the Northeast. Ice continues to shape the landscape of alpine and polar regions. We welcome submissions on glaciers &  ice sheets of any size, shape, age, and location.

Monday, 23 March 2026
1:30 PM - 5:30 PM
CCC, Ballroom C

Rapid deglaciation of the Laurentide Ice Sheet from the High Peaks Wilderness, Adirondack Mountains, New York, USA during the Allerød Warm Interval

Paper number: 35-4
Program: Technical Sessions
Time: 1:30 PM – 1:30 PM

Authors

Abstract

During the last glacial period, the Laurentide Ice Sheet (LIS) contained 75-85 m of global sea

level equivalent making it the largest ice sheet by volume and a substantial influence within the

climate system. Understanding the timing and rate of LIS deglaciation is of considerable

importance in associating its contribution to sea-level rise, abrupt climate change, and climate

feedbacks. Studies of LIS retreat through the northeast United States have used various

geochronometers (e.g., surface exposure dating, radiocarbon, varves) and methods to constrain

changes in the vertical and lateral components of the ice sheet. Yet, reconstructions of the LIS

in this region exhibit areas of limited geochronologic data leading to assumptions about the

character and timing of ice-sheet retreat. Here we present new 36Cl surface exposure ages from

the High Peaks Wilderness region of the Adirondack Mountains paired with transient ice-sheet

model simulations of LIS retreat through the region. Our results show full retreat of the LIS from

the region occurred within a 500 year interval at 13.5 ± 0.3 ka, consistent with the rate of

deglaciation presented in model simulations through the Adirondacks. The timing of local

deglaciation is younger than previously proposed, while remaining in agreement with

minimum-limiting radiocarbon ages indicating reoccupation of fauna and flora by ~13 cal ka. The

model simulations demonstrate low ice-flow velocities in the mountains relative to the

surrounding lowlands which may have acted as an impediment to ice retreat. These new results

shift the timing of deglaciation from the Adirondack High Peaks later to the Allerød warm interval

with implications for the response time of the ice sheet to abrupt climate warming as well as the

influence of subglacial topography on deglaciation.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411159

© Copyright 2026 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.