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80-3 An assessment of the use of dipstick studies to constrain ice-sheet thinning in the Adirondack Mountains, NY, USA

Session: Recent Advances in Glacial Geology, Geomorphology, and Chronology

Presenting Author:

Aaron Barth

Authors:

Barth, Aaron M.¹, Barker, Kelsey², Cuzzone, Joshua K.³, Hidy, Alan⁴

(1) Geology, Rowan University, Glassboro, New Jersey, USA, (2) Geology, Rowan University, Glassboro, New Jersey, USA, (3) Joint Institute for Regional Earth System Science and Engineering, University of California, Los Angeles, Los Angeles, California, USA, (4) Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, California, USA,

Abstract:

Reconstructions of paleo-ice sheets provide a valuable resource when determining the sensitivity of ice sheets and sea-level rise to anthropogenic climate change. While the geologic record is abundant with records of ice-sheet margin changes permitting detailed reconstructions of how the ice sheet retreated throughout the last deglaciation, fewer data are available for constraining changes in the ice-sheet surface. In an effort to place limits on vertical variability in the ice sheet, studies have measured surface exposure ages of boulders and bedrock along vertical transects colloquially known as dipstick studies. In a first-order interpretation, these data provide geologic constraints on the location of the ice sheet surface as it thinned during deglaciation. However, numerous areas exist to challenge these interpretations including insufficient erosion under cold-based ice at high elevations leading to nuclide inheritance, and characterization of the mechanisms leading to changes in the ice-surface elevation (e.g., top-down ablation vs. margin retreat). Here we present a case study in the Adirondack Mountains of New York, USA where 36Cl surface exposure ages and numerical ice-sheet modeling simulations reinterpret the deglacial history of the region with full deglaciation of the High Peak Wilderness occurring 13.5 ± 0.3 ka through rapid (~500 years) retreat of the Laurentide Ice Sheet. Discussion is given to the influence of polythermal ice and nuclide inheritance and current attempts to quantify its influence on exposure ages. Results of these findings suggest special attention be given to regional subglacial topography, ice-flow dynamics, and thermal regime when considering the interpretation of dipstick studies in the venue of recording ice-sheet thinning.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10753

An assessment of the use of dipstick studies to constrain ice-sheet thinning in the Adirondack Mountains, NY, USA

Description

Session Format: Oral

Presentation Date: 10/20/2025

Presentation Start Time: 08:45 AM

Presentation Room: HBGCC, 213AB

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