1,2,2,7,8,1,9- 1Heidelberg University, Institute of Environmental Physics, Physics, Heidelberg, Germany
- 2Kirchhoff-Institute for Physics, Heidelberg University, Heidelberg, Germany
- 3Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Venice, Italy
- 4Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany
- 5Goethe University Frankfurt am Main, Frankfurt am Main, Germany
- 6Institute for Interdisciplinary Mountain Research of the Austrian Academy of Sciences, Innsbruck, Austria
- 7PSI Center for Energy and Environmental Sciences, Villigen PSI, Switzerland
- 8Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
- 9Heidelberg Center for the Environment, Heidelberg University, Heidelberg, Germany
In the wake of a warming global climate, prolonged periods of negative mass balance affect even high-altitude Alpine glaciers. For these ideal candidates for paleoclimate-related ice core studies, this greatly complicates the already challenging task of establishing an age-depth relationship, because both the age at depth and at the surface is unknown. Radiometric ice dating methods are an important key to overcome this challenge. For Alpine glaciers that have already lost significant amounts of surface ice, the combined use of the radiometric tracers 39Ar and 14C has proven to be particularly effective (Legrand et al., 2025, Hou et al., 2025, Wachs et al., 2026).
Among other applications, we will present a recently published (Wachs et al., 2026) study on the age-depth profile of the summit glacier of Weißseespitze (WSS, 3500 m a.s.l.) in the Austrian Alps. All 39Ar samples were measured using atom trap trace analysis (ATTA), while 14C data from an earlier publication (Bohleber et al., 2020) complete the record. Constrained by the measurements, age modeling using least squares fitting and Monte Carlo sampling was performed to find a suitable glaciological model and to establish a continuous age-depth relationship.
The results show that the surface ice at WSS dates back approximately 400 years, emphasizing the extent of recent ice loss. At the same time, the continuous age-depth relationship shows no evidence of prolonged periods of mass loss at WSS within the 6000 years glaciation history prior to the present. The resulting age–depth relationship thus forms the basis for the historical interpretation of chemical records from WSS, such as recently published by Spagnesi et al., 2026, and their intercomparison with other paleoclimate archives.
Beyond WSS, the combined 39Ar-14C dating approach is readily transferable to other vulnerable Alpine ice archives. We will discuss ongoing work at sites such as Jamtalferner and others and illustrate its potential to establish robust chronologies across a range of Alpine glacial settings.
Bohleber et al., New glacier evidence for ice-free summits during the life of the Tyrolean Iceman, Scientific Reports, 2020
Hou et al., A radiometric timescale challenges the chronology of the iconic 1992 Guliya ice core, Science Advances, 2025
Legrand et al., Alpine ice core record of large changes in dust, sea-salt, and biogenic aerosol over Europe during deglaciation, PNAS Nexus, 2025
Spagnesi et al., New chemical signatures from Weißseespitze ice cores (Eastern Alps): pre-industrial pollution traces from Roman Empire to Early Modern Period, Frontiers in Earth Science, 2026
Wachs et al., A continuous 6000 year age depth relationship for the remainder of the Weißseespitze summit glacier based on 39Ar and 14C dating, Climate of the Past, 2026
How to cite: Wachs, D., Spagnesi, A., Bohleber, P., Fischer, A., Stocker-Waldhuber, M., Junkermann, A., Mandaric, N., Meienburg, F., Jenk, T., Oberthaler, M., and Aeschbach, W.: 39Ar and 14C on ice - Dating the remainders of Alpine glaciers amid rapid mass loss, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19191, https://doi.org/10.5194/egusphere-egu26-19191, 2026.
