Quantification of post-glacier bedrock surface erosion in the European Alps using¹⁰Be and optically stimulated luminescence exposure dating

Abstract

Abstract. The retreat of glaciers since the Last Glacial Maximum in the European Alps has left an imprint on topography through various erosional processes. However, few methods are currently capable of resolving these mechanisms on Late Glacial to Holocene timescales. Quantifying the relative contributions of mountain erosion, during these different climate cycles, is useful for understanding long-term landscape evolution and the links between global climate and erosion. Here, we combine three optically stimulated luminescence (OSL) exposure dating signals with 10Be surface exposure dating to constrain the post-glacier erosion rates of bedrock samples adjacent to the Gorner Glacier in the European Alps. The results reveal erosion rates of the order of 10−2 to 10−1 mm a−1, in general agreement with other studies in the region, as well as a strong negative correlation between erosion rate and elevation, suggesting that frost crack weathering is perhaps not the dominant form of post-glacier weathering. Finally, a global compilation of both subglacial and periglacial erosion rates shows that periglacial erosion rates could be greater than previously thought. Yet subglacial erosion remains higher, implying that it continues to have the stronger influence on shaping landscapes. Therefore, with a changing climate, periglacial erosion rates are likely to remain transient. These insights could lead to important implications for landscape evolution models.

Elevation‐Dependent Periglacial and Paraglacial Processes Modulate Tectonically‐Controlled Erosion of the Western Southern Alps, New Zealand

“…To our knowledge, previous catchment‐averaged denudation rates attributed to peri‐ or paraglacial bedrock erosion are <2 mm/yr, with spatial or temporal denudation‐rate differences within a factor of 3 (Delunel et al., 2010; Marshall et al., 2015). Most rockwall erosion‐rate estimates related to peri‐ and paraglacial erosion are also <2 mm/yr (Draebing et al., 2022; Elkadi et al., 2022; Hartmeyer et al., 2020b). The only exceptions are a few faster estimates derived from single rockwalls over periods of a few years (Draebing et al., 2022), which may not be representative of landscape‐scale erosion over longer timescales.…”

Quantification of post-glacier erosion in the European Alps using 10Be and OSL exposure dating

“…Data availability. The dataset can be accessed using the following DOI: https://doi.org/10.5281/zenodo.7038427 (Elkadi et al, 2022).…”