Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles

Mair, David; Lechmann, Alessandro; Yeșilyurt, Serdar; Tikhomirov, Dmitry; Delunel, Romain; Vockenhuber, Christof; Akçar, Naki; Schlunegger, Fritz

doi:10.1038/s41598-019-46969-0

Cited by 13 publications

(28 citation statements)

References 74 publications

(142 reference statements)

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“…CC BY 4.0 License. (Mair et al, 2019). The new site EW-01, however, hosts bedrock with significant quartz content.…”

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 98%

“…1) and on the NW bedrock flanks of the Eiger (sites EW-02 and EW-03, Figs. 1, 2;Mair et al, 2019). On the NW flank, the EW-03 site is located in the footwall segment at an elevation of 2530 m.a.s.l, whereas site EW-02 is situated near the base of the upper, nearly vertical segment at an elevation of 2803 m a.s.l.…”

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

“…On the SW side, denudation rates range between 150 and 250 cm kyr -1 (sites EM-01 and EM-02). Mair et al (2019) used these rates together with the relatively large concentration of cosmogenic 36 Cl at greater depths in the depth profiles to propose a model where denudation of the rock face has been accomplished by frequent, cm-scale rock fall processes together with chemical dissolution of limestone. We benefit from the results of this previous study and complement the denudation dataset with cosmogenic nuclide data of a further depth profile EW-01.…”

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

“…This is the reason why for this site, we prepared samples for the analysis of in-situ 10 Be instead. Similar to Mair et al (2019), bedrock samples were collected along the walls of a construction tunnel that connect the Jungfraubahnen railway tunnel with the headwall surface of the Eiger. These tunnels were used to depose material during tunnel construction between 1896 and 1905 AD.…”

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

“…We used the combination of these constraints to calculate a total site-specific shielding factor ( ) and apparent attenuation length ( Λ , ) for spallogenic particles with the CRONUS Earth online Topographic Shielding Calculator v2.0 (Marrero et al, 2016). The shielding factor ( ) was used to correct for both spallogenic and muogenic production, which is necessary due to the large height of the headwall (Mair et al, 2019). The https://doi.org/10.5194/esurf-2019-56 Preprint.…”

Section: Scaling and Corrections For Muogenic Productionmentioning

confidence: 99%

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The role of frost cracking in local denudation of steep Alpine headwalls over millennia (Mt. Eiger, Switzerland)

Mair¹,

Lechmann²,

Delunel³

et al. 2019

Preprint

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Abstract. Denudation of steep headwalls is driven by rock fall processes of various size and magnitude. They are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, thus pre-conditioning rock fall. However, these controls and conditions thereof on the denudation processes operating on steep headwalls have remained debated. In this study, we link new and published long-term headwall denudation rate data for the Eiger Mountain in the Central Swiss Alps with the local bedrock fabric and the temperature conditions at these sites, which depend on the insolation pattern. We then estimate the tendency of bedrock for failure through the employment of a theoretical frost cracking model, which bases on the reconstructed temperature conditions. The results show that the denudation rates are low in the upper NW headwall compared to the high rates both on the NW footwall and on the SE face, despite similar bedrock fabric conditions. For these sites, the frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper NW headwall, but relatively large on the lower footwall of the NW wall and on the SE flank of the Eiger. We explain this pattern by the differences in insolation and local temperature conditions. These contrasts might be enhanced by permafrost occurrence in the upper NW wall, which would further reduce cracking efficiency. Throughout the last millennium, conditions have been very similar to the present temperatures in bedrock. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation, which explain the relatively low denudation rates in the upper NW headwall of the Eiger, but the rapid denudation in the SW side and NW footwall of the Eiger where frost cracking is more efficient.

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“…CC BY 4.0 License. (Mair et al, 2019). The new site EW-01, however, hosts bedrock with significant quartz content.…”

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 98%

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

Section: Geomorphology and Cosmogenic Sampling Sitesmentioning

confidence: 99%

Section: Scaling and Corrections For Muogenic Productionmentioning

confidence: 99%

See 3 more Smart Citations

The role of frost cracking in local denudation of steep Alpine headwalls over millennia (Mt. Eiger, Switzerland)

Mair¹,

Lechmann²,

Delunel³

et al. 2019

Preprint

Self Cite

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Temporal evolution of headwall erosion rates derived from cosmogenic nuclide concentrations in the medial moraines of Glacier d'Otemma, Switzerland

Wetterauer

Scherler

Anderson

et al. 2022

Earth Surf Processes Landf

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Climate change affects the stability and erosion of high‐alpine rock walls above glaciers (headwalls) that deliver debris to glacier surfaces. Since supraglacial debris in the ablation zone alters the melt behaviour of the underlying ice, the responses of debris‐covered glaciers and of headwalls to climate change may be coupled. In this study, we analyse the beryllium‐10 (10Be)‐cosmogenic nuclide concentration history of glacial headwalls delivering debris to the Glacier d'Otemma in Switzerland. By systematic downglacier‐profile‐sampling of two parallel medial moraines, we assess changes in headwall erosion through time for small, well‐defined debris source areas. We compute apparent headwall erosion rates from 10Be concentrations ([10Be]), measured in 15 amalgamated medial moraine debris samples. To estimate both the additional 10Be production during glacial debris transport and the age of our samples we combine our field‐based data with a simple model that simulates downglacier debris trajectories. Furthermore, we evaluate additional grain size fractions for eight samples to test for stochastic mass wasting effects on [10Be]. Our results indicate that [10Be] along the medial moraines vary systematically with time and consistently for different grain sizes. [10Be] are higher for older debris, closer to the glacier terminus, and lower for younger debris, closer to the glacier head. Computed apparent headwall erosion rates vary between ~0.6 and 10.8 mm yr−1, increasing over a maximum time span of ~200 years towards the present. As ice cover retreats, newly exposed headwall surfaces may become susceptible to enhanced weathering and erosion, expand to lower elevations, and contribute formerly shielded bedrock of likely different [10Be]. Hence, we suggest that recently lower [10Be] reflect the deglaciation of the debris source areas since the end of the Little Ice Age.

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Late-Pleistocene catchment-wide denudation patterns across the European Alps

Delunel

Schlunegger

Valla

et al. 2020

Earth-Science Reviews

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Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles

Cited by 13 publications

References 74 publications

The role of frost cracking in local denudation of steep Alpine headwalls over millennia (Mt. Eiger, Switzerland)

The role of frost cracking in local denudation of steep Alpine headwalls over millennia (Mt. Eiger, Switzerland)

Temporal evolution of headwall erosion rates derived from cosmogenic nuclide concentrations in the medial moraines of Glacier d'Otemma, Switzerland

Late-Pleistocene catchment-wide denudation patterns across the European Alps

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