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

Mair, David; Lechmann, Alessandro; Yesilyurt, Serdar; Tikhomirov, Dmitry; Delunel, Romain; Vockenhuber, Christof; Akçar, Naki; Schlunegger, Fritz (2019). Fast long-term denudation rate of steep alpine headwalls inferred from cosmogenic 36Cl depth profiles. Scientific Reports, 9(1), p. 11023. Nature Publishing Group 10.1038/s41598-019-46969-0

Preview

Text Mair_et_al-2019-Scientific_Reports.pdf - Published Version Available under License Creative Commons: Attribution (CC-BY). Download (3MB) | Preview

Quantifications of in-situ denudation rates on vertical headwalls, averaged over millennia, have been thwarted because of inaccessibility. Here, we benefit from a tunnel crossing a large and vertical headwall in the European Alps (Eiger), where we measured concentrations of in-situ cosmogenic 36Cl along five depth profiles linking the tunnel with the headwall surface. Isotopic concentrations of 36Cl are low in surface samples, but high at depth relative to expectance for their position. The results of Monte-Carlo modelling attribute this pattern to inherited nuclides, young minimum exposure ages and to fast average denudation rates during the last exposure. These rates are consistently high across the Eiger and range from 45 ± 9 cm kyr−1 to 356 ± 137 cm kyr−1 (1σ) for the last centuries to millennia. These high rates together with the large inheritance point to a mechanism where denudation has been accomplished by frequent, cm-scale rock fall paired with chemical dissolution of limestone.

Interest & Impact

Downloads

159 since deposited on 06 Aug 2019
29 in the past 12 months

Citations

5 Citations in Web of Science ®
6 Citations in Scopus

Search

in Google Scholar™

Services

Actions (login required)

Edit item

Actions (login required)

Edit item