We used concentrations of in situ cosmogenic10Be from riverine sediment to quantify the basin‐averaged denudation rates and sediment fluxes in the Plessur Basin, Eastern Swiss Alps, which is a tributary stream to the Alpine Rhine, one of the largest streams in Europe. We complement the cosmogenic dataset with the results of morphometric analyses, geomorphic mapping, and sediment fingerprinting techniques. The results reveal that the Plessur Basin is still adjusting to the landscape perturbation caused by the glacial carving during the Last Glacial Maximum c. 20,000 years ago. This adjustment has been most efficient in the downstream part where the bedrock comprises high erodibility North Penninic flysch and Bündnerschist, whereas glacial land-forms are still prominently preserved in the upstream region, comprising low erodibility South Penninic and Austroalpine bedrock. This geomorphic observation is supported by the10Be based denudation rate and sediment provenance analysis, which indicate a much faster sediment production in the flysch and schist lithologies. Interestingly, the reach of fast denudation has experienced the highest exhumation and rock uplift rates. This suggests that lithologic and glacial conditioning have substantially contributed to the local uplift and denudation as some of the driving forces of a positive feedback system.
Bibliographical noteFunding Information:
Funding: This research was funded through various grants offered by the University of Bern, with major contributions by the Swiss National Science Foundation (project 147689 awarded to Fritz Schlunegger) and some support from the European Union’s Horizon 2020 research and innovation programme under the Marie Sklodowska‐Curie grant agreement No 860383 (awarded to Ronald van Balen).
© 2021 by the authors. Licensee MDPI, Basel, Switzerland.
- Cosmogenic nuclides
- Geomorphometric analysis
- Positive feedback
- Prättigau half‐window
- Sediment fingerprinting