Transient sediment supply in a high‐altitude Alpine environment evidenced through a 10Be budget of the Etages catchment (French Western Alps). Issue 7 (25th November 2013)

• Record Type: Journal Article
• Authors: Delunel, Romain; van der Beek, Peter A.; Bourlès, Didier L.; Carcaillet, Julien; Schlunegger, Fritz
• Is Part Of: Earth surface processes and landforms. Volume 39:Issue 7(2014)
• Page Start: 890
• Page End: 899
• Publication Date: 2013-11-25
• Subjects: Geomorphology -- Periodicals; 551.4
• DOI: 10.1002/esp.3494
• Languages: English
• ISSNs: 0197-9337

Abstract

<abstract abstract-type="main"> <title>ABSTRACT</title> <p>Although beryllium‐10 (<sup>10</sup>Be) concentrations in stream sediments provide useful synoptic views of catchment‐wide erosion rates, little is known on the relative contributions of different sediment supply mechanisms to the acquisition of their initial signature in the headwaters. Here we address this issue by conducting a <sup>10</sup>Be‐budget of detrital materials that characterize the morphogenetic domains representative of high‐altitude environments of the European Alps. We focus on the Etages catchment, located in the Ecrins‐Pelvoux massif (southeast France), and illustrate how <italic>in situ</italic><sup>10</sup>Be concentrations can be used for tracing the origin of the sand fraction from the bedload in the trunk stream. The landscape of the Etages catchment is characterized by a geomorphic transient state, high topographic gradients, and a large variety of modern geomorphic domains ranging from glacial environments to scarcely vegetated alluvial plains. Beryllium‐10 concentrations measured in the Etages catchment vary from ~1 × 10<sup>4</sup> to 4.5 × 10<sup>5</sup> atoms per gram quartz, while displaying consistent <sup>10</sup>Be signatures within each representative morphogenetic unit. We show that the basic requirements for inferring catchment‐wide denudation from <sup>10</sup>Be concentration measurements are not satisfied in this small, dynamic catchment. However, the distinct <sup>10</sup>Be signature observed for the geomorphic domains can be used as a tracer. We suggest that a terrestrial cosmogenic nuclide (TCN) budget approach provides a valuable tool for the tracing of material origin in basins where the 'let nature do the averaging' principles may be violated. Copyright © 2013 John Wiley & Sons, Ltd.</p> </abstract>