Contribution on understanding sediment alteration in an Alpine catchment; lithology matters!

Abstract

Sediment transport in rivers is a complex process whose understanding is still partial. Each sediment particle can be characterized by its size, shape or distance it travelled from its entrance into the river network to its actual position on the river bed. A number of field techniques have been developed to estimate sediment source locations. This research investigates the possibility of using sediment morphometry as a proxy for travel distance. Recent studies on sediment attrition claim the existence of a “universal” relation between particles’ mass loss and specific shape indices. In order to test this hypothesis, we identified a small basin with localized sources of arenites and metabasalts, which we treated as tracers. We identified lithology as a major control on the absolute attrition speed, while downstream trends in shape changes are controlled by sediment production at basin scale.