Artículos de revistas
Climatic controls on debris-flow activity and sediment aggradation: The Del Medio fan, NW Argentina
Fecha
2016-12Registro en:
Savi, Sara; Schildgen, Taylor F.; Tofelde, Stefanie; Wittmann, Hella; Scherler, Dirk; et al.; Climatic controls on debris-flow activity and sediment aggradation: The Del Medio fan, NW Argentina; Wiley; Journal of Geophysical Research: Earth Surface; 121; 12; 12-2016; 2424-2445
2169-9003
2169-9011
CONICET Digital
CONICET
Autor
Savi, Sara
Schildgen, Taylor F.
Tofelde, Stefanie
Wittmann, Hella
Scherler, Dirk
Mey, Jürgen
Alonso, Ricardo Narciso
Strecker, Manfred R.
Resumen
In the Central Andes, several studies on alluvial terraces and valley fills have linked sediment aggradation to periods of enhanced sediment supply. However, debate continues over whether tectonic or climatic factors are most important in triggering the enhanced supply. The Del Medio catchment in the Humahuaca Basin (Eastern Cordillera, NW Argentina) is located within a transition zone between subhumid and arid climates and hosts the only active debris‐flow fan within this intermontane valley. By combining 10Be analyses of boulder and sediment samples within the Del Medio catchment, with regional morphometric measurements of nearby catchments, we identify the surface processes responsible for aggradation in the Del Medio fan and their likely triggers. We find that the fan surface has been shaped by debris flows and channel avulsions during the last 400 years. Among potential tectonic, climatic, and autogenic factors that might influence deposition, our analyses point to a combination of several favorable factors that drive aggradation. These are in particular the impact of occasional abundant rainfall on steep slopes in rock types prone to failure, located in a region characterized by relatively low rainfall amounts and limited transport capacity. These characteristics are primarily associated with the climatic transition zone between the humid foreland and the arid orogen interior, which creates an imbalance between sediment supply and sediment transfer. The conditions and processes that drive aggradation in the Del Medio catchment today may provide a modern analog for the conditions and processes that drove aggradation in other nearby tributaries in the past.