IGEBA   23946
INSTITUTO DE GEOCIENCIAS BASICAS, APLICADAS Y AMBIENTALES DE BUENOS AIRES
Unidad Ejecutora - UE
capítulos de libros
Título:
Novel cosmogenic datings in landslide deposits, San Juan, Argentina
Autor/es:
JEANNERET, P; BINNIE, S; BOURLÈS, D.; MOREIRA, S; - ORGEIRA, M.J.; KEDDADOUCHE, K; GAERTNER, A; AUMAÎTRE, G.
Libro:
Fifth World Landslide Forum
Editorial:
Elsevier
Referencias:
Año: 2020; p. 1 - 18
Resumen:
High-mountain environments in an active tectonic setting are prone to landsliding. Thetriggering mechanisms can vary, as these areas are influenced by several pre-conditioningfactors coupled with active seismicity and climatic forcings. Understanding the intrinsic andexternal mechanisms by which these events are influenced would help to establish betterconstraints onto their timing and periodicity and, eventually, hazard assessment and prediction.Glacially eroded valleys are especially prone as they deeply incise mountain ranges leavingunstable slopes once they retreat. Establishing the timing of such events enables betterunderstanding of the triggering and pre-conditioning factors of landslides. To this aim, 10 Be and26 Al cosmogenic age determinations were performed in three landslide deposits in a poorlystudied area of San Juan province, all of which are novel to the area. Coupled with remotesensing techniques, field observations and detailed stratigraphic and sedimentological studies,these new large landslides represent a first approach to understand this dynamic environment.The three landslides were categorized as rock avalanches found in the middle and lowerreaches of the Blanco River, sourced from the Choiyoi Group with evidence of hydrothermalalteration and including/deforming moraine deposits during their fall. Ages are 20.9±1.4,10.8±0.7 and 12.8±0.9 ka from the lowermost deposit to the highest, respectively. Even thoughone sample per deposit is not enough to have statistically significant exposure ages, thesevalues, along with the established chronostratigraphy, allow first order interpretations regardingthe links between deglaciation processes and readjustment of the slopes via large landslideevents.