Resumen de Datos cronológicos del sistema de terrazas Pleistoceno Medio-Superior en la cuenca del río Gállego (Pirineos-Depresion del Ebro)
Carlos Sancho Marcén, José Luis Peña Monné, Gerardo Benito Ferrández, Claudia J. Lewis, Eric V. McDonald, E. Rhodes
During the Middle-Upper Pleistocene, the Gállego River has developed a complex sequence of stepped terraces with a variety of degradation/aggradational surfaces (cut-in-bedrock, cut-and-fill and nested fill terraces) in response to fluctuations on base level of erosion and water/sediment discharge (climate change driven). A regional sequence composed of ten fluvial levels has been established. At the moment, available chronological data by optically stimulated luminescence suggest the occurrence of three morphosedimentary stages around 30-40, 60-74 and 135-180 ka. The terrace dating and its relation with fluvioglacial sediments point out to cold stages at regional scale with high discharges of water and sediment favouring the alluvial morphogenetic activity along the valley as well as the karstic synsedimentary subsidence in the lower reach
