Influencia de la subsidencia por disolución de la Formación Yesos de Barbastro en la evolución del sistema fluvial del Río Noguera Ribagorzana (Cuenca del Ebro)

Within the halite-bearing evaporitic core of the Barbastro Anticline, the deposits of certain terraces of the Noguera Ribagorzana River and its tributary the Lo Reguer Creek are locally thickened. The terrace T9 of the Noguera Ribagorzana (+176-161 m above the present thalweg) reaches 110 mand the alluvium of terraces T5 (+92-50 m) and T3 (+59-49 m) of Lo Reguer Creek reaches 100 and50 m respectively. These anomalous thickenings, restricted to areas underlain by evaporitc bedrock, are attributed to a synsedimentary dissolution-induced subsidence phenomenon, reported for the first time in the Barbastro Anticline. The sedimentological changes observed in the thickened fluvial deposits (high proportion of fine-grained facies) and the development of degradation alluvial surfaces are also related to the evaporite dissolution subsidence phenomena.