by Antonio Girona-García, Biodiversity Research Institute (IMIB), CSIC-UniOvi-PA, Mieres, Spain
The visit to the Sorrosal Waterfall is an obligatory stop in your way to the Ordesa National Park, located in the Aragonese Pyrenees (NE-Spain). In the northern area of Huesca province, after a short walk from the town of Broto, this hidden waterfall can be found showing the geomorphological and geological history of the valley.
The Sorrosal Waterfall is located in the confluence of two valleys: Broto Valley, run by the Ara River (nowadays the longest river in the Pyrenees with 67 km) and Sorrosal Valley, a hanging valley 125 m above the position from which this photograph was taken. This waterfall was generated by the combined action of a glacier and the river. During the Ice Age, this site was covered by a 30 km long, 370 m deep glacier that shaped the valley that we nowadays call Broto Valley. At the same time Sorrosal river, fed by a small glacier in its headwaters, carved this valley transversely resulting in the Sorrosal Waterfall.
As a consequence of the slope between the two valleys, an interesting outcrop of geological interest can be observed. The rocks were originated from deep-marine sediments (turbidites) from the Eocene, which suffered a series of stepping folds as a result of the Pyrenees Alpine orogeny, becoming the wavy structure than can be appreciated nowadays.
Antonio Girona-García (distributed via imaggeo.egu.eu)