The glaciers in the Redes Natural Park

The Redes Natural Park is located in the southeastern sector of the Principality of Asturias (43° 13′ N, 4° 58′ W). Most of its territory (378 km 2 ) falls within the headwaters of the Nalón River, one of the main rivers on the northern slopes of the Cantabrian Mountains. The glacial landforms, discovered toward the latter half of the 20th century, include 62 glacial cirques (ranging in altitude from 1500 m to greater than 2000 m), accumulations (reaching altitudes of 930–1700 m), and other associated landforms. The development and conservation of the glacial morphology are influenced by several factors, most notably the lithological composition of the bedrock and its tectonic configuration, which in turn condition other slope parameters, such as the altitude, orientation, and inclination. Twenty-two glaciers existed in the Redes Natural Park during the maximum local glacial advance, occupying a total surface area of c. 41 km 2 . The maximum glacial advance would have taken place prior to 33.5 ka cal BP, perhaps with a later retreat. However, we interpret that the ice would have advanced by 24 ka, to then retreat at least between 18.1 and 14 ka. Subsequently, periglacial conditions would have prevailed (toward 13 ka), as indicated by the presence of rock glaciers. The subsequent action of the ice and snow is mainly marked by névé moraines, whose age is unknown. With regard to these ages, the area constitutes a reference locality from the geomorphological and geochronological points of view, specifically on account of the data obtained in the Monasterio River Valley.