Cíes Islands: a wind trap in the Ria of Vigo (Galicia, Spain) at the end of the Last Glacial

• Main Authors: Arce Chamorro, Carlos, Vidal Romaní, Juan Ramón, Sanjurjo Sánchez, Jorge
• Format: Article in Journal/Newspaper
• Language: Spanish
• Published: Sociedad Geológica de España 2021
• Subjects: coastal eolianites; OSL-dating; upper pleistocene; glacio-eustasy; Cies Islands; Galicia (NW of Spain); eolianitas costeras; datación OSL; glacio-eustasia; Islas Cíes; Galicia (N.O. de España); Pleistoceno Superior; Islas Cíes: una trampa eólica al final del último glacial; Duna; North Atlantic
• Online Access: https://recyt.fecyt.es/index.php/geogaceta/article/view/102257

Cies Islands have been an obstacle to the intense coastal winds from the North Atlantic, especially during the Quaternary glacial cycles. At the end of the Last Glacial period, the local sedimentary-record shows that sea-level decreased more than 100 m below present level. This sea-level drop transformed the archipelago into an emerged relief 300 m high, which probably deflected the wind and, at the same time, was able to capture aeolian sediments coming from a strip of the continental shelf also emerged. Under this hypothesis, these aeolian materials were deposited covering the contour of Cies Islands. An example of these aeolian accretion processes is the eolianites outcrop located at Monteagudo Island (Cies Islands, Galicia, Spain) interpreted as a climbing-dune which was active from the end of the Upper Pleistocene, partially covering the eastern slope. This deposit more than 3 meters thick with an OSL age of 35 ky (b2k) at the base and 17 ky at the top, is an evidence of the aeolisation developed in the Galician coast for thousands of years, finally disrupted when aeolian-supplies were suspended during Holocene post-glacial. Las Islas Cíes han constituido un obstáculo para los intensos vientos costeros del Atlántico Norte, especialmente durante las fases glaciares del Cuaternario. Al final del último glaciar el mar descendió más de 100 m por debajo de su nivel actual. Este descenso transformó el archipiélago en un relieve emergido de 300 m de alto, capaz de deflectar el viento y atraer, al mismo tiempo, sedimentos eólicos procedentes de una franja de plataforma continental también emergida. Bajo esta hipótesis, estos materiales eólicos se depositaron cubriendo el contorno de Cíes. Un ejemplo de estos episodios de acreción eólica es el afloramiento de eolianitas situado en la Isla de Monteagudo (Islas Cíes, Galicia, España), interpretado como una duna rampante que estuvo activa desde el final del Pleistoceno Superior, cubriendo parcialmente la vertiente oriental. Con un espesor de más de 3 metros y una ...