Cuaternario y Geomorfología ISSN: 0214-1744 y C G ISSNe: 2695-8589 www.rediris.es/CuaternarioyGeomorfologia/ An exploratory study to test sediments trapped by potholes in Bedrock Rivers as environmental indicators (NW Iberian Massif) Un estudio exploratorio para testar los sedimentos atrapados por marmitas de erosión en ríos sobre roca como indicadores ambientales (NO Macizo Ibérico) Álvarez-Vázquez, M.A. (1); De Uña-Álvarez, E. (1) (1) Department of History, Art and Geography, GEAAT Research Group, Campus of Ourense, University of Vigo. As Lagoas s/n, 32004, Ourense, Spain.
[email protected] Abstract The capacity of fluvial potholes to trap sediments, together with the geochemical analysis of their stored sediments for environmental assessment, is an overlooked research topic in small bedrock rivers. The present exploratory study is focused on this issue. It was developed in a small river over rock, in the inland territory of Galicia (NW Iberian Peninsula). The study started from an analysis of the inventoried fluvial potholes to identify suitable forms for sampling, and the collection of sediment samples within them. After this, the determination of the grain texture, mineralogy and content of major and trace elements in sediments were carried out. Potholes with maximum vertical depth from 25 cm to 1 m, located in central and sidewall sectors of the bedrock channel, provided the best conditions for sediment sampling. The sediments collected from six potholes showed predominance of coarse-medium grain size and sand fraction. The rough contents of the major and even trace elements are related with the nature of the more refractory minerals of the bed- rock.