Rosa Blanca González-Gutiérrez

Till fabric and grain-size analysis of glacial sequences in the Upper Sil River Basin, Cantabrian Mountains, NW Spain

Fabric and grain-size analysis of eight deposits present in the Upper Sil River Basin palaeoglacial system of northwest Spain were used to interpret till types and to reconstruct the glacial paleoprocess history of this region. They are represented by lodgement, deformation, and melt-out tills. The first, representative of glacial advance stages, present cluster fabrics and are generally composed of poorly sorted and finer sediments. Melt-out and deformation tills, representative of stages of glacial stability followed by fast recession, present transitional to girdle fabrics and are composed of poorly sorted coarser sediments. In any case, multiple criteria, including lithological, clast-shape, or structural data, support these directional and grain-size observations. These sequences, most of them located in the snout area of the Sil palaeoglacier, are important in the reconstruction of glacial dynamics due to poor preservation of landforms related to the maximum glacial advance. This palaeoglacial system was formed by multiple tributaries and had an extension of over 450 km2, with the Sil paleoglacier being 51 km long during its maximum glacial advance.

Glacial cirques in the southern side of the cantabrian mountains of southwestern europe

Abstract A total of 156 glacial cirques located on two different areas in the Cantabrian Mountains (NW Spain) were identified and measured in order to continue and expand the study of these large‐scale erosional forms in European mountains. Environmental variables that may explain cirque distribution (altitude, aspect and lithology), and their most important morphometric features (area, length (L), width (W), headwall height (H), and L/W, L/H and W/H indices), are analysed. Statistical analysis has been applied as indicators of contrast (ANOVA) and association (correlation and regression). Conglomerate analysis (CLUSTER) has been used to discriminate cirque groups based on their morphometric variables. Results show that cirques occur at lower altitudes in the Upper Sil River basin area than in the Montaña Central area due to a lower former equilibrium line altitude (ELA) position. In the Upper Sil River basin, environmental variables appear to have had a strong influence on the location and size of cirques: the largest cirques are located in quartzite rocks at elevations above 2000 m and face N or NE. In Montaña Central, the influence of these factors was more limited as a consequence of higher geological structure control. Cirque sizes generally are modest compared with cirques present in other mountain ranges globally, most likely due to shorter glacial occupancy in the Cantabrian Mountains.

Geomorphology of the Curueño River headwaters, Cantabrian mountains (NW Spain)

ABSTRACT The article presents the 1:25,000-scale geomorphological map of the upper reaches of the Curueño River, on the southern slope of the Central Cantabrian Mountains, NW Spain. The study area spans approximately 125 km2 and corresponds to the 1:25,000-scale Spanish National Topographical Map Sheet 104-I of Lugueros. The area is moderately mountainous with elevation ranging from 1100 to 2100 m.a.s.l. The main landforms are river gorges, karst, and glacial landforms. The map legend contains 78 elements divided into 9 groups: litho-structural, polygenic, karst, fluvial, glacial, periglacial, nival, gravitational, weathering, and anthropic forms. The map was prepared using Esri ArcGIS with the Universal Transverse Mercator (UTM, Zone 30) projection. In addition, a database and style set were created for each landform with the goal of using this set of symbols in other areas and performing complementary mapping of geologic and geomorphologic risk, protection of natural geoheritage, land-use classification, and applied geomorphology.

La Balouta exhumed karst: a Roman gold-mine-derived landscape within the Las Médulas UNESCO World Heritage Site (Spain)

This study examines a paleokarst exhumed as a result of mining operations conducted by the Ancient Romans in the recovery of gold contained in Cenozoic sediment that previously covered the ancient karstic formations. Paleokarsts-related sedimentary deposits containing valuable mineral substances such as iron ores, bauxite, lead ores, precious stone deposits (Bosák, 1989) or gold (i.e., in the Urals (Filippov, 2006)) have been mined in many parts of the world. Known cases in the Iberian Peninsula have also shown that ancient mining operations coincided with areas of ancient karstification. For example, the Romans mined iron in Cerro del Hierro (Miras Ruiz & Galán Citation: