El de Sanabria es el lago más grande de España con origen glaciar y a la vez se puede considerar el más occidental de todo el Paleártico; dada esta singularidad está considerado como Lugar de Interés Geológico -LIG- por el Instituto Geológico y Minero de España (IGME).
1994
Rodríguez Guitián y Valcárcel, 1994
Contribución al conocimiento del glaciarismo pleistoceno en la vertiente suroocidental del macizo de Peña Trevinca (montañas galaico-sanabrienses, NW Ibérico)
M.A. Rodríguez Guitián y Valcarcel Díaz M.
Se cartografían y describen diversos depósitos y formas de origen glaciar situados en las cabeceras de los ríos Bibei y Xares (Ourense-Zamora). De acuerdo con los datos disponibles, se discute la amplitud y cronología de los fenómenos glaciares que han afectado a la vertiente occidental del macizo de Trevinca-Sanabria durante el último periodo frío.
Enlace: https://investigacion.usc.gal/documentos/5d1df69329995204f7670d47
2007
Rico et al., 2007
El registro sedimentario del Lago de Sanabria desde la última deglaciación
M. Rico, B. Valero Garcés , J.C. Vega, A. Moreno , P. González-Sampériz, M. Morellón y P. Mata
The sedimentary evolution of Sanabria Lake (Zamora province, NW Spain) is reconstructed based on 4 kullenberg cores and 3 short cores. The longest core (9 m long) in the deepest (51 m) eastern subbasin reached the laminated and banded clastic proglacial lacustrine sediments deposited when the watershed was still glaciated. Basal 14C AMS dating (ca. 26 ka BP) indicates that the terminal morraine complex deposited prior to the global LGM. A high resolution study including magnetic susceptibility and XRF core-scanner geochemistry show millennial and century scale cycles in Lateglacial and Holocene organic-rich sediments. Calibration studies including 20 year long series of limnological data, short sediment cores, meteorological and land-use changes data are in progress.
Enlace: http://digital.csic.es/bitstream/10261/38555/1/Páginas%20de%20ContribucionesCuaternario.pdf
2009
Cowton et al., 2009
Palaeoglaciation of Parque Natural Lago de Sanabria, northwest Spain
T. Cowton, P.D. Hughes y P.L. Gibbard
Detailed geomorphological mapping provides evidence for at least three phases of glaciation in the Parque Natural Lago de Sanabria, in northwest Spain. The most extensive glaciation was characterised by a large plateau ice cap. A combination of geomorphological evidence and glacier modelling indicates that this ice cap covered an area of more than 440 km<sup>2</sup>, with a maximum ice thickness of c. 300 m and outlet glaciers reaching as low as 1000 m. This represents the largest ice mass in Iberia outside the Pyrenees and one of the largest in the mountains of southern Europe and the Mediterranean region. Radiocarbon dates from the base of lacustrine sequences appear to suggest that the most extensive phase of ice-cap glaciation occurred during the last cold stage (Weichselian) with deglaciation occurring before 14–15 ka 14C BP. A second phase of glaciation is recorded by the moraines of valley glaciers, which may have drained small plateau ice caps; whilst a final phase of glaciation is recorded by moraines in the highest cirques.
Enlace: http://www.sciencedirect.com/science/article/pii/S0169555X09000671
2011
Rodríguez-Rodríguez et al., 2011
Reconstrucción en 3D del máximo glaciar registrado en la cuenca del Lago de Sanabria (Noroeste de España)
L. Rodríguez-Rodríguez, M. J. Domínguez-Cuesta y M. Jiménez-Sánchez
La realización de una cartografía geomorfológica detallada en una superficie de 220 km2 en torno al Lago de Sanabria (Noroeste de España), junto con la caracterización sedimentológica de los depósitos glaciares, han permitido reconstruir la extensión alcanzada por el hielo durante el máximo glaciar local. De acuerdo con este modelo, el aparato glaciar instalado sobre la cuenca del Lago de Sanabria alcanzó una extensión de al menos 155 km2, situando su frente más avanzado en el valle del Tera (940 m). Sus límites septentrional y oriental habrían sobrepasado los límites de estudio, de modo que este aparato glaciar constituiría una fracción de un casquete montañoso más grande instalado sobre el Macizo de Trevinca, al oeste de la zona de estudio.
Se ha aplicado un modelo matemático para establecer la altitud alcanzada por el hielo a lo largo de 29 perfiles longitudinales siguiendo las paleo-direcciones de flujo del hielo indicadas por las evidencias geomorfológicas. La integración de todos los datos mediante un SIG ha permitido elaborar un modelo digital de la topografía del hielo a partir del cual se ha podido determinar tanto la distribución de potencias del glaciar (entre 0 y 454 m), como su volumen total (estimado en 22,9 km3) durante el máximo glaciar local.
Enlace: http://historia.bio.ucm.es/rsehn/cont/publis/boletines/144.pdf
Rodríguez-Rodríguez et al., 2011
Last deglaciation in northwestern Spain: New chronological and geomorphologic evidence from the Sanabria region
L.Rodríguez-Rodríguez, M. Jiménez-Sánchez, M. J. Domínguez-Cuesta, V. Rinterknecht, R. Pallàs, D. Bourlès y B. Valero-Garcés
Geomorphologic mapping, morphometric analysis of glacial features, and sedimentologic characterization of glacial deposits, together with GIS management, have led to reconstruction of the glacial evolution of the Tera valley glacier (Sanabria Lake basin, NW Spain) after the local glacial maximum. Moreover, a structural analysis of the bedrock fracture network based on a detailed map containing 898 fractures has been used to evaluate the influence of bedrock geology in the development of the glacier pattern. A detailed model of the deglaciation has been constructed by complementing the geomorphologic evidence with the chronological and sedimentologic study of a drilling core retrieved from the eastern subbasin of Sanabria Lake in 2004. According to this model, 10 episodes of glacier front retreat and stabilization took place after the local glacial maximum. Subsequently, a proglacial lake was established in the eastern subbasin of current Sanabria Lake, fed by ablation waters coming from the glacier front retreat. The proglacial activity was extended from a minimum age of 25.6 to 14.3 ka BP, in which the sedimentation of organic-rich muds took place until 13.1 ka BP. Subsequently, around 13.1 to 12.2 ka BP, a short advance of the Tera glacier is inferred from the deposition of coarser and less organic sediments. After this date, the glacier front would have retreated to the headwaters of the Tera valley. Sedimentologic and chronological data from another core retrieved in a moraine-dammed deposit indicate that a marginal lake would have been active since at least 22 ka BP until at least up to 10.5 ka BP to the north of Sanabria Lake. These results suggest a local glacial maximum prior to the global LGM and, therefore, new evidence of an early deglaciation in SW Europe.
Enlace: http://www.sciencedirect.com/science/article/pii/S0169555X11003795
Rodríguez-Rodríguez et al., 2011
LA ÚLTIMA DEGLACIACIÓN EN EL VALLE GLACIAR DEL TERA (LAGO DE SANABRIA, NO ESPAÑA): MODELO EVOLUTIVO
L.Rodríguez-Rodríguez, M. Jiménez-Sánchez, M. J. Domínguez-Cuesta, M. Rico y B. Valero-Garcés
A model for the Tera glacial valley deglaciation (Sanabria Lake, NW Spain): A detailed geomorphological mapping survey combined with sedimentological analyses of two cores in Sanabria and San Martin de Castañeda lakes support the evolution model for the main glacier tongue of the Tera glacier. This glacier tongue would have reached 6.4 km length and 3.9 km width during the local glacial maximum (prior to 26 ka BP). At least 10 episodes of glacial front retreat and stabilization took place subsequently. Then, Sanabria Lake developed as a proglacial lacustrine environment fed by ablation waters from the retreating glacial front. The San Martin de Castañeda marginal proglacial lake formed during the glacial maximum phase and continued as a glaciolacustrine basin behind the north lateral moraine even after the Tera glacier had retreated. The moraine finally broke up resulting in the San Martin landslide formation, the erosion of the glaciolacustrine top unit, and the onset of alluvial sedimentation.
2013
Jiménez-Sánchez et al., 2013
A review of glacial geomorphology and chronology in northern Spain: Timing and regional variability during the last glacial cycle
M. Jiménez-Sánchez, L. Rodríguez-Rodríguez, J.M. García-Ruiz, M.J. Domínguez-Cuesta, P. Farias, B. Valero-Garcés, A. Moreno, M. Rico y M. Valcárcel
In this paper we synthesize the research in glacial geomorphology and geochronology in northern Spain, with special attention to the evidence of local glacier maximum extent earlier than the global LGM of MIS 2 (18–21ka BP). More accurate models of glacier evolution have been defined based on limnogeological, geochronological and geomorphological data. In the Pyrenees, OSL (Optically Stimulated Luminescence), surface exposure and radiocarbon dating techniques have identified end moraines and fluvial terraces corresponding to MIS 6 (about 170ka) and even to MIS 8 (about 260ka), and also established the timing of the last local glacial maxima as prior to global LGM (MIS 4, ca. 50–70ka). During the global LGM a smaller re-advance occurred but glaciers reached different extents in the Central and the Eastern Pyrenees. In NW Iberia, radiocarbon and OSL techniques point to local glacial maximum prior to ca 26ka–38ka and probably synchronous with 45ka. Although some bias might have been introduced by the dating procedures, this review demonstrates that in both regions the local maximum extent occurred prior to the global LGM. The asynchronies between the glacial maxima chronologies in the different mountain ranges of northern Spain suggest that local climate factors exert a strong control on mountain glacier dynamics.
Enlace: https://www.sciencedirect.com/science/article/pii/S0169555X12002930
Rodríguez-Rodríguez et al., 2013
New exposure ages for the Last Glacial Cycle in the Sanabria Lake region (northwestern Spain).
L. Rodríguez-Rodríguez, M. Jiménez-Sánchez, D.Boulés y B. Valero-Garcés
The Sanabria Lake region is located in the Trevinca Massif, a mid-latitude mountain area up to 2128 m asl in the northwest corner of the Iberian Peninsula (42oN 6oW). An ice cap glaciation took place during the Last Glacial Cycle in this massif, with an equilibrium line altitude of 1687 m for the Tera glacial outlet at its local maximum (Cowton et al., 2009). A well preserved glacial sequence occurs on an area of 45 km2 around the present Sanabria Lake (1000 m asl) and is composed by lateral and end moraines in close relationship with glaciolacustrine deposits.
This sequence shows the ice snout oscillations of the former Tera glacier during the Last Glacial Cycle and offers a good opportunity to compare radiocarbon and OSL- based chronological models with new cosmogenic isotope dates.
The new dataset of 10Be exposure ages presented here for the Sanabria Lake moraines is based on measurements conducted on 23 boulders and is compared with previous radiocarbon and OSL data conducted on ice related deposits (Pérez-Alberti et al., 2011; Rodríguez-Rodríguez et al., 2011). Our results are coherent with the available deglaciation radiocarbon chronology, and support a last deglaciation origin for the whole set of end moraines that are downstream the Sanabria Lake (19.2 – 15.7 10Be ka). Discrepancies between results of the different dating methods concern the timing of the local glacial maximum, with the cosmogenic exposure method always yielding the youngest minimum ages. As proposed to explain similar observations made elsewhere (Palacios et al., 2012), reconciling the ages from different dating methods would imply the occurrence of two glacial advances close enough in extent to generate an overlapping polygenic moraine.
2014
Rodríguez-Rodríguez et al., 2014
A multiple dating-method approach applied to the Sanabria Lake moraine complex (NW Iberian Peninsula, SW Europe)
L. Rodríguez-Rodríguez, M. Jiménez-Sánchez, M. J.Domínguez-Cuesta, V. Rinterknecht, R. Pallàs, D. Bourlès y B. Valero-Garcés
New evidence in the NW region of the Iberian Peninsula (∼42°N 6°W) of a glacial advance coeval with the global Last Glacial Maximum (LGM) of the Marine Isotope Stage 2 has been identified through a dataset of exposure ages based on 23 10Be concentration measurements carried out on boulder samples taken from a set of latero-frontal moraines. Results span the interval 19.2–15.4 10Be ka, matching the last deglaciation period when Iberia experienced the coldest and driest conditions of the last 25 ka, and are consistent with Lateglacial chronologies established in other mountain regions from SW Europe. The extent of the LGM stade identified in this work is similar to the local maximum ice extent stade recorded and dated as prior to 33 ka using radiocarbon and optically stimulated luminescence. This work showcases how multiple-dating approaches and detailed geomorphological mapping are required to reconstruct realistic palaeoglacier evolution models.
2016
García-Arias et al., 2016
Geochemical characterization of the leucosomes and leucogranites of the
migmatitic region of Sanabria, Iberian Massif
M. Garcia-Arias, L.G. Corretgé y A. Castro
Leucosomes and leucogranitic bodies are widespread in the migmatitic region of Sanabria, Iberian Massif, Spain, formed during the Variscan orogeny. These leucosomes and leucogranites have a silicic, felsic and peraluminous composition, with low K/Na and Rb/Sr ratios, a linear trend of increasing FeO, MgO and TiO2 with decreasing SiO2, and a highly variable REE and HFSE content that are generally lower than the composition of the source Ollo de Sapo gneiss. The REE and the Eu anomaly in leucosomes are correlated, with stronger positive Eu anomalies with decreasing REE content. The geochemistry of leucosomes and leucogranites is consistent with anatectic melts produced under water-present conditions and with the entrainment of small amounts of accessory-rich biotite. These rocks plot in the volcanic arc granite field instead of the syn-collisional granite field of tectonic discrimination diagrams due to the low Rb content caused by the water-present melting conditions.
Enlace: https://www.researchgate.net/profile/Marcos-Garcia-Arias/publication/308694332
García-Ruiz et al., 2016
Mountain glacier evolution in the Iberian Peninsula during the Younger Dryas
J.M. García-Ruiz, D. Palacios, P. González-Sampériz, N. de Andrés, A. Moreno, B. Valero-Garcés y A. Gómez-Villar
We review the evolution of glaciers in the Iberian Mountains during the Younger Dryas (12.9–11.7 ka, following the chronology of Greenland Stadial 1 – GS1) and compare with available environmental and climate data to investigate glacier dynamics during cold stadial episodes. The best examples of Younger Dryas moraines are found in the Central Pyrenees, involving short ice tongues up to 4 km in length in the highest massifs (above 3000 m a.s.l.) of the southern versant. Small cirque glaciers and rock glaciers formed during the YD occurred in other Pyrenean massifs, in the Cantabrian Range and in the Gredos and Guadarrama sierras (Central Range), as indicated by several rocky, polished thresholds that were ice-free at the beginning of the Holocene. Although some former rock glaciers were re-activated during the Younger Dryas, glacial activity was limited in the southernmost part of the Iberian Peninsula (Sierra Nevada). Most Iberian records show vegetation changes during the YD characterized by a forest decline and an expansion of shrubs (mainly Juniperus) and steppe herbs, although the vegetation response was not homogeneous because of variable resilience among ecosystems. Available records also document a variable lake response in terms of hydrology and productivity, with a decrease in sedimentation rates and organic productivity in most high altitude lakes and increases in salinity and relatively lower lake levels at lower altitudes. The impact of the Younger Dryas on the coastal environment was almost negligible, but it was responsible for a brief cessation in sea level rise. High-resolution analyses of new speleothem records have documented a double structure for the YD with an earlier drier phase followed by a relatively more humid period. The review of geomorphological evidence demonstrates a strong latitudinal control of glacial activity during the YD, with more intense development in the northern than in the southern regions. The increase in humidity during the second phase of the YD in southern latitudes could have been a decisive factor for glacier advance in the northern Iberian mountains.
