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| Titel |
New exposure ages for the Last Glacial Cycle in the Sanabria Lake region (northwestern Spain) |
| VerfasserIn |
Laura Rodríguez-Rodríguez, Montserrat Jiménez-Sánchez, María José Domínguez-Cuesta, Vincent Rinterknecht, Raimon Pallàs, Régis Braucher, Didier Bourlès, Blas Valero-Garcés |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072121
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| Zusammenfassung |
| 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.
Cowton, T., Hughes, P.D., Gibbard, P.L., 2009. Palaeoglaciation of Parque Natural Lago
de Sanabria, northwest Spain. Geomorphology 108, 282-291.
Rodríguez-Rodríguez, L., Jiménez-Sánchez, M., Domínguez-Cuesta, M.J.,
Rico, M.T., Valero-Garcés, B., 2011. Last deglaciation in northwestern Spain: New
chronological and geomorphologic evidence from the Sanabria region. Geomorphology 135,
48-65.
Palacios, D., Andrés, N., Úbeda, J., Alcalá, J., Marcos, J., Vázquez-Selem, L., 2012. The
importance of poligenic moraines in the paleoclimatic interpretation from cosmogenic dating.
Geophysical Research Abstracts 14, EGU2012-3759-1.
Pérez-Alberti, A., Valcárcel-Díaz, M., Martini, I.P., Pascucci, V., Andrucci, S., 2011.
Upper Pleistocene glacial valley-junction sediments at Pias, Trevinca Mountains, NW Spain.
In: Martini, I.P., French, H.M., Pérez-Alberti, A. (Eds.), Ice-Marginal and Periglacial
Processes and Sediments. Geological Society (London) Special Publication 354, pp.
93-110.
Research funded by the projects LIMNOCLIBER (REN2003-09130-C02-02),
IBERLIMNO (CGL2005-20236-E/CLI), LIMNOCAL (CGL2006-13327-C04-01)
and GRACCIE (CSD2007-00067) of the Spanish Inter-Ministry Commission of
Science and Technology (CICYT). Additional funding was provided by the Fundación
Patrimonio Natural de Castilla y León through the project “La investigacion en el
Lago de Sanabria dentro del proyecto CALIBRE: perspectivas y posibilidades”,
and by the projects Consolider Ingenio 2006 (CSD2006-0041, Topo-Iberia), 2003
PIRA 00256, HF02.4, and RISKNAT (2009SGR520). L. Rodríguez-Rodríguez has
developed her research under a Severo Ochoa Programme fellowship (FICYT- Asturias). |
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