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Reconstrucción y cronología del glaciar de meseta de la Sierra de Béjar (Sistema Central Español) durante el máximo glaciar

Carrasco, R.M., Villa, J., Pedraza, J., Domínguez-Villar, D., Willenbring, J.K.
2 011
Bol. R. Soc. Esp. Hist. Nat. Sec. Geol.
During the last glaciation (Late Pleistocene) Sierra de Béjar hosted a plateau glacier with two morphologies: a plateau icefield and a Plateau icecap. The former developed in the southern sector and was formed by a set of valley glaciers coalescent in the upper sectors. The later occupied the northern sector of the range, being a non-confined dome-shaped ice mass, which was favoured by the plateau morphology of the bedrock. The detailed study of the glacier morphology in Sierra de Béjar has conducted to identify reliable indicators to reconstruct the ice masses during the Glacial Maximum (MG). These indicators were used to calculate different morphologic, dynamic and chronologic paramenters, very useful in unravelling the glacier evolution and to extract paleoclimate interpretations. Based on the new data, the edges of the plateau glacier were established around 2100 m above sea level, its extension was of 57.4 km2 and the maximum thickness ranges from 80 and 130 m along the summits of the range. During the period of maximum extension of the glacier (MG) the plateau had a morphology close to an icecap, whereas with the onset of glacier retreat the ice mass reduced and the glacier become a truly icefield. Finally, during successive stages of retreat the glaciers were individualized and become valley and cirque glaciers. The on-going research regarding the chronology of the glacier maximum (MG) based on 10Be dates, that consider samples from Duque-Trampal, Endrinal and Cuerpo de Hombre glaciers from Sierra de Béjar, provides preliminary dates of 27.2 ± 2.7 and 26.2 ± 0.8 ka BP for the maximum extent of the plateau glacier in this area.

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