La última deglaciación en los Pirineos a partir de datación de superficies de exposición mediante 10Be

Abstract

We use the Terrestrial Cosmonuclide 10Be to deduce the exposure age of glacial surfaces in three glacial basins: the Noguera Ribagorzana valley (South-Central Pyrenees), the Querol valley (South-Eastern Pyrenees) and the Pau valley (North-Western Pyrenees). 10Be concentration data allow us to infer the minimum abandon age of the surfaces sampled (age of deglaciation). The dataset obtained from the Last Pleniglacial deposits shows that the main moraine abandon phase could be synchronous, or slightly previous, to the global Last Glacial Maximum (LGM). Although the Pyrenean Last Pleniglacial could have started tens of thousands of years before the LGM, the data we present here do not support the idea proposed in earlier works of an advanced stage of deglaciation in the Pyrenees around the LGM. The rest of glacial deposits dated in this work seem to be formed around the Greenland Stadial 1. At least three phases of moraine abandonment during Deglaciation can be detected c. 14.2, 12.5 and 11.0 10Be ka.