The glaciation of Serra de Queixa-Invernadoiro and Serra do Gerês-Xurés, NW Iberia. A critical review and a cosmogenic nuclide (10Be and 21 Ne) chronology.

Abstract

[Abstract]The Serras of Queixa-Invernadoiro and Gerês-Xurés in the NW of the Iberian Peninsula are two small mountain massifs located at low altitude that were glaciated in the Pleistocene. The prevailing granitic lithology was a problem for mapping glacial forms (in many cases interpreted as banal granite forms) and for the identification of the tills (misunderstood as remains of regolith). A combination of geomorphological techniques (genetic mapping of granite forms and deposits), the micromorphological study of till thin sections and the morphoscopy of quartz grains at the SEM enabled to establish a model of the geomorphological evolution complemented with the chronology by cosmogenic nuclides (21Ne and 10Be) of both glacial systems. The obtained results represent the glacial evolution of the area from circa 250 ka B.P.