The evolution of the Upper Pleistocene glaciers in the Central Spanish Pyrenees. A case study in the Escarra and Lana Mayor glaciers, High Gállego Valley

Abstract

The evolution of the Escarra and Lana Mayor glaciers (Upper Gállego valley, Central Spanish Pyrenees) is studied, and the main stages from the Glacial Maximum until the end of the Late Glacial are assessed. This paper confirms that the maximum extent of the Pyrenean glaciers during the Upper Pleistocene was reached very early (before 30,000 years B.P.). During the coldest period (around 20,000 years B.P.) a new advance occurred, though of lower intensity than the previous one, due probably to the negative effect of the oceanic ice on the humidity content of the air masses. Later, other minor advance has been identified, followed by a stage of debris-covered glaciers and a stage of moraines located close to the cirque backwalls. Sediments accumulated on lakes have allowed to identify and date a fluvial capture and a large mass movement during the LGM.