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Glaciations in the Cantabrian Divide: The Quaternary glacial evolution in the Sierra de Cebolleda (León)

Abstract:

The Sierra de Cebolleda (León province, Castilla y León) is a 10 km length part of tha Cantabrian Divide, located to the South of Picos de Europa, the highest massif in the Cantabrian Mountain. The high lithological diversity and monocline structure have addressed the Quaternay glaciation. The paper studies the glacial evolution by mean of the glacial features and the objective is to know the temporal evolution and extent of Quaternary glaciers and to establish as accurate as possible correlations with the other Cantabrian massifs. A geomorphological map to scale 1/25,000, ELA calculation of each glacier and glacial period, and a morphostrtigraphical analysis, including aspect, front altitudes, glaciers lenght and ELA have been made. Eleven glaciers systems have been reconstructed, defining in the North side tongues longer than 5 km and a medium altitude of fronts of 1120 m a.s.l. The moraine complex point to between one and four glacial stages in each valley. Four glacial stages have been establish: two of alike extent (F1 and F2), a retreated and equilibrium stage (F3) and a marginal glacial stage defined by small cirque glacier (F4) and extreme periglacial processes (rock glaciers, block slopes, block streams and stratified debris). Finally, the glacial stages have been correlated with known absolute dating of other massif of the Cantabrian Mountain.