Cartografía geomorfológica de cuevas y dataciones por el método U-Th. Contribución a la espeleogénesis en los Picos de Europa (Norte de España)

Abstract

A speleogenetical model of two shafts (Torca Teyera and Torca La Texa) from Picos de Europa is proposed. The spatial distribution of the processes is established by geomorphological mapping of the cavities at a 1:500 scale, according genetical criteria for the classification of cave features. The temporal evolution of the cave is established from relative chronology and absolute dating of eight selected samples with 234U/230Th dating technique. The chronology shows that the origin of Torca Teyera and La Texa began at least during the Mid Pleistocene controlled by the dropping of the base level. Fluviokarstic activity and speleothems growth started prior 300 ka; both processes continued at least until 185 ka, at Torca Teyera, and 156 ka at Torca La Texa. The main flowstone of Torca La Texa precipitated before 65 ka. These results are consistent with the previously established speleogenetical model according to which new shafts and canyons began to develop downwards during Alpine uplift cutting the old cave levels that remained perched.