Stratified scree in the Central Spanish Pyrenees: palaeoenvironmental implications

Sedimentological, geomorphological and palynological study of three stratified screes from two environments in the central Spanish Pyrenees allows reconstruction of climate and vegetational change since the last glacial maximum. In both localities (at 700 and 1000 m a.s.l.) the deposits show a similar stratigraphy: (i) a basal stratified scree, in one case fossilized by speleothems; (ii) a palaeosol, with abundant charcoal and evidence of human activity; and (iii) a massive coarse scree. The stratified scree developed during the glacial maximum and late glacial. A humid period during the early Holocene was characterized by speleothem formation and carbonate cementation in some screes. Forest fires around 3300 BP were widespread in the Pyrenees and were probably related to human impact. Recent scree reactivation due to an increase in clast supply is limited to cold stages during the late Holocene.