The AAR method (Accumulation Area Ratio) for palaeo-ELAs reconstruction: metholodolical analysis and application in the Valdecebollas Massif (Cantabrian Mountains)

Abstract

There are different methods for palaeo-ELAs reconstruction. The AAR method (Accumulation Area Ratio) gives the most reliable results and is one of the most frequently used methods at the moment. To calculate the "palaeoELAs" of the Quaternary glaciation of the Valdecebollas Massif the use of GIS programs is applied. It is shown the use of the method as well as some considerations about its application and the factors that play an important role in the reconstruction. The calculation of the ELA in the Valdecebollas Massif allows to provide complementary information to the morphological and morphometrical analysis. The environmental conditions of the massif in two glacial stages are established: a glacial maximum with homogeneous behaviour of their both slopes (F. 1) and a stage of retreat (F. 2) with a different glacial behaviour between north and south faces. In this phase, on north face the retreat is interrupted with balances of the millennium smallest order.