If we move from the foothills to the high basin of the Mendoza River, Espizua (1989) describes the Penitentes, Horcones and Almacenes drifts. Subsequently, the Horcones deposits were assigned by Pereyra and González Díaz (1993) to flows originating from rotational landslides. Recently Fauqué et al. (2008a and b) considered the three drift deposits as distal flows of rock avalanches. In this case there is no doubt that the area was glaciated during the Pleistocene, but what is being discussed here is the Aconcagua Mountain Guides validity of the glacial stratigraphy of the Mendoza river basin, based on the mass shear deposits identified .
These antecedents allow us to observe that glacial deposits and mass removal deposits have been confused for more than 60 years. Therefore, the need arises to review and reinterpret the morphology together with the sedimentological characteristics of the high mountain Quaternary deposits. The incorrect identification as moraines made of deposits corresponding to rock avalanches that have survived erosion in previously glazed terrain, has been pointed out by Hewitt (2002) as frequent in many parts of the world. Detailed mapping of Quaternary deposits has been insufficient in many high mountain regions, despite the fact that it is linked to knowledge of geological risks.
It was precisely a study linked to the Aconcagua Ascents geological risks that affect the town of Puente del Inca, the reason for which the issue of the genesis of the deposit located in the Horcones ravine was addressed, in order to discern if it is of glacial origin or associated with mass removal. The resolution of this problem made it necessary to extend the observations to the Cuevas river valley and to the deposit assigned to the Penitentes drift.
The recent reinterpretations of the Horcones, Almacenes and Penitentes drifts were presented in abstracts at the XVII Argentine Geological Congress, therefore we intend here to provide all the information on which the new interpretation of the three deposits is based. We will start with the Horcones deposit and finally we will refer to the one located immediately downstream from the town of Penitentes. In the investigation of the Aconcagua Treks Horcones, Almacenes and Penitentes drifts, special attention was paid to the surface morphology of the deposits, their location and extension in the valleys and their volume. The morphological characteristics of the valleys of Horcones Inferior, Horcones, Tolosa, Cuevas and Mario Ardito were also analyzed, comparing them with other valleys in the area. The southern wall of Cerro Aconcagua was also studied in detail, as some anomalous and/or unusual morphologies were noted in it.