Reinterpretation of the deposits assigned to Pleistocene glaciation in the Mendoza river basin

Abstract

Based on the the Puente del Inca (Mendoza) land management program, a susceptibility landslide map was realized. The map included the Horcones Drift deposit interpreted later as a complex type landslide. This led us to make a review of the Horcones Drift deposit reaching, as the study progressed, the conclusion that all the glacial basin stratigraphy needed to be revised. Consequently, studies and investigations were carried out led us to present a new proposal in which from the six terminals moraine described for the Mendoza river basin, only one was of glacial origin. The Uspallata Drift is here reinterpreted as an old nonfunctional piedmont deposit. In regard to Punta de Vacas Drift it is difficult to sustain its existence because of the scarce outcrops, the absence of a terminal moraine and the new absolute ages obtained and presented in this paper. The Penitentes Drift seems to be the result of a post-glacial debris flow, which started at the head of Mario Ardito creek. Regarding the Almacenes and Horcones Drifts, they are distal cogenetic flows originated from the Aconcagua south hill slope mega-landslides. The Confluence Drift is the only true glacial deposit, as it was originally defined composed of several marginal moraine arcs. Because of this new interpretation of the deposits we consider that it is necessary to review the glacial stratigraphy of the Mendoza river basin.