State of arts of Mendoza River geomorphology

MOREIRAS S.M.

Encuentro; ICES 7. Séptimo Encuentro del “Internacional Center For Earth Sciences”.; 2011

The vision of global main glaciations during the 70´s decade delayed recognition of landslides. These processes began to be identified at this sector of Central Andes (32 S) lately. The earliest description of palaeolandslides along the valley of Las Cuevas and Mendoza rivers, Argentina, comes from a geomorphological study in the 70´s by Salomon (1969). As glacial deposits and landslides have both chaotic characteristics and bad selection distinguishing of both deposits was a hard matter. Initially, Abele (1984) reinterpreted ancient moraines of the Aconcagua and Yeso valleys (Caviedes 1972) as landslides in the Chilean Andes. Following these ideas, several studies reinterpreting glacial origin of Quaternary deposits were performed. But on the other hand, Wayne and Corte, 1983 reinterpreted the genesis of chaotic deposits described as debris flows developed in alluvial fans of the Cordillera Frontal piedmont (Polanski, 1958) promoting the existence of four glaciations along Rio Blanco River. Actually, current researches in Argentinean Andes reinterpret several moraine deposits as collapses. The Holocene deposit described as Horcones moraine (Espizúa 1993) is presently considered as the distal facies of a rock avalanche sourced in the South face of Mount Aconcagua (6959 m asl). This debris material travelled 30 km arriving to the Cuevas River where generated a palaeolake (Fauqué et al. 2008c; Fauqué et al. 2009). Likewise, the existence of Penitentes glaciation is discussed. The outwash of this drift has been recently re-interpreted as the debris flow resulting from the Mario Ardito rock avalanche (Fauqué et al. 2008b). Similarly, deposits originally attributed to a glacial origin in the upper basin of the Las Cuevas River (Suárez 1984) are now described as five landslides (Goyete, Negro, Lagunita, Susanita and Matienzo) (Moreiras 2007; Moreiras et al. 2008, Lauro 2010).