Quaternary Glaciations in the Rio Mendoza Valley, Argentine Andes

摘要: In the Rio Mendoza valley, five Pleistocene drifts and one Holocene drift are distinguished by multiple relative-age criteria, including surface-rock weathering, development of rock varnish, moraine morphology, soil-profile development, stratigraphic relationships. Several absolute ages suggest a preliminary chronology. During oldest (Uspallata) glaciation, system valley glaciers flowed 110 km from Andean drainage divide 80 Cerro Aconcagua to terminate at 1850 m. Drift this ice advance is older than widespread tephra dated fission-track 360,000 ± 36,000 yr. Punta de Vacas advance, terminated 2350 m, while during subsequent Penitentes glacier ended 2500 A travertine layer overlying has U-series age 24,200 2000 yr B.P. The distribution Horcones Drift, which inferred represent last glacial maximum, delimits an independent stream that 22 down 2750 later readvance (Almacenes) reached 3250 Confluencia considered be Neoglacial in extends downvalley 3300 sequence compared with those studied Caviedes (1972) along on Chilean flank Andes.