Glaciation and Periglacial Morphology in the Northwestern Venezuelan Andes

Abstract. Evidences of previous glaciation in the northwestern Venezuelan Andes, mainly in Páramo de Piedras Biancas, include a main morainic level at 3400 to 3700 m, and minor moraines at higher elevations up to about 4300. Glaciated valleys, hanging valleys, rock, steps, glacial channels, cirques, arêtes, horns, striae and grooves on polished rock, roche mountonnés, and whaleback forms, are the main evidence of glacial sculpture and erosion. The main morainic level probably represents a Late Wisconsin glacial advance, and the higher moraines are either neo-glacial or due to minor readvances during the main postglacial retreat. The main morainic level, 400 m higher than that in the southeastern Venezuelan Andes, indicates that the glacial climate was drier in the northwestern part than in the southeastern part of this mountain range. Present-day periglacial features include micro-terrassettes, turf exfoliation, talus, and striated ground, above 3500 m; and nonsorted stripes, sorted polygons or sorted circles, and sorted nets, above 4000 m. The present-day periglacial zone is located between approximately 3600 and 4700 m. During glacial times it probably readied down to 2400 m in the southeastern, and 2900 m in the northwestern parts of the Venezuelan Andes.