Late Pleistocene and Holocene tephrochronology of Mendoza Province, Argentina.

BOSCH A.; STERN CH.; MOREIRAS S.M.

Congreso; Congreso Geológico Chileno, La Serena,; 2015

Rhyolitic pyroclastic flows and tephra from the Pleistocene (450 ka) eruption of the Laguna Diamante caldera comprise the largest volume of pyroclastic material in northwest Mendoza Province, but trace-element data indicate that 1-3 meter thick rhyolite tephra deposits which outcrop on both the southwest (Cacheuta) and northeast (Borbollon) margins of the city of Mendoza have an independent origin. These data, and preliminary chronology, imply at least two different large late Pleistocene eruptions, both younger than that of the Diamante caldera, possibly of Tupungato volcano or the Tupungatito caldera. Tephra from these eruptions also outcrop sporadically in late Pleistocene sediments along the international highway (Route 7) from the border with Chile to Mendoza. Numerous Holocene andesitic to rhyolitic tephra deposits outcropping along the Andean precordillera are evidence for explosive Holocene activity of a number of Andean volcanoes located near the northern end of the Southern Volcanic Zone (SVZ), in the northern (NSVZ; 33-34°S) and transitional (TSVZ; 34-37°S) SVZ, including possibly Tupungato, Tupungatito, Marmolejo, San Jose, Maipo, Overo, Palomo, Calder del Atuel, Sosneado, Rísco Plateado, Tinguiririca, Planchón-Peteroa, Calabozos, Decabazado Grande, Cerro Azul, San Pedro-Pellado, Laguna del Maule, Nevado de Logaví, Domuyo, Nevados de Chillán and Troman.