Holocene flank-eruptions at the Lanín Volcano (Southern Volcanic Zone), Patagonia

BALBIS CATALINA; IVAN A. PETRINOVIC; JOSÉ AFFONSO BROD

Hamburg

Congreso; 25th Latin-American Colloquium of Geosciences; 2019

Universidad de Hamburgo

The Lanín (39° 38.34'S/71° 30.16'W) is considered an active volcano and is located in the Central South Volcanic Zone (CSVZ) being part of the Villarrica-Quetrupillán-Lanín volcanic chain (VQLVC). The latter comprises three Pleistocene-Holocene composite volcanoes, aligned in a NW-SE direction, and more than 20 monogenetic volcanoes of similar age.Five eruptive units with postglacial age (less than ca. 14000 years) are recognized on the Lanín volcano flanks. Through a facies analysis, the conduits and nature of these eruptions are determined. In this way, vulcanian/subPlinian eruptions are interpreted with the development of considerable eruptive columns, followed by strombolian eruptions in the most significant cases. Vulcanian eruptions produced pyroclastic currents and fall deposits with different transport conditions that affected the N and SE flanks of the volcano, at ca. 10000 years.Through chemical analysis of different eruptive cycle"s rocks, the consanguinity of the involved magma in the eruptive cycle is determined, derived from a singular magmatic system in evolution. The comparison of chemical analyses with those available from the Quetrupillán and Villarrica volcanoes, similar evolutionary histories are interpreted in the magmatic reservoirs of each volcano. That is, basaltic magma recharges in magmatic chambers dominated by fractional crystallization