Evidencias de volcanismo freatomagmático en el Mioceno de Chile central
Evidence of phreatomagmatic volcanism in the Miocene of central Chile
Clavero, J., Droguett, B., Ramírez, V.
Abstract
Describes maar-diatreme systems in the Farellones Formation in two sectors of the central Chilean Andes: El Manzano (Cajón del Maipo), with at least 6 structures, and the upper Mapocho basin, with at least 3 aligned N–S.
At El Manzano, conduit-fill and inner-fill facies crop out together with andesitic subvolcanic bodies intruded into the still unconsolidated deposits; the crater and tuff-ring facies have been eroded. In the upper Mapocho, tuff-ring facies are also preserved, with hydrothermal alteration (silicification, quartz-alunite, silica-jarosite).
The authors suggest that this type of volcanism is more frequent than previously recognised in the Oligocene–Miocene units of central Chile.
