Large ignimbrite eruptions and volcano-tectonic depressions in the Central Andes: A thermomechanical perspective

Shanaka De Silva, George Zandt, Robert Trumbull, José G. Viramonte, Guido Salas, Néstor Jiménez

Research output: Chapter in Book/Report/Conference proceedingChapterpeer-review

145 Scopus citations


The Neogene ignimbrite flare-up of the Altiplano Puna Volcanic Complex (APVC) of the Central Andes produced one of the best-preserved large silicic volcanic fields on Earth. At least 15 000 km3 of magma erupted as regional-scale ignimbrites between 10 and 1 Ma, from large complex calderas that are typical volcano-tectonic depressions (VTD). Simple Valles-type calderas are absent. Integration of field, geochronological, petrological, geochemical and geophysical data from the APVC within the geodynamic context of the Central Andes suggests a scenario where elevated mantle power input, subsequent crustal melting and assimilation, and development of a crustal-scale intrusive complex lead to the development of APVC. These processes lead to thermal softening of the sub-APVC crust and eventual mechanical failure of the roofs above batholith-scale magma chambers to trigger the massive eruptions. The APVC ignimbrite flare-up and the resulting VTDs are thus the result of the time-integrated impact of intrusion on the mechanical strength of the crust, and should be considered tectonomagmatic phenomena, rather than purely volcanic features. This model requires a change in paradigm about how the largest explosive eruptions may operate.

Original languageEnglish
Title of host publicationMechanisms of Activity and Unrest at Large Calderas
EditorsC. Troise, G. De Natale, C.R.J. Kilburn
Number of pages17
StatePublished - 2006

Publication series

NameGeological Society Special Publication
ISSN (Print)0305-8719


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