Lyell Collection
Geological Society, London, Special Publications
Lyell Centre  |   Lyell Collection  |   Subscriptions   |   Geological Society  |   Email alerts  |   Online bookshop  |   Help

Keywords:
Author:
Advanced search>>
This Article
Right arrow Full Text (PDF)
Right arrow References
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Right arrow Citation Map
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow Request Permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by De Silva, S.
Right arrow Articles by Jiménez, N.
Right arrow Search for Related Content
GeoRef
Right arrow GeoRef Citation
Geological Society, London, Special Publications; 2006; v. 269; p. 47-63;
DOI: 10.1144/GSL.SP.2006.269.01.04
© 2006 Geological Society of London

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

Shanaka De Silva1, George Zandt2, Robert Trumbull3, José G. Viramonte4, Guido Salas5 & Néstor Jiménez6

1 Department of Geosciences, Oregon State University, Corvallis, OR 97331 desilva{at}geo.oregonstate.edu
2 Department of Geosciences, University of Arizona, Tucson, AZ, 85721-0077, USA
3 GeoForschungZentrum Potsdam, Telegrafenberg, PB 4.2, 14473, Potsdam, Germany
4 Instituto GEONORTE and CONICET, Universidad Nacional de Salta, Buenos Aires 177, Salta, 4400, Argentina
5 Facultad de Geología, Geofísica y Minas, Universidad de San Agustín, Arequipa, Peru
6 Facultad de Ciencias Geológicas, Universidad Mayor de San Andrés, La Paz, Bolivia

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.





This article has been cited by other articles:


Home page
 ajsHome page
R. S. J. Sparks, C. B. Folkes, M. C.S. Humphreys, D. N. Barfod, J. Clavero, M. C. Sunagua, S. R. McNutt, and M. E. Pritchard
Uturuncu volcano, Bolivia: Volcanic unrest due to mid-crustal magma intrusion
Am J Sci, 2008; 308: 727 - 769.
[Abstract] [Full Text] [PDF]