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Volcan Llaima (38.7°S; Andean Southern Volcanic Zone) II: An integrated geochemical, petrologic, and volcanological study of an active and dangerous arc volcano in southern Chile

Applicant Schaltegger Urs
Number 125019
Funding scheme Project funding
Research institution Département des sciences de la Terre Université de Genève
Institution of higher education University of Geneva - GE
Main discipline Geochemistry
Start/End 01.06.2009 - 31.12.2012
Approved amount 543'046.00
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Keywords (8)

geochemistry; petrology; physical volcanology; Volcan Llaima; Chilean Andes; Arc volcanism; U-series; subduction

Lay Summary (English)

Lead
Petrologists and geochemists concerned with magmatic processes at volcanoes have generally focused their efforts on understanding the origin of magmas in the Earth’s mantle (partial melting) and the compositional evolution of these magmas (differentiation) during ascent prior to eruption. This “ivory tower” approach misses an opportunity to address the eruptive dynamics of active volcanoes with many of the same data that we regularly apply to basic research problems.
Lay summary
Volcan Llaima (38.7° S), the primary focus of this project, is one of the most active volcanoes in the Andean arc, with an average repose period of 3.5 yrs since the onset of reliable historic records (~1850). The other five volcanoes being investigated in this study (36.7-41° S) have erupted since 1835, and there have been four major eruptions in Chile with variably negative consequences since 2008 (two at Llaima). We are combining an extensive characterization of lavas and pyroclastic deposits at Llaima with numerical fluid dynamics modeling in order to find the links between magmatic processes and the processes that trigger eruptions. Arriving at quantitative answers to such questions for specific volcanoes will take many years, but we have made significant progress in this area, in addition to providing new information about magma genesis and evolution in this part of the Andean arc
Direct link to Lay Summary Last update: 04.02.2013

Responsible applicant and co-applicants

Employees

Collaboration

Group / person Country
Types of collaboration
Langmuir Group - Harvard University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Andres Tassara, University of Concepcion Chile (South America)
- in-depth/constructive exchanges on approaches, methods or results
Fidel Costa, University of Barcelona Spain (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Bourdon Group/ETHZ Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Goldstein Group/Lamont-Doherty Earth Observatory, Columbia University United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
Alain Burgisser, ISTO/CNRS, Orleans France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Olivier Bachmann, University of Washington United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Associated projects

Number Title Start Funding scheme
116313 Volcan Llaima (38.7 OS; Andean Southern Volcanic Zone): An integrated geochemical, petrological, and volcanological study of an active and dangerous arc volcano in southern Chile 01.06.2007 Project funding
116313 Volcan Llaima (38.7 OS; Andean Southern Volcanic Zone): An integrated geochemical, petrological, and volcanological study of an active and dangerous arc volcano in southern Chile 01.06.2007 Project funding
55852 Petrologic, volcanologic, and geochronologic studies of continental calc-alkaline magmatism II 01.06.1999 Project funding

Abstract

Any investigation that leads to a significantly deeper knowledge of arc volcanism is a contribution towards the understanding of a plate tectonic setting of fundamental importance. The Andean arc is a product of one of the world’s classic convergent margins, and we stress throughout this proposal that Llaima has a number of special attributes which make it a particularly advantageous subject for the ambitious and multifaceted project that we propose, and for resolving important problems that we are addressing. Llaima is a useful counterpart to the much more complicated and long-lived magmatic record at Tatara-San Pedro. The relative simplicity of both magma genesis and differentiation at Llaima, in combination with the unprecedented geochemical data set that we propose to collect, will allow us to generate unusually well quantified petrologic models for both the origin and evolution of magmas in the Andean Southern Volcanic Zone, and these will serve as end-member reference modes for magmatic processes and components in this arc. The outcome of numerical modeling of the last four centuries of Strombolian activity at Llaima will be knowledge of the physical processes controlling the explosive potential of this volcano. This has implications at the national level owing to the high potential of any Strombolian eruption at Llaima to trigger far-reaching lahars, and to similarities with activity at near-by Villarrica. Our insights into the relationships among crystal content, magma stagnation, magma recharge, and eruptive mode may be broadly applicable and may shed light on the mechanisms that control the onset and unfolding of a canonical style of eruptive activity. We hope that these results will be incorporated into eruption forecasting methodology.
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