Project

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Integrating U-series and petrology to constrain the time scales of arc magmatism

Applicant Reubi Olivier
Number 126399
Funding scheme Ambizione
Research institution Institut für Geochemie und Petrologie ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Geochemistry
Start/End 01.12.2009 - 30.11.2012
Approved amount 424'803.00
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All Disciplines (2)

Discipline
Geochemistry
Mineralogy

Keywords (6)

Isotope geochemistry; Mineralogy; Arc magmatism; Volcano; Earth sciences; Uranium-series

Lay Summary (English)

Lead
Lay summary
Arc magmatism plays a key role in the evolution of the Earth as producer of continental crust and carrier of chemical elements recycled from subducted oceanic plates. Fluxes of elements through subduction zones, particularly volatile elements, have important implications for the evolution of the continental crust, volcanic eruptions, climatic changes and formation of ore deposits. In view of its scientific, environmental and economic importance, understanding subduction-related volcanism stands as one of the great challenges facing earth scientists. Because of the tectonic complexity of subduction zones, multiple components and processes compete to produce the magmas erupted from, often threatening, arc volcanoes. Decades of geochemical and petrological research have provided good constraints on the processes and components involved, however their relative contribution, interdependence and variability in space and time are open to debate. Establishing the time scales of magmatic processes is an essential step to assess their interdependence and the fluxes of melts and fluids through the crust above subduction zones. Clear understanding of the parameters controlling volcanic output rates, the functioning of subvolcanic magmatic systems, and the mechanisms controlling eruption styles is not achievable without tight constrains on the time scales involved. The short-lived isotopes produced in radioactive decay chains of Uranium and Thorium are excellent time-dependant tracers of recent geological processes. The contrasted chemical behaviour in fluids and melts, as well as the range of half-lives (75'000 years to 138 days) of the daughter nuclides make of the Uranium-series the weapon of choice to constrain the time scales of subduction zone volcanism.

This project aims at addressing several fundament questions in petrology and volcanology by conducting complete U-series systematics for time series of historical eruptions from two hyper-active arc volcanoes, Volcán de Colima, Mexico and Batur volcano, Indonesia. The key innovative aspect of this project is to integrate the full spectrum of U-series nuclides measured on bulk rock samples, crystal separates and in-situ in Uranium-rich minerals with in depth mineralogical studies to a level never attempted before. This project is expected to significantly contribute to a better understanding of the time scales of the processes controlling subduction zone magmatism and of their interdependence. The outcomes are expected to improve our comprehension of the dynamics of subvocanic magmatic systems, of the fluxes of melts and fluids through these systems and of the controls this exercise on eruption style.
Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
Assimilation of the plutonic roots of the Andean arc controls variations in U-series disequilibria at Volcan Llaima, Chile
Reubi O, Bourdon B, Dungan MA, Koornneef JM, Selles D, Langmuir CH, Aciego S (2011), Assimilation of the plutonic roots of the Andean arc controls variations in U-series disequilibria at Volcan Llaima, Chile, in EARTH AND PLANETARY SCIENCE LETTERS, 303(1-2), 37-47.
A new method for U-Th-Pa-Ra separation and accurate measurement of 234U-230Th-231Pa-226Ra disequilibria in volcanic rocks by MC-ICPMS
Koornneef J.M. Stracke A. Aciego S. Reubi O. and Bourdon B. (2010), A new method for U-Th-Pa-Ra separation and accurate measurement of 234U-230Th-231Pa-226Ra disequilibria in volcanic rocks by MC-ICPMS, in Chemical Geology, 277, 30-41.
Petrological monitoring of Volcan de Colima magmatic system: the 1998-2010 activity
Reubi O. Blundy J. Pickles J, Petrological monitoring of Volcan de Colima magmatic system: the 1998-2010 activity, in Varley N. (ed.), Springer, -, -.

Collaboration

Group / person Country
Types of collaboration
University of Wyoming United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Universite de Geneve Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
Ecole Normale Supérieure de Lyon France (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
University of Bristol Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
Paul Sherrer Institute Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Adamello 4d 03.09.2012 Bagalini
Goldschmidt conference 02.07.2012 Montreal
AGU conference 05.12.2011 San Francisco, USA
Goldschmidt conference 15.08.2011 Prague, Czech Republic
State of the Arc 20.09.2010 Santorini


Associated projects

Number Title Start Funding scheme
109813 Control of magmatic and degassing dynamics on the volcanic activity at Volcán de Colima, Mexico 01.12.2005 Fellowships for prospective researchers

Abstract

Arc magmatism plays a key role in the evolution of the Earth as producer of continental crust and carrier of chemical elements recycled from subducted lithosphere. Fluxes of elements through subduction zones, particularly volatile elements, have important implications for the evolution of the continental crust, volcanic eruptions, climatic changes and formation of ore deposits. In view of its scientific, environmental and economic importance, understanding subduction-related magmatism stands as one of the great challenges facing earth scientists. Because of the tectonic complexity of subduction zones, multiple components and processes compete to produce the magmas erupted from, often threatening, arc volcanoes. Decades of geochemical and petrological research have provided good constraints on the processes and components involved, however their relative contribution, interdependence and variability in space and time are open to debate. Establishing the time scales of magmatic processes is an essential step to assess their interdependence and the fluxes of melts and fluids through the crust above subduction zones. Clear understanding of the parameters controlling volcanic output rates, the functioning of subvolcanic magmatic systems, and the mechanisms controlling eruption styles is not achievable without tight constrains on the time scales involved. The short-lived isotopes produced in radioactive decay chains of U and Th are excellent time-dependant tracers of recent geological processes. The contrasted chemical behaviour in fluids and melts, as well as the range of half-lives (75 kyr to 138 d) of the daughter nuclides make of the U-series the weapon of choice to constrain the time scales of subduction zone volcanism. U-series disequilibria have provided fundamental constrains on; (i) the timing of slab fluid input in the mantle wedge, (ii) the dynamics of mantle melting, (iii) the ascent rates of magmas, (iv) the time scales of differentiation, (v) the residence times of crystals, and (vi) the time scales of magma degassing. Like all significant scientific advances, the unprecedented constrains provided by the U-series have also opened numerous questions. This project aims at addressing several of these newly arisen questions regarding arc magmatism by conducting complete U-series systematics for time series of historical eruptions from two hyper-active arc volcanoes, Volcán de Colima (VDC), Mexico and Batur volcano, Indonesia. Important problems in igneous petrology, geochemistry and volcanology that will be addresses include: (1) Are U-series disequilibria in silicic melts inherited features derived from slab fluid flux and mantle partial melting or record silicic melt production within the crust. (2) To which extent do partial melting and assimilation of plutonic rocks and cumulates contribute to Ra excesses. (3) Are there significant variations in differentiation time scales for mafic and silicic melts from a single volcano. (4) What are the time scales of crystallisation in the subvolcanic magmatic system beneath hyper-active volcanoes, do they vary for successive eruptions and what are the implications for the dynamics and structure of these systems. (5) Can the different crystallization ages suggested by semi-independent U-series chronometers be integrated with detailed mineralogical data into a coherent model. (6) Do gas fluxes indicated by 210Pb disequilibria relate to degassing trends recorded by H2O and CO2 measurements in melt inclusions and is there a correlation with the SO2 emission rate measured by UV spectrometers at the surface prior to the eruptions. (7) To which extent are the time scales of degassing and crystallization similar and what are the implications in terms of magma rheology, eruption dynamics modelling and volcano monitoring. (8) What are the time scales of production and crystallization of medium size silicic magmatic systems producing catastrophic caldera-forming and what are the implications for volcanic hazard. The key innovative aspect of this project is to integrate the full spectrum of U-series nuclides measured on bulk samples, crystal separates and in-situ in U-rich accessory phases with in depth mineralogical studies to a level never attempted before. The frequent eruptive activity (ongoing eruption at Colima), the variations in eruption style and the range of erupted magma composition make of the two volcanoes we propose to investigate a rare opportunity to address several fundament questions in petrology and volcanology. This project is expected to significantly contribute to a better understanding of the time scales of the processes controlling subduction zone magmatism and of their interdependence. The outcomes should improve our comprehension of the dynamics of subvocanic magmatic systems, of the fluxes of melts and fluids through these systems and of the controls this exercise on eruption style.
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