Details of Award
NERC Reference : NE/E014127/1
STOKING THE FIRES: DYNAMICS OF SILICIC MELT ACCUMULATION BENEATH SUPERVOLCANOES
Fellowship Award
- Fellow:
- Dr B Charlier, The Open University, Environment, Earth & Ecosystems
- Grant held at:
- The Open University, Environment, Earth & Ecosystems
- Science Area:
- Earth
- Overall Classification:
- Earth
- ENRIs:
- Environmental Risks and Hazards
- Science Topics:
- Volcanic Processes
- Abstract:
- Large eruptions ('supereruptions', >300 km3) of silica-rich magma worldwide are notable because of their devastating impacts, far beyond those seen in human history. In addition to the widespread effects caused by the eruption products spread over the landscape, such eruptions have been associated with impacts on global climate comparable to those of a nuclear war. However, the same volcanoes that generate such vast eruptions also produce small eruptions that would have had only local impacts. Why? How might one tell the difference in advance and thus be able to undertake appropriate hazards assessment, monitoring and forecasting? Also, should unrest occur at a large silicic volcano how might one tell what is happening? Finding answers to these questions poses great challenges. This proposal will utilise innovative micro-analytical techniques and interpretations on single crystals to measure where in the Earth's crust, by what mechanisms, and at what rates magma has been created below silicic volcanoes with a proven record of large eruptions. Minerals in eruption products contain within them a record, analogous to the growth record in tree rings, of the changing physical/chemical conditions under which they grew in the magma. Many studies have established these changing conditions, but only now it is possible to address at the same time WHEN the mineral growth occurred. This is possible because of zircons, a trace but ubiquitous mineral in silica-rich volcanic rocks. Individual zircon crystals can be (a) dated to establish how old particular parts of a crystal are, (b) analysed for titanium, a trace contaminant, the amount of which indicates how hot the magma was when the zircon crystallised, and (c) have any associated melt inclusions, commonly present and representing magma trapped within the growing crystal, analysed. For part (c), analyses can be done for (i) volatiles (water, carbon dioxide) that power the eventual eruption and control its explosiveness, and the contents of which indicate the depths in the crust at which the inclusions were trapped, (ii) volatiles that contribute to global environmental impacts (e.g., sulphur, chlorine, fluorine), (iii) trace elements that identify the different magmas that contributed to the final product and (iv) isotopes, particularly of strontium, that fingerprint the sources of those magmatic ingredients. Similar data can be collected in other crystals but only the zircons can be dated so as to provide the chronologies. This project will analyse zircons and other associated crystal species from contrasting eruptions at three volcanoes or areas that have had young, large silicic eruptions. These are: Toba (Indonesia) where one of the world's largest eruptions occurred just 74,000 years ago; central Taupo Volcanic Zone (TVZ; New Zealand), the world's most frequently active and productive silicic system which generated the second largest eruption worldwide in the past 100,000 years only 26,500 years ago; and Yellowstone (USA) which last erupted huge lava flows around 70,000 years ago. All three areas are likely to erupt in the future. The three areas are chosen because their youth allows use of the U-Th disequilibrium techniques to date zircons from modern times back to about 250,000 years, and all three have established geological backgrounds that allows the new results to be set in context. At Toba and Yellowstone, products of single large eruptions (representing integrated growth of magma bodies) will be used to model their assembly in the crust. In the TVZ an exceptionally detailed eruptive record allows 'snapshots' of the assembly process for magma bodies from <0.01 to >500 km3 to be captured. Results from this work will contribute new data and ideas to how large silicic volcanoes work, and generate models for the rapidity, depths and physical/chemical properties of growing magma bodies that can be used to inform targeted monitoring of silicic volcanoes worldwide.
- NERC Reference:
- NE/E014127/1
- Grant Stage:
- Completed
- Scheme:
- Postdoctoral Fellow (FEC)
- Grant Status:
- Closed
- Programme:
- Postdoctoral Fellowship
This fellowship award has a total value of £246,207
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Estate Costs | DI - Staff | DA - Other Directly Allocated | DI - T&S |
|---|---|---|---|---|---|
| £13,403 | £89,353 | £28,543 | £97,009 | £11,169 | £6,730 |
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