Details of Award
NERC Reference : NE/M007782/1
Volcanic arc initiation and evolution
Grant Award
- Principal Investigator:
- Dr I Savov, University of Leeds, School of Earth and Environment
- Grant held at:
- University of Leeds, School of Earth and Environment
- Science Area:
- Earth
- Overall Classification:
- Earth
- ENRIs:
- Environmental Risks and Hazards
- Natural Resource Management
- Science Topics:
- Mantle & Core Processes
- Tectonic Processes
- Volcanic Processes
- Abstract:
- The process of Plate Tectonics began nearly 3 billion years ago and since had a profound effect on the environment of our planet. One of the fundamental questions in Earth Sciences is associated with the knowledge of how this process began and what are the conditions tolerating its operation that is blamed for the creation of the continents. The Izu-Bonin-Marianas (IBM) arc-basin intraocenic system in the Western Pacific provides a unique opportunity to address some of these vital questions as it is away from any continental landmass and its tectonic and volcanic history from inception of subduction-related volcanism (~52 M.yrs. ago) to its current state are accessible via modern deepsea drilling. Accordingly, the IBM has been extensively studied in the last 3 decades via DSDP, ODP and now IODP drilling and dredging. As a result the tectonic and volcanic processes operating in the IBM arc in the last 23 M.yrs. (Neogene) are relatively well understood. Problematic is the fact that the early (Paleogene) arc record immediately following the birth of the IBM arc-basin system is currently not available and thus the first part of the story of arc inception and the subsequent creation of arc crust remains incomplete. It is anticipated that during IODP expedition 351 (Site IBM-1) the entire Cenozoic volcanogenic sedimentary record will be recovered. This 1.3 km thick sequence will include the first 25 M.yrs. of volcanic arc activity immediately after the subduction zone began to operate in the Eocene. Using nanofossil evidence (and Ar-Ar dating- not this proposal) will allow the reconstruction of the progressive compositional variations associated with the profound changes following the transition from pure mid-ocean-ridge type environment to gradually maturing arc crust created at volcanic fronts (IBM). One particularly powerful tool to explore this transition is by the use of (now classical) geochemical tracers sensitive to all major constituents involved in the magma generation at arcs- mantle, altered oceanic crust, sediments, seawater and slab fluid. I have chosen a combination of Sr-Nd-Pb and B isotopes to study carefully selected (fresh and with known ages) and well characterised (shipboard ICP data and Leeds electron microscopy-this study) Paleogene volcanic ash and volcaniclasts from Site IBM-1. Boron is not abundant in the mantle and its isotopes fractionate tremendously and in unique fashion during seawater alteration and/or dehydration of the subducted sediments, oceanic crust or serpentinites. The isotopes of Pb have been shown to be an excellent tracer for the nature and provenance of the mantle in the Western Pacific (Indian Ocean versus Pacific Ocean domains) and Sr, Nd and B are all sensitive to the variety of types of subducted sediments and fluids/melts originating from them that may be involved in all stages of the subduction process. My goal will be to complete the gap in the existing isotope records across the IBM. This will uniquely allow the quantitative assessment of the volumes and roles that particular end-members in the "Subduction Factory" play in the development of the IBM arc crust. Indirectly these results will be applicable to any other subduction zone setting. They will provide the geodynamic modelling community with insights for the currently unknown rates and volumes of ingredients involved in the crust generation.
- NERC Reference:
- NE/M007782/1
- Grant Stage:
- Completed
- Scheme:
- Directed (RP) - NR1
- Grant Status:
- Closed
- Programme:
- UK IODP Phase2
This grant award has a total value of £26,252
FDAB - Financial Details (Award breakdown by headings)
| DI - Other Costs | Indirect - Indirect Costs | DA - Investigators | DA - Estate Costs | DA - Other Directly Allocated |
|---|---|---|---|---|
| £6,794 | £4,652 | £11,079 | £1,921 | £1,807 |
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