Details of Award
NERC Reference : NE/C003276/1
Extent and Environmental Impact of Permo-Triassic Siberian Trap Volcanism
Grant Award
- Principal Investigator:
- Professor AD Saunders, University of Leicester, Geology
- Grant held at:
- University of Leicester, Geology
- Science Area:
- Marine
- Earth
- Atmospheric
- Overall Classification:
- Earth
- ENRIs:
- Global Change
- Science Topics:
- Volcanic Processes
- Sediment/Sedimentary Processes
- Palaeoenvironments
- Climate & Climate Change
- Abstract:
- 250 million years ago, at the end of the Permian, a substantial proportion of life on Earth was destroyed as a result of catastrophically changing global environments. The oceans and atmosphere became warmer, and the oceans anoxic, stifling whole habitats. Just like the end-Cretaceous mass extinction, there are two main primary culprits: meteorite impact, and massive flood basalt volcanism. Unlike the end-Cretaceous event, no-one has found any convincing evidence for a large meteorite impact at the Permo-Triassic boundary (although the search continues), but there is strong evidence that the Siberian Trap volcanism is contemporaneous with the extinction. This association between volcanism and mass extinction is recorded at several other times over the last 300 m.y., and cannot be pure coincidence; there appears to be an causal link between large-scale basaltic volcanism and mass extinctions. The challenge is to demonstrate, convincingly, that volcanism can indeed cause such global devastation. Release of large masses of carbon dioxide, triggering atmospheric warming, leading to oceanic warming and anoxia and release of methane hydrates - and thus developing a powerful positive feedback - is satisfyingly apocalyptic but to date no-one has shown how this can be done. Indeed the fluxes of CO2 are insignificant when considered on the timescale of emplacement of flood basalt provinces (around 1 m.y.), and much less than, say, the current anthropogenic carbon release rates. Studies of the environmental impact of the Siberian Traps have been hampered by lack of knowledge of their extent and duration, both parameters being essential to calculate gas fluxes. We have already proven that a large portion of the Traps extend beneath the West Siberian Basin, but we are unsure how far. This project is designed to find out, by studying samples from fringes of the province - in the Urals, in southern Siberia, and from areas of the Siberian Craton that have not hitherto been properly dated. It is generally accepted that the Traps were erupted in a short duration, but this is based mainly on a few samples from a relatively small proportion of the Trap outcrop. Again, we shall test this idea by dating samples from key localities in the Traps. We shall endeavour to determine the dissolved gas content of the Trap magmas by analysing small melt inclusions in crystals in the Trap lavas. This will provide, for the first time, reliable estimates of the gas fluxes from the lava flows, as has been estimated for more recent flood basalt provinces. The more remote (and global) effects of the Trap volcanism will be assessed by measuring the osmium isotope signature of sediments from the Permo-Triassic reference section in Meishan, China. Osmium is a rare trace element with a short residence time (<40,000 y) in ocean water. Osmium from the Trap basalts is transported to the oceans where it mixes and is transported around the globe. The basaltic osmium will impart a particular isotopic signature (a bit like a chemical fingerprint) and should be detected in the sediments in China, which were deposited several thousand kilometres away from the original volcanism. We can then use this information to determine the timing of volcanism in relation to the actual Permo-Triassic extinction event, and distinguish between a transient meteorite impact and volcanism at the Permo-Triassic boundary. This proposal has resonance with the current debate on climate change. Understanding whether and how a major flood basalt event can perturb the Earth's climate clearly has implications for our understanding of the present system. For example, if it is possible to show that a succession of flood basalt eruptions is able to force the climate to the extent of triggering a major ecological crisis, then the implications for the modern world, where the CO2 flux rates are far larger, are serious.
- NERC Reference:
- NE/C003276/1
- Grant Stage:
- Completed
- Scheme:
- Standard Grants Pre FEC
- Grant Status:
- Closed
- Programme:
- Standard Grant
This grant award has a total value of £201,172
FDAB - Financial Details (Award breakdown by headings)
| Total - Staff | Total - T&S | Total - Other Costs | Total - Indirect Costs |
|---|---|---|---|
| £100,357 | £15,762 | £38,889 | £46,163 |
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