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E415: Atmospheric fingerprints of Volcanism (Lead Supervisor: Oliver Shorttle, Earth Sciences and Institute of Astronomy)

Supervisors: Oliver Shorttle (Earth Sciences and Institute of Astronomy), Alex Archibald (Chemistry) and Nikku Madhusudhan (Institute of Astronomy)

Importance of the area of research:

Magma production and volcanism are characteristic of geologically active planets and are essential in abiotic chemical cycling.  Early in Earth’s history the combined heat of short-lived radionuclide decay and accretion formed magma oceans.  Subsequent cooling and differentiation produces rocky bodies like modern Earth where volcanism is localised and associated with plate tectonics or mantle plumes.  Throughout these transitions the impact of volcanism on the planet’s atmosphere evolves, from initially being a major source of atmophile elements, to subsequently being a stable part of geochemical cycles and integral to the carbon dioxide-based climate thermostat.  However, major questions remain about the short and long-term impacts of volcanic activity on the atmosphere and how such volcanic forcings of climate may be detected remotely in a planet’s atmosphere more generally, both on Earth and even beyond the solar system.  In addressing these questions this project will make important contributions towards understanding how Earth’s interior, through volcanism, influences habitability and hence extends to addressing the likelihood of us detecting volcanism on other worlds.

Project summary:

This project will link models of volcanic degassing with state-of-the-art atmospheric chemistry codes to understand the impacts of volcanism on climate and the remotely detectable aspects of these phenomena. For this we need new models of volcanism, using gas-phase equilibrium chemistry and injecting it this into realistic atmospheres, where we can then ask are these signals detectable?  These models will provide new insight into conditions on the early Earth, constraining volcanism’s influence on Earth’s early atmospheric evolution. A recent proliferation in the discovery of planets outside our solar system, exoplanets, means we are on the cusp of gaining truly geological insight into how these bodies work.  The subsequent extension in this project could be to identify aspects of their geological activity that may manifest in the detectable part of the planet; their atmosphere.

What the student will do:

This project will comprise three main parts: 1) Developing and running thermodynamic models of magma degassing.  These models will solve for the melt-gas and gas-gas equilibrium volatile speciation for magmas of varying composition.  These calculations are fundamental to predicting the impact of volcanism on climate and have the potential for wide application in deep time and understanding the planet’s dynamics.  2) Taking the results from the magma volatile thermodynamic calculations and feeding these through an atmospheric chemistry code.  To understand what short- and long-term perturbations volcanism can have on atmospheres, and the detectability of such signals, it is important to be able to predict how atmospheres process volcanic inputs.  3) To take model planetary atmospheres, both perturbed and unperturbed by volcanism, and calculate synthetic transmission spectra.  Performing atmospheric retrieval on these synthetic spectra will identify the remote detectability of volcanism on Earth, and even around distant exoplanets.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Walker, J.C.G., Hayes, P.B. & Kasting, J.F. 1981. A negative feedback mechanism for the long-term stabilisation of Earth's surface temperature. Journal of Geophysical Research, vol. 86, pp.9776-9782.

Gaillard, F. & Scaillet, B. 2014. A theoretical framework for volcanic degassing chemistry in a comparative planetology perspective and implications for planetary atmospheres. Earth and Planetary Science Letters, vol. 403, pp.307-316., DOI: 10.1016/j.epsl.2014.07.009

Seager, S. & Sasselov D.D. 2000. Theoretical transmission spectra during extrasolar giant planet transits. The Astrophysical Journal, vol. 537, pp.916-921

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

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