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C313: VHALS: Volcanic sources of Halogens And their cLimate impactS (Lead Supervisor: Alexander Archibald, Chemistry)

Supervisors: Alexander Archibald (Chemistry), Marie Edmonds (Earth Sciences) and John Maclennan (Earth Sciences)

Importance of the area of research:

Volcanic eruptions are a key mechanism for recycling material in the Earth system - providing feedbacks between the atmosphere-lithosphere.  One important but overlooked cycle that volcanism plays a role in is the recycling of halogens, which play a duplicitous role in the environment; essential elements for life yet toxic and extremely harmful. One of the greatest threats that halogens pose is the depletion of the stratospheric ozone layer (our planets natural sun-block). The source of the halogens responsible for this ozone loss are predominantly anthropogenic (Montzka et al., 2011), recent evidence (Black et al., 2014) suggests that fluxes of halogens from volcanoes could have far surpassed these man made emissions during periods of the Earth’s deep past, with consequences for life. Understanding the role of volcanic sources of halogens and the impacts they have on climate and the habitability of the planet is crucial for our understanding of past and future environmental change.

Project summary:

VHALS will use state of the art chemistry-climate models developed at Cambridge and confront them with new estimates of halogen outputs from the Siberian traps and other large igneous provinces to understand for the first time the detailed climate impacts of volcanic emissions of the major halogens, chlorine and bromine, under a range of different climate states. The outcomes of the model will be tested against innovative sources of geochemical evidence for halogen emissions and increases in UVB flux to the surface of the Earth.

What the student will do:

The student will work alongside both Earth and atmospheric scientists. Geochemical data extracted from lavas in a range of flood basalt provinces will constrain a series of model experiments that will probe volcanic halogen emissions. The student will learn how to perform these model experiments using a state of the art chemistry-climate model. This model is developed in Cambridge with collaboration from scientists at the UK Met Office and other academic institutes and is linked to the UKs major contribution to the IPCC assessment report.  The outcomes of the model will be tested using a range of innovative geochemical approaches aimed at reconstructing the flux of UV radiation reaching the Earth’s surface.

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.


Black et al., 2014, “Acid rain and ozone depletion from pulsed Siberian Traps magmatism.” Geology 42(1).

Beerling et al. 2007, "The stability of the stratospheric ozone layer during the end-Permian eruption of the Siberian Traps." Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences 365.1856: 1843-1866.

Montzka et al., 2011, “Global Ozone Research and Monitoring Project”. Report No. 52. World Meteorological Organization. pp 1–112.

 Follow this link to find out about how to apply for this project.


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