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E431: Powering the nation: The Icelandic crustal heat balance (Lead Supervisor: John Maclennan, Earth Sciences)

Supervisors: John Maclennan (Earth Sciences) and David Neave (Universitat Hannover

Importance of the area of research:

Geothermal heat sources play an important role in the provision of energy in Iceland. In future, this energy may also power the UK. Recently, attention has turned to deep drilling, in search of supercritical fluids (see iddp.is). The source of the geothermal heat is cooling and crystallisation of magma in the Icelandic crust. The last few years have seen improving petrological barometry of the depth of magma chambers and updated geophysical imaging of the structure of the crust.  It is now possible to develop robust models of the distribution and magnitude of magmatic heat sources under Iceland. This work has implications for the extraction and sustainability of geothermal production in Iceland.

Project summary:

As magma is stored in magma chambers it cools and crystallises. An important sink for this specific and latent heat source is the heating of water in hydrothermal systems close to the chamber. While it has long been known that crystallisation takes place at near-Moho depths under Iceland, the most up-to-date thermal models of the Icelandic crust involve either only crystallisation at shallow levels or ignore the effects of hydrothermal cooling entirely. Improved petrological thermo-barometry and better understanding of the crystallisation behaviour in individual volcanic systems means that petrology provides crucial constraints for any thermal model of the Icelandic crust. The goal of this project is to link this petrological understanding with geophysical observations through a thermal model.

What the student will do:

The student will carry out field work in Iceland to sample basalts and carry out petrological barometry. They will compile a database of estimated crystallisation temperatures and pressures and model the relationship between temperature and extent of crystallisation using available parameterisations. With knowledge of the compositional structure of the crust it is then possible to relate geophysical observations to likely temperatures. They will then make a thermal model of crystallisation and hydrothermal cooling to match the inferred temperature distribution.

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:

Schmeling, H, & Marquart, G., 2008, Crustal accretion and dynamic feedback on mantle melting of a ridge-centred plume: the Iceland case, Tectonophysics, 447, pp 31-52, doi.org/10.1016/j.tecto.2006.08.012

Maclennan, J., et al., 2001, Crustal accretion under northern Iceland, Earth and Planetary Science Letters, 191, pp 295-310. doi.org/10.1029/2000JB000142

Maclennan, J., et al., 2005, Cooling of the lower oceanic crust, Geology, 33, pp357-366, https://doi.org/10.1130/G21207.1

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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