Volcanic Processes

Volcano research at Durham is a natural progression of Jon Davidson's research originating in the (now defunct) Los Angeles Volcano Observatory (http://www.dur.ac.uk/j.p.davidson/petro.html). Projects on Cotopaxi Volcano (Ecuador) and Damavand Volcano (Iran) are ongoing, having been started at UCLA.

Magmas erupted at volcanoes serve as chemical (and to some extent physical) probes of the lithosphere and subjacent mantle. At Durham we use volcanic rocks to investigate the nature of the lithosphere. Graham Pearson and his students and postdocs have been using kimberlites and their cargo of xenoliths to reconstruct the lithospheric mantle in many parts of the world. In Indonesia Postgraduate student Heather Handley is looking at how the changing nature of the lithosphere along the arc influences magma compositions at widely-spaced volcanic centres.

We are interested in how magma systems behave - how magma differentiates and on what timescales. Such processes will not only control the compositions of erupted magmas, but will also influence the hazards posed by a given volcano. In short, whether a volcano passively erupts basalt at frequent intervals in low volumes per eruption (such as Hawaii) or whether it violently erupts large volumes of rhyolite less frequently (such as in New Zealand) is largely controlled on what happens as the magma makes its way through the lithosphere. This problem is the focus of a multi-disciplinary and multi-institution EC-funded project ("ERUPT" ). In ERUPT we are looking at well-dated volcanic rocks from 4 contrasting European volcanoes - Teide (Tenerife), Stromboli, Vesuvius and Campi Flegrei (Italy). The purpose is to use the rock components, crystals, glasses, melt inclusions, volatiles) to monitor how magmas have evolved - including the roles of crystal fractionation, magma mixing and contamination - where they have evolved in terms of the architecture of storage systems in the crust, such as size and depth of magma chambers, and how fast they evolved.

One of the most novel methods we are pursuing is crystal isotope stratigraphy (microsampling). The principle here is that as crystals grow in a magma system they record the changing conditions (pressure, temperature, composition). This approach is being used in ERUPT, and is also being used by;
1. NERC Post Doc Bruce Charlier, to track the sources and evolution of ignimbrites from the Taupo volcanic zone, New Zealand, and
2. Marie Curie Post Doc Catherine Ginibre, to track magma evolution at the Laacher See (Germany) and Parinacota (Chile).