Research Interests

Current research interests include:

How does gas escape from highly-viscous, silica-rich magma?

Tuffisite veins are formed by venting of gas and ash through fractures in and around conduits and lava domes, as seen in my 2012 BBC2 film from Cordon Caulle. They are thought to be key eruption controls, mediating the escape of gas from highly-viscous magma, and responisble for earthquake triggering in silicic eruptions. However, they are also known to seal up, preventing pressure release and driving explosions. Little is understood about the timescale and mechanism of tuffisite formation, the amount of gas they can deliver, and how rapidly they become blocked and sealed. We are using field and micro-textural methods to characterise the nature of tuffisite veins from a depth of hundreds of metres in conduits up to the surface. Measurement of volatile species is proving particularly useful as a tool to reconstruct pressure changes during vein venting and blockage. This work is supported by the Royal Society and NERC and carried out in collaboration with scientists at the University of Mainz, McGill University, Victoria University of Wellington, and the Diamond Light Source.

In a new partnership, supported by a Royal Society International Exchange grant, I am teaming up with Dr Mike Heap (Université de Strasbourg) and Fabian Wadsworth (University of Munich) to characterise the permeability evolution of tuffisite and model compaction processes.

Can we exploit magmatic heat to generate unprecedentedly powerful geothermal energy?

In 2009 the Icelandic renewable energy company Landsvirkjun accidentally drilled into rhyolitic magma at 2.1 km depth within Krafla, in northern Iceland, briefly creating the world's most powerful geothermal borehole. This unexpected discovery may pave the way to a new generation of geothermal energy production, directly tapping the vast reserves of energy stored in and around magma intrusions in the crust. I am involved in the Krafla Magma Drilling project, which has recently received funding to support further drilling into magma in 2017. The objective of the new drilling will be to characterise the nature of the stored magma and the surrounding rocks. My research contribution is to help investigate the reaction of stored magma to drilling (e.g. whether it froths up or fragments), in order to assess the safety of drilling.

I am also studying fossilised magma-geothermal interfaces preserved in eroded volcanoes in Iceland, New Zealand and elsewhere, to assess the potential for prolonged heat extraction from intrusions. This is partly facilitated by a Catalyst grant, led by Dr Ben Kennedy (University of Canterbury, New Zealand), and also involving Liverpool, Strasbourg, Mighty River Power, and Victoria Univeristy of Wellington.

What controls the explosivity of sub-ice eruptions?

A large proportion of the world's volcanoes are at least partly ice-covered, most notably in Iceland, and this makes them more hazardous, as magma interacts explosively with meltwater and rapid ice melting generates powerful floods. We know remarkably little about this type of eruption, for example whether Icelandic ash plumes such as Eyjafjalljokull 2010 are driven by dissolved volcanic gases or interactions with meltwater. AXA postdoctoral research fellow Jacqueline Owen is investigating what controlled the powerful 1918 eruption of Katla volcano in Iceland, having completed an in-depth study of the largest known sub-ice rhyolitic eruption, from nearby Torfajokull.

What controls lava flow advance?

Lava has a broad range of compositions, from low-silica basalt to high-silica rhyolite. Dramatic differences in viscosity (by several orders of magnitude) mean that basaltic lavas can advance hundreds of times more rapidly that rhyolites. However, there appear to be common processes controlling lava advance and the evolution of flow fields. We recently made the first detailed observations of an active rhyolitic lava flow, at Cordon Caulle in Chile, and discovered that slowly-moving rhyolite (1-3 metres a day) behaves in a very similar way to more fluid and commonplace basalts. In ongoing research, supported by the Royal Society and NERC, we are characterising and contrasting rhyolite lava advance at Cordon Caulle with basaltic flows at Bardarbunga, Iceland and Etna, Italy.

How does magma crystallise, degas and vesiculate?

The growth of crystals and bubbles in magma, and the loss of dissolved gases, has a transformative effect on its behaviour. For example, crystallisation mediates crust formation in lava flows, vesiculation controls the formation of magmatic foams during explosive events, and degassing determines whether explosive or effusive eruptions occur. We are using two complimentary approaches: experimentally growing crystals and vesicles in magmas in the lab to measure rates and patterns of growth, and characterising crystal and vesicle populations in ancient rocks to reconstruct what happened. Similarly, experimental degassing compliments measurement of dissolved gases in natural volcanic glasses. This research is supported by the Royal Society and AXA.

Thermal analysis of volcanic rocks and magmas

Thermal analytical techniques involve heating volcanic rock samples to magmatic temperatures (700-1200 °C) and characterising changes to their physical and chemical state. We use three approaches in my lab:

In thermogravimetric analysis, volatile species are released from samples on heating, revealing concentrations and speciations of magmatic gases, identification of mineral phases, and timescales of diffusive degassing. Recent papers have addressed obsidian hydration in Iceland, degassing in the AD79 eruption of Vesuvius, the emplacement of ignimbrites, and the nature of some of the youngest kimberlitic magma erupted on Earth.

Differential scanning calorimetry involves monitoring shifts in the thermal properties of samples during heating and cooling, and allows characterisation of crystal growth/resorption, along with the glass transition. Recent papers look at crystallisation processes in basalts and ongoing work is addressing the cooling rate of glasses as well as crystallisation kinetics.

Finally, hotstage microscopy involves visual monitoring of textural changes within samples at temperatures up to 1500 C. We are using this technique to investigate the growth of vesicles and crystals within magmas, as well as their collapse and resorption, together with the sintering of both natural and synthetic glasses. Recent papers have dealt with crystallisation of basalts and vesiculation of rhyolites, and ongoing work looks at sintering, basalt vesiculation and crystallisation of rhyolites.

Our thermal lab, thanks to funding from the Royal Society, NERC and Lancaster University, is equipped with a Netzsch STA449C Jupiter, a TA Instruments Q600 SDT hyphenated with a Hiden HPR20 exsolved gas analyser, and a Linkam TS1500 hotstage linked to a Zeiss Axioscope A1 petrological microscope.

Research Grants

2016 Royal Society International Exchange grant, PI, £12k, Volcanic valves. Partnership with Dr Mike Heap of Université de Strasbourg.

2016 ANR Grant "LAVA", led by Andy Harris (Clermont-Ferrand), project partner.

2015 Royal Society University Research Fellowship Extension, PI, £410k, Conduit processes in recent Chilean rhyolite eruptions.

2013 AXA Postdoctoral Fellowship, PI, £110k, Understanding Katla, Iceland’s notorious and restless volcano: Lessons from 1918.

2012 Royal Society Equipment Grant, PI, £50k, Differential Scanning Calorimetry.

2011 NERC small grant NE/I016414/1 co-I, £65k, “Quantifying degassing-driven crystal growth in basaltic lavas”.

2010 Royal Society University Research Fellowship, PI, £563 k, 2010-2015.

2009 NERC standard grant NE/F018010/1, Co-I, £370 k, “The effects of degassing and effusion rate fluctuations on the evolution of basaltic flow fields”.

2008 NERC New Investigator grant NE/G000654/1, “Volatile degassing from magma: Insights from eruptions under Icelandic glaciers”, PI, 2008-2010, £6k.

2007 NERC Research Fellowship NE/E013740/1, PI, £260k.

2006 NERC standard grant NE/D012910/1, researcher co-I, £550 k (£21k to Lancaster), “Fracture mechanics of dome lava”.

2004 Leverhulme Early Career Research Fellowship, Lancaster-UCL, PI, £90 k.

Current Teaching

LEC.478/384 Physical Volcanology

LEC.474/377 Geological Hazards

LEC.477/378 Global Change and the Earth System

LEC.321 Glacial systems

LEC.171 The Earth's Interior

LEC.103 Environmental Processes and Systems

My Role

Reader in Volcanology, former Royal Society University Research Fellow

Director of Studies, MSc in Volcanology and Geological Hazards

PhD Supervision Interests

Magma-geothermal system interactions in Iceland | Tuffisite veins and silicic conduit dynamics | Silicic lava emplacement | Volcano-ice interactions | Experimental crystallisation and vesiculation of magma |