“Differentiation of mantle-derived magmas from beneath Grenada, Lesser Antilles”
1) The Twitter challenge: Your PhD in 140 characters
Unravelling the mystery of how magma chambers work by making synthetic replicas of volcanic rocks – Caribbean fieldwork is a bonus!
2) How are you pushing the frontiers of science?
I am attempting to recreate the conditions found in a magma chamber, albeit on a very small scale using a machine called a piston cylinder. I heat tiny packets of synthetic rock powder to around 1300ºC and put them under a pressure equivalent to being 30km depth below the Earth’s crust. If what comes out mirrors what I see in natural volcanic rocks, I know I am on the right track to resolving the processes and conditions at play beneath certain types of explosive volcanoes.
3) What part of your work do you enjoy the most?
Definitely the variety. Running piston cylinder experiments is quite practical; sample preparation involves using a lathe, a micro-welder and lots of heavy lifting! In contrast, to analyse the run products, I use a plethora of microanalytical techniques and often spend long hours in front of spreadsheets crunching the data. No two days are the same.
4) What’s the most challenging aspect?
The fact that the effort expended does not correlate with net progress. Lab work is timely and physically demanding, so when an experiment goes wrong it’s hard not to take it personally. If nothing else, doing a PhD has taught me how to deal with failure!
5) Favourite piece of equipment
The unsung hero of the analytical lab is the scanning electron microscope (SEM). It uses a focused beam of electrons, rather than light, to create an image of a sample. Not only does this allow me to magnify my sample by up to ~4,000 times, but it can also provide near-instantaneous compositional data about the rock or experimental run product in question. In Back Scattered Electron (BSE) mode, the brightness of the image is proportional to the atomic mass and so mineral phases can easily be differentiated.
6) Best travel perk of the job
I’ve been incredibly lucky in that my PhD has taken me to lots of exciting places (Australia, Greek islands, Didcot Parkway), but without a doubt the highlight was a three-week stint of fieldwork in the Lesser Antilles. My main aim was to bring back igneous cumulate xenoliths (pieces of the magma chamber wall that were ripped off and brought to the surface during explosive eruptions) from the volcanic islands of St. Vincent and Grenada, and I also took samples from Grenadines archipelago. Very little public transport was available so we had to charter a yacht, all in the name of science!