More volcano fun!

Hello

Once again I am back in Colima ready for another month of field work, lab work and winter warmth! Although this time I'm going to take a few days off and see some sights.

It's great to be back out here. The pace of life is so slow and relaxed that you can't help but get sucked into it. I've spent the entire day sitting about drinking freshly squeezed juice and cups of coffee while watching the world pass by in a semi-comatosed state. That might have something to do with jet-lag and arriving in Colima at 1am having been travelling for over 24 hours! I know some of you had much longer journeys to contend with before Christmas, but I reckon I can still moan about it after a train, 2 planes and a bus journey!

So, since my trip to Mexico last year, I've been busy in the labs working on the tephra samples I collected, and the samples I already had. In order to analyse the samples for their whole-rock geochemistry I had to clean them of thousands of years of dirt which they've been sitting in, which involved scrubbing each piece with a toothbrush and using an ultrasonic bath to vibrate the dirt off them. With 40 odd samples, you can imagine how long that took me! Once cleaned I left them for a couple of days in an oven to dry them, then crushed them to a very fine powder which has been sent away for analyses. It's crazy, but it's actually cheaper sending them to the States than analysing the

m ourselves in Leeds!

I've also been doing lots of electron microscope (SEM) and electron microprobe analyses which gives me the chemical make up of individual crystals - very useful for looking at how the chemistry of the magma has changed. Minerals have growth rings like trees, and by analysing each growth ring you can see how the magma has evolved, and whether a new batch of magma has been injected to the chamber.

Sorry I know the picture is a little boring but this is an image from the SEM of the growth rings in minerals. The biggest mineral is about 1mm long. The rim of the dark core is wiggly because the crystal started melting because of a new batch of magma which would increase the temperature. The next ring in really light, then gradually darkens with each phase of growth towards the rim. As crystals grow they deplete the magma in certain elements - Magnesium, Iron and Sodium first, then Aluminium, Potassium and Calcium, and the magma composition changes. The light to dark growth in the large crystal shows this with the gradual darkening in colour.

Sorry, lesson over for today!

I also took the opportunity to go on a summer school in Iceland for 10 days. What an incredible country! It was fantastic, although I have to admit, a part of me was disappointed not to see an active eruption! As daft as it sounds, I kinda had it in my head that with Iceland commonly being called the Land of Ice and Fire, and the fact that it sits of the boundary of 2 plates which are pulling apart, there would be lava fountains and flows all over the place…..

So here I am back in Colima, looking forward to seeing more eruptions!!