October 2014 – Lab work, lab work and more lab work!

Having had a successful group meeting planning which samples our initial priority for Ar-Ar dating, cosmogenic dating and geochemical investigation are, lab work to prepare the samples began in earnest. For both the Ar-Ar and cosmogenic dating, large volume samples were collected, to give the best hope of picking enough crystals to get dates from, which meant that a trip to SUERC at East Kilbride was necessary to crush all the lavas and pumice samples to less than 2mm in size. Whilst preparing the samples for crushing (removing weathered edges for Ar-Ar and geochemical investigation) we also checked to ensure that the rocks were crystalline enough to allow for dating! (see picture). In 2 weeks we managed to crush more than 50 samples, which have headed back to Durham and Norwich for further preparation, involving sieving, various crystal concentration techniques and finally crystal picking by hand. Once the crystals have been picked they can be mounted into epoxy for major and trace element analysis, or they can be prepared for Ar-Ar (feldspar or groundmass) and cosmogenic (olivine or pyroxene) dating.

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A selection of different rock samples before being processed

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Examining rock samples using a hand lens

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Volcanic rock sample before crushing

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