Determination of Incompatible Trace Elements in Mantle Clinopyroxenes by LA-ICP-MS: A Comparison of Analytical Performance with Established Techniques |
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| Authors: | Paul RD Mason Kym E Jarvis Hilary Downes Riccardo Vannucci |
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| Institution: | NERC ICP-MS Facility, T.H. Huxley School, Imperial College, Silwood Park, Ascot, Berkshire, SL5 7TE, UK;Department of Geology, Birkbeck College, Malet Street, London WC1E 7HX, UK;C.N.R. Centro di Sudio per la Cristallochimica e la Cristallografia, Via Ferrata, 1, I-27100, Pavia, Italy |
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| Abstract: | Incompatible trace element abundances have been determined in mantle-derived clinopyroxenes by laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) in a comparative study with established microanalytical and bulk techniques. Individual clinopyroxene grains were sampled for the laser ablation study from sieved mineral separate fractions, from which similar mineral grains had been previously extracted for microprobe (SIMS) and bulk (INAA and ID-TIMS) analysis. Mineral grains were ablated with variable degrees of surface spatial resolution (50-200 μm) in order to maximise ICP-MS analyte count rates and to improve detection limits. A comparison of results from the different techniques reveals that for the most homogeneous samples LA-ICP-MS can achieve excellent levels of agreement with other techniques (10%) and good precision for most of the studied elements (1-5% RSD). Variations in calculated concentrations by LA-ICP-MS confirm inter- and intra-mineral heterogeneity determined by SIMS, reflecting changes in sample composition and texture. The long-term reproducibility of the technique is shown by the consistency of results for one sample analysed on thirteen occasions over a period of nine months. |
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| Keywords: | ablation laser ICP-MS clinopyroxène éléments en traces incompatibles comparaison de techniques |
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