Major and trace elements in meimechites – rarely occurring volcanic rocks: developing optimal analytical strategy

Published on 2018-09-10T15:19:02Z (GMT) by
<div>The determination of the chemical composition of meimechites – which are unique and rarely occurring ultra-high MgO igneous rocks – can be complicated due to their porphyric structure, the presence of acid-insoluble minerals, and wide variation of major and trace element contents. In the present study the optimal analytical strategy based on a combination of X-ray fluorescence (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) methods was suggested for the determination of the elemental composition of meimechites. The preparation of glass beads using a lithium tetraborate and metaborate mixture proved to be suitable for the XRF determination of major oxides. <br></div><div>A comparative study of the sample decomposition procedures for the determination of trace elements by ICP-MS clearly showed that fusion with lithium metaborate was the most appropriate sample preparation technique for complete digestion of meimechites. The open beaker HF-HNO3-HClO4 acid digestion was insufficient because the results for Nb, Ta, V, Zr, Cr and Hf were underestimated by 20–80% compared to those determined using the fusion method due to the presence in the rock<br></div>samples of acid-resistant accessory minerals. It is shown that using analytical data from acid digestion may lead to erroneous interpretation of geochemical data.

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Pashkova, Galina V.; Panteeva, Svetlana V.; Ukhova, Natalia N.; Chubarov, Victor M.; Finkelshtein, Alexandr L.; V. Ivanov, Alexei; et al. (2018): Major and trace elements in meimechites – rarely occurring volcanic rocks: developing optimal analytical strategy. Geological Society of London. Collection.