LA-ICP-MS and EMP relationships in pyrite grains from Barberton Greenstone Belt, South Africa: An attempt for quantification

Abstract

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) count per seconds (cps) results were tested for quantification, using the same spot analyses of Electron Microprobe Analyses (EMP) in weight percentage (wt. %); they were obtained from selected pyrite grains from Sheba, New Consort, and Fairview gold mines of the Barberton Greenstone Belt (BGB). Theoretically, data obtained from the same pyrite grains, using two different techniques must represent, to some extent, the same chemical composition, but not exclusively the same values. This comes because they applied to the same spots, and within the same pyrite grains. Yet, the results obtained in this study of the two techniques are not directly comparable. Graphical and statistical techniques were also applied to depict any existing relationships. However, all do not indicate any kind of similarity in the distribution of major or trace-elements in the pyrite of both datasets. The results of this study imply that the obvious correlations between data of the two techniques for matching spots are failed by several factors (spot size, zoning, heterogeneity, etc.), which are negatively influencing any direct standardization procedure of LA-ICP-MS data based on EMP results. Key words: Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), electron microprobe, Barberton greenstone belt, pyrite, standardization.