Accurate electron probe microanalysis of key petrogenetic minor and trace elements in Cr-spinel Domínguez Carretero, Diego Llovet, Xavier Pujol Solà, Núria Villanova-de-Benavent, Cristina Proenza, Joaquín A. Electron probe microanalysis Trace elements Cr-spinel Ophiolitic chromitites Data aggregation This research was financially supported by the Spanish grant PID2023-147788OB-I00 funded by MCIN/AEI/10.13039/501100011033 to JAP and CVdB, and by a “Ayudas predoctorales 2020” grant to DDC (number PRE 2020-092140 PhD) from the Spanish Ministry of Science, Innovation and Universities. This paper has been produced within the framework of the MinResET (Mineral Resources for the Energy Transition) research group (2021-SGR-00239, Catalan Agency for Management of University and Research Grants-AGAUR). The trace element composition of Cr-spinel is paramount for interpreting the petrogenesis of a large group of mafic to ultramafic rocks. Although laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has proven to be very useful for the determination of trace element abundances of Cr-spinel, the characterization of Cr-spinel grains that are inhomogeneous over micrometer length scales requires the use of techniques that provide a better spatial resolution than LA-ICP-MS. In this work, we develop a protocol for the determination of trace and minor elements in Cr-spinel by electron probe microanalysis (EPMA) using the software provided by the manufacturer. The optimized analytical conditions (25 kV accelerating voltage, 900 nA beam current, 60–480 s peak counting times, aggregate spectrometer data) allowed us to achieve detection limits (3 ) in the range 4–26 ppm with relative analytical precisions (2 ) in the range 1–3 % for all analyzed elements (Ti, V, Mn, Co, Ni, and Zn), except for Sc and Ga, for which the precision was much lower (36–46 %). The developed methodology was applied to the analysis of Cr-spinel grains from the Mayarí-Baracoa Ophiolitic Belt (eastern Cuba), in correspondence with previous LA-ICP-MS analyses, which were used to assess the reliability of the EPMA results. The root mean square percentage deviation (RMS) between the EPMA and LA-ICP-MS data was in the range 4.7–22.5 % for Ti, V, Mn, Co, Ni, and Zn, while for Ga the RMS value was 32.5 %. For Sc, the RMS value was much higher (171 %), despite the low detection limit achieved (4 ppm) for this element. Our results indicate that the trace element composition of primary Cr-spinel obtained by EPMA can be readily used, except for Sc, to constrain petrogenetic information on chromitites in a reliable way. 2025-02-10T11:00:32Z 2025-02-10T11:00:32Z 2025-02-20 journal article D. Domínguez-Carretero et al. Chemical Geology 674 (2025) 122579. https://doi.org/10.1016/j.chemgeo.2024.122579 https://hdl.handle.net/10481/102145 10.1016/j.chemgeo.2024.122579 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier