Distribution and concentration of Indium, Germanium, and Gallium in epithermal deposits of Argentina: a meta-analytic approach

Abstract

In, Ga, and Ge are considered critical metals due to the risks associated with their supply and the growing demand driven by emerging technologies. This contribution presents a statistical analysis, based on non-parametric techniques, of mineralogical data obtained through electron microprobe analysis (EMPA) and laser ablation (LA-ICP-MS), compiled from scientific literature. The study focuses on the presence and concentration of In, Ga, and Ge in high (HS), intermediate (IS), and low sulfidation (LS) epithermal deposits, as well as in polymetallic epithermal (EP) deposits and porphyry-epithermal transition zones (P-HS) in Argentina. The results show significant differences among deposit types, with the highest concentrations of In, Ga, and Ge found in IS-type deposits, where minerals such as roquesite, sakuraiite, ishiharaite, omariniite, catamarcaite, and putzite act as the main carrier phases. EP deposits exhibit high concentrations of In and Ge associated with Sn-bearing minerals and sphalerite. Meanwhile, HS and P-HS deposits stand out for their Ge potential, with low In and Ga contents. The correlation matrix indicates a moderate positive correlation between In and Ga (r = 0.55), a negative association between In and Ge (r = -0.04), and no significant correlation between Ge and Ga. This study demonstrates the usefulness of statistical tools in identifying concentration trends of these critical metals across different types of epithermal deposits, representing a valuable tool for their future exploration.