Concentration of Ga, Ge, In and Fe in sphalerite as a function of deposit type – A meta-analysis

The statistical analysis of a comprehensive collection of analytical data compiled from the scientific literature shows that significant differences exist in the mean concentrations of Ga, Ge, In and Fe in sphalerite samples from different types of Pb-Zn deposits. A systematic trend is present in these mean concentrations: going from Mississippi Valley-type via vein-type to high-temperature hydrothermal replacement deposits, mean Ga and Ge concentrations decrease, while Fe and In concentrations increase. The same trend is observed going from Mississippi Valley-type via sediment-hosted massive sulphide to volcanic-hosted massive sulphide deposits. The two trends are virtually indistinguishable and seem to reflect a general increase in the magmatic contribution to the ore-forming process. While the exact geological controls remain unclear, this trend constitutes an important observation with immediate implications for the exploration for new resources of Ga, Ge and In.