Critical metals in sphalerites from Belgian MVT deposits

Belgium hosts a series of well documented low temperature, carbonate hosted, lead-zinc veins and lenses clearly categorized as MVT deposits. This paper revisits the distribution of trace elements in sphalerites from Belgian deposits with a special focus on Ge, Ga and
In. By comparing with a database of worldwide deposits, this paper shows that Belgian sphalerites do not display a classical substitution pattern involving Cu+. Instead, multivariate analysis points towards similarities with the Tres Marias deposit in Mexico, although the explanation of coupled substitution with Fe++ does not seem to apply in the present case. From the limited set of sphalerites analysed in this paper, the following rithmetic means are obtained: m(Ge) = 302 ppm, m(Ga) = 2.2 ppm and m(In) < 0.06 ppm. These average values should not hide the fact that a wide variability does exist from one deposit to the other and within zoned colloform sphalerites of the same deposit. Further nd systematic work is required to better evaluate the resource and understand the mechanisms responsible for Ge incorporation into sphalerite.