Assessing United States gallium and germanium resources in basin-hosted deposits – The good and bad

Basin-hosted Zn-Pb deposits, including MVT and clastic-dominated (CD or “Sedex”) Zn-Pb deposits are major sources of Zn and Pb, as well as other critical elements. We examined available whole rock and sphalerite chemistry data to understand the apparent variation of Ga and Ge among major current and historical districts of the United States (US). Robust data from the Central Tennessee district demonstrate Ga and Ge enrichment. Limited historical data suggesting anomalous concentrations in the nearby Central Kentucky and Illinois-Kentucky districts imply a possible similar fluid chemistry for Ga and Ge transport. The deposits of the Red Dog district, Alaska, also have anomalous concentrations of Ge, but not Ga. Our work demonstrates the utility of whole rock geochemistry to identify potential critical element resources. Highly qualitative estimates, based on geochemical data, indicate that these basin-hosted deposits contain Ge (and in the case of Central Tennessee, Ge and Ga) resources of potentially sufficient size to provide decades of resources if appropriate domestic processing is developed.