Re-assessing the European lithium resource potential – A review of hard-rock resources and metallogeny

International audience ; Lithium, which is an excellent conductor of heat and electricity, became a strategic metal in the past decade due to its widespread use in electromobility and green technologies. The resulting significant increase in demand has revived European interest in lithium mining, leading several countries to assess their own resources/reserves in order to secure their supplies. In this context, we present for the first time a geographically-based and geological compilation of European lithium hard-rock occurrences and deposits with their corresponding features (e.g., deposit types, Li-bearing minerals, Li concentrations), as well as a systematic assessment of metallogenic processes related to lithium mineralization. It appears that lithium is well represented in various deposit types related to several orogenic cycles from Precambrian to Miocene ages. About thirty hard-rock deposits have been identified, mostly resulting from endogenous processes such as lithium-cesium-tantalum (LCT) pegmatites (e.g., Sepeda in Portugal, Aclare in Ireland, Läntta in Finland), rare-metal granites (RMG; Beauvoir in France, Cinovec in the Czech Republic) and greisen (Cligga Head, Tregonning-Godolphin, Meldon in the UK and Montebras in France). Local exogenous processes may result in significant Li- enrichment, such as jadarite precipitation in the Jadar Basin (Serbia), but they are rarely related to economic lithium grades such as in Mn-(Fe) deposits, or in bauxite. We also identified major common parameters leading to Li enrichment: 1) a pre-existing Li-bearing source; 2) the presence of lithospheric thickening, which may be a favorable process for concentrating Li; 3) a regional or local extensional regime; and 4) the existence of fractures acting as channel ways for exogenous processes. Furthermore, we point out the heterogeneity of knowledge for several orogenic settings, such as the Mediterranean orogens, suggesting either a lack of exploration in this geographical area, or significant changes in the orogenic .