Overview and assessment of the European lithium resources
Résumé
Driven by a global move towards renewable energy through the last decade, lithium has become a strategic metal due to its physical and chemical properties (e.g., lightest solid element and excellent conductor of heat and electricity) making it an excellent candidate for electrification of transport and green technologies such as Li-ion batteries and other energy storage devices. In this context, European interest in lithium mining and exploration has risen sharply and many countries are currently assessing their own mineral resources and reserves in order to secure their supplies. From this perspective, a geographically-based compilation of the European lithium hard-rock occurrences and ore deposits with their corresponding features (e.g., deposit types, Li-bearing minerals, Li concentrations) is presented. Accordingly, it appears that lithium is not particularly rare and is well represented and distributed through various deposit types related to several orogenic cycles from Precambrian to Miocene ages. Thus, 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 Czech Republic) and greisen mineralisation (Cligga Head, Tregonning-Godolphin, Meldon in UK; Montebras in France). Local exogenous processes such as hydrothermal and erosion transport may be also related to significant secondary Li-endowments including jadarite precipitation in the Jadar Basin (Serbia) but are rarely related to economic grade of lithium (e.g., Mn-(Fe) deposits, bauxite). Moreover, a systematic assessment of metallogenic processes in the Li endowment has been conducted and several relevant parameters have been identified and may offer exploration guidance for mining companies and governments. These parameters are: 1) a pre-existing Li-rich source related either to paleoenvironmental sedimentation conditions or a crustal anomaly; 2) presence of lithospheric thickening, which may reflect a favourable process to concentrate Li; 3) a regional or local extensional regime; and 4) existence of fracture sets acting as channel ways for exogenous processes.