liThium and cRitical metals in hArd rocks: iNSights From geoenvironmentAl model and socIo-economics tRends – TRANSFAIR

Rare metals (e.g. Li, Ta, Sn) are critical components for the renewable energy technologies. In Europe, a significant part of the resources issues from rare-metal granites and pegmatites (RMPG), especially those known in the Variscan belt remnants, such as the French Massif Central (FMC) and Iberian Massif. In order to achieve the green high-technology revolution, a sustainable European supply of Li and Ta needs the exploitation of the European RMPG deposits. However, the economic, environmental and societal impacts of such exploitation must be clarified. Furthermore, the geological processes involved in the genesis of such peculiar magmatic rocks and their extreme metal enrichment, e.g. the metallogenic model, remain poorly understood. This makes difficult the prediction of favourable areas for new discoveries.
The TRANSFAIR project is a stimulating consortium that gathers a transdisciplinary expertise from geosciences to human sciences. It will provide a comprehensive metallogenic model for RMPG, enhancing district to deposit-scale mineral prospectivity mapping. To reach these objectives, TRANSFAIR will rely on two typical examples known in the FMC and Iberia, common learning fields for all the project activities. Based on recent results, TRANSFAIR propose to study the hypothesis of the RMPG origin from partial melting of Li-rich sedimentary source(s), combining innovative melting experiments and the characterization of natural objects following several approaches (petrology, geochemistry and geochronology). Ascent and emplacement processes, key parameters to explain the locations of the deposits, will be better constrained thanks to a coupled work of experimental petrology and numerical modelling. These results will be compared to natural case studies by a 3D understanding of the tectonic and structural contexts of ascent and emplacement of the deposits, reached by the acquisition of new geophysical and field data. Geochemistry (including stable and radiogenic isotope systematics) and geochronology will draw a better knowledge of the magmatic history of RMPG fields, from partial melting to emplacement of barren rocks and ore deposits. The integration of all these results will build predictive maps of favourable areas for RMPG.
In the context of a significant increase of the needs for Li, which will lead to a strong increase of mining activities. TRANSFAIR will also draw the sociologic, economic benefits and disadvantages of new operations of RMPG in Europe and the strategy for societal engagement for renewed mining activities in Europe. Thus, TRANSFAIR will decipher the economic parameters linked to the valorisation of European RMPG by an econometric approach. Based on life cycle analysis, environmental impacts of these domestic operations will be compared to the actual global market. At last, levels of potential acceptability of mining projects in France, Portugal and Spain will be evaluated determining the concerned territories profiles, mapping stakeholders and adapting the social risk index. Simultaneously, TRANSFAIR will assess imaginaries linked to lithium, actually essential for the energy transition, making the link with the cartography of the geological potential issued from the project.
As an answer to the actual needs of critical metals, TRANSFAIR will bring solutions towards better knowledge and valorisation of the European potential of RMPG, giving the keys both for a more efficient exploration, but also the bases for a better understanding between all stakeholders (citizens, public institutions and industries).