Sardinia's Mineral Resources Database Update: New Exploration Guides for Identifying Critical and Strategic Raw Materials for Decarbonization and Ecological Transition

The European Union's strategic agenda for a decarbonised and self-sufficient economy culminated in the Critical Raw Materials Act (CRMA, 2024), which defined Critical and Strategic Raw Materials (CRMs and SRMs) essential for technological development and economic resilience, while being subject to high supply risk. Within this framework, the PNRR Geosciences IR project of ISPRA (Italian Institute for Environmental Protection and Research) is developing a series of thematic databases. This thesis presents the new Metallogenic Database of Sardinia, the foremost mining region of Italy, designed to support the exploration of CRMs fundamental to the energetic transition. A comprehensive, relational geodatabase was built using PostgreSQL-PostGIS and QGIS, integrating over 630 mineral occurrences, deposits, and active mines. The schema combines descriptive, compositional, structural, and technical data, with a dedicated focus on CRMs. The work valorised legacy information from the historical Metallogenic Maps of Sardinia (1978, 2008) and the reports of the former Sardinian Mining Bureau (EMSA, 1980s), integrating them with recent scientific literature, targeted field campaigns, and new laboratory analyses. The database structure is inherently designed to schematise mineralisation models and facilitate predictivity models. The iterative, data-driven methodology is illustrated through representative case studies, each investigated with specific techniques based on the dominant ore control: the structures of mixed-sulphides skarn and fluorite-barite hydrothermal veins of the Rosas-Orbai district (SW Sardinia) and the Fluminese district (W Sardinia); the geochemistry and geochronology of Mo-W-LREE greisen and fluorite veins of the Su Laccheddu-Giacone system (N Sardinia); the vertically-zoned fluorite-barite veins of the Silius deposit (SE Sardinia). These studies provided new mineralogical and structural data, which were iteratively fed back into the database to refine the genetic models. Finally, the database was applied to regional-scale Mineral Prospectivity Modelling (MPM) for skarn-type deposits in central and southern Sardinia. A fuzzy logic-based approach, integrating proximity to intrusions, reactive lithologies, and faults, generated a prospectivity map validated by ROC analysis (AUC = 0.845). This demonstrates the database's predictive power, successfully distinguishing skarn-bearing from barren cells and identifying high-priority exploration targets. The work establishes a robust, transferable framework for modern mineral resource assessment, directly supporting Europe's strategic autonomy goals.