New Insights into Graphite Deposits in Chisone and Germanasca Valleys (Dora-Maira Massif, Western Italian Alps): Scientific Advances and Applied Perspectives

Graphite is a critical raw material due to its pivotal role in the green transition; hence, there is a renewed interest in its exploration across Europe. The Chisone and Germanasca Valleys (Piemonte, IT) were home to significant graphite exploitation until the 20th century, owing to the widespread presence of graphite ore bodies hosted in the metasedimentary succession of the Pinerolo Unit in the Dora-Maira Massif (Western Alps). This contribution presents a renewed study on the geology, mineralogy, petrography, and geochemistry of graphite ores and their host rocks, employing OM, SEM-EDS, and BSE, μRaman, and ICP-OES/MS and INAA analyses. Mineralization occurs in two metasedimentary successions: (i) the Bourcet-type succession (meta-conglomerates and meta-sandstones intercalated with meta-siltstones/metapelites) and (ii) the Pons-type succession (meta-siltstones/metapelites intercalated with minor meta-arenites). Graphite occurs as (i) high-purity, fine-grained crystals dispersed within or concentrated in layers along the regional schistosity, or (ii) low-purity, coarse-grained crystals within shear zones. Based on crystallinity, three types of graphite were distinguished: high (Type I), intermediate (Type II), and poor (Type III) crystalline graphite, likely formed under different genetic conditions. The comparison of these findings has implications for future exploration and provides new insights into the metallogeny and geological evolution of the area.