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A potential reserve of critical raw materials in the Sabatini geothermal field, Italy

Francesca Godono 1, Federico Rossetti1, Ahmad Rabiee1, Matteo Furlan2, Luca Aldega3, Andrea Orlando4, Fabio Bellatreccia1, Sandro Conticelli5,6, Guido Giordano1

  • Affiliations: 1Dipartimento di Scienze, Università degli Studi Roma Tre, Rome, Italy; 2Institute of Geological Sciences,University of Bern, Bern, Switzerland; 3Dipartimento di Scienze della Terra, Università degli Studi di Roma La Sapienza, Rome, Italy; 4Istituto di Geoscienze e Georisorse, CNR, Florence, Italy; 5Dipartimento di Scienze della Terra, Università degli Studi di Firenze, Florence, Italy; 6Istituto di Geologia Ambientale e Geoingegneria, Area della Ricerca Roma 1, Montelibretti (RM), Italy

  • Presentation type: Talk

  • Presentation time: Tuesday 14:30 - 14:45, Room S160

  • Programme No: 4.1.2

  • Theme 4 > Session 1

Abstract

The Pleistocene (~800-70 ka) Sabatini Volcanic Complex hosts a geothermal field that has recently been the focus of renewed research interest to explore potential lithium resources in hydrothermal brines in Italy. However, the metasomatic calcsilicate (skarn) rocks hosting such brines may also have economic importance, potentially hosting critical raw materials. Using borehole core and cutting samples (ENEL-SH2 well; depth= 2498 m), we defined the mineral assemblage of the skarn rocks and the in-depth distribution of the REE-bearing minerals (vesuvianite, garnet, titanite) to estimate the potential reserve, integrating microtextural investigations with XRD, EMPA and LA-ICPMS techniques. Boron-rich vesuvianite (wiluite) is the most abundant mineral within the depth interval of -1400 to -1650 m, with an average modal content of 22 vol%. Vesuvianite exhibits an average B content of ~7500 ppm, high total REE oxides (TREO) content, and an average U content of 113 ppm. Using the available geological reconstruction from drilling and residual gravity modeling, we estimate a total (minimum) volume of the vesuvianite skarn of ~0.5 km3. These preliminary results suggest the economic importance of the hydrothermal mineralization associated with the Sabatini geothermal field as a potential REE reserve and strategic repository for critical raw materials in Italy.