Serpentine carbonation could provide a safe, and environmentally friendly, opportunity to store the amount of anthropogenic CO₂ emission necessary to meet the Paris Agreement target and limit global warming to a safe level for humanity. Mineral carbonation relies on the reaction of CO₂ with cations abundant in ultramafic rocks (e.g. Mg²⁺) to form carbonate minerals (\citealp{Kelemen_2019}). Serpentinites are an ideal starting material because they are abundant on or near the Earth’s surface and are rich in Mg²⁺, which is required to form carbonates, primarily magnesite (MgCO₃) that traps CO₂ (\citealp{Lackner_1995}). This process stores CO₂ in a solid state with no risk of release and has large storage capacity. Even if this technique is promising, it is at a lower stage of readiness and is yet to be applied at the industrial scale.

The Ligurian ophiolites (Italy) host several magnesite deposits that formed when deep CO₂ was injected into serpentinite lenses through regional faults at 100-200°C and depths of 1-2 km (\citealp{Rielli_2022}, \citealp{Boschi_2009}). These deposits effectively resemble the in-situ storage of CO₂ by “natural pilot plants” active millions of years ago, where seemingly the conditions where fine-tuned to best sequester CO₂. Thus, they provide a fast lane for understanding the best conditions for serpentinite carbonation.

The PRIN 2022 PNRR STORECO2 project (granted by the European Union—NextGeneration EU) aims to understand these conditions through a geochemical, petrological and mineralogical study of the Castiglioncello magnesite deposit (Tuscany, Italy). Developing a deeper understanding on carbonation processes through the study of natural analogues, discussed in this work, we will able also to predict what to expect when CO₂ is injected into serpentinites.