Investigating the 3D mineralogical and textural variability of lithium-bearing minerals in LCT pegmatites using spectral computed tomography

Many chemical elements are critical for our green energy transition (e.g., for the production of lithium-ion batteries). Many of these criticalelements are associated with a type of magmatic deposit: lithium-cesium-tantalum (LCT) pegmatites. These LCT pegmatites have been studiedin detail, but different schools of thought still exist on the formation conditions [1, 2]. Especially the potential role of the fluxing components inthe concentration of these critical elements remains a puzzling phenomenon [3]. A detailed three-dimensional (3D) characterization of LCTpegmatites is paramount in improving our knowledge of their formation history. Applying a methodology where a 2D microbeam imagingtechnique-based automated mineralogy system is combined with X-ray computed tomography (μCT) allows to investigate the 3D mineraldistribution throughout individual pegmatite dykes [4]. We present the identification of lithium-bearing minerals in 3D using (spectral) X-raycomputed tomography. It will allow to pinpoint the crucial stages that enable critical element mineralization during LCT pegmatite formation.Ultimately this will allow the verification of proposed petrogenetic models and experimental simulations [5, 6]. [1] London (2018). Ore Geology Reviews 101, 349-383. [2] Simmons & Webber (2008). European Journal of Mineralogy 20(4), 421-438. [3] Linnen, Van Lichtervelde & Černý (2012). Elements 8(4), 275-280. [4] Buyse, Dewaele, Boone & Cnudde (2024). Geologica Belgica 27(1-2), 1-14. [5] London & Morgan (2017). Journal of Petrology 58(5), 1005-1030. [6] Koopmans, Martins, Linnen, Gardiner, Breasley, Palin, Groat, Silva & Robb (2023). Geology 52(1), 7-11. Florian Buyse has received funding from Research Foundation Flanders (FWO) for a short study stay abroad at UPPA-DMEX, France under projectnumber K254124N and from the European Union’s Horizon Europe research and innovation programme under grant agreement No 101131765(EXCITE) for Transnational Access conducted at UPPA-DMEX, France. Figure 1. Differentiation between spodumene, quartz-spodumene intergrowth and K-feldspar using spectral computed tomography.