Ternary diagrams showing the compositions of cassiterite from pegmatites of the FA field. (a-b) Nb + Ta versus Sn + Ti versus Mn + Fe diagram (apfu) comparing (a) the compositions of cassiterite from different pegmatite types, and (b) the compositions of early, low-CL, cassiterite with late, high-CL, cassiterite from the Bajoca petalite-rich pegmatite. Compositions are based on electron microprobe analyses from this study (filled symbols) and the literature (empty symbols; Roda-Robles et al., 1999; Vieira 2010). The substitution line (Fe,Mn)²⁺ + 2(Nb,Ta)⁵⁺ = 3(Sn,Ti)⁴⁺ is from Černý and Ercit (1985), and the magmatic and hydrothermal trends are from Marcoux et al., (2021). (c) Fe versus Ti versus Mn diagram (ppm) comparing the compositions of cassiterite from different pegmatites, based on LA-ICP-MS analyses. Cassiterite compositional trends for petalite- and Li-mica-rich pegmatites in possible relation with the vertical distance of migration of their parent magma are shown as arrows.