The rare-element pegmatites of the Superior Province host critical metals (Li, Cs, Rb, Ta) essential for developing sustainable technologies. In the Separation Lake greenstone belt, Li-bearing pegmatites have been interpreted to have intruded in one event at ca. 2640 Ma and been pervasively overprinted by a ductile shear fabric, which recrystallized the ore. However, recent investigations suggested that these rocks intruded over a ca. 55 Ma period (ca. 2655 to 2601 Ma) and that the fabrics in the mineralized dykes are related to magmatic process during emplacement and crystallization, rather than recrystallization. In the current study, a variety of analytical methods such as electron backscattered diffraction, in situ U-Pb geochronology and micro-XRF scans are used to correlate the mechanisms and timing of pegmatite emplacement with the deformational history of the greenstone belt. New data show that S-type granitic magmatism in the greenstone belt had commenced by ca. 2690 Ma and that the fabrics in granitic rocks in the marginal zones of the greenstone belt are due to deformation and recrystallization. Localized ductile deformation at ca. 2432 Ma post-dated the period of pegmatite crystallization but did not deform quartz and plagioclase in the pegmatite wall zones, nor biotite in the metasomatic haloes associated with dyke emplacement. Micro-XRF scans and LA-ICPMS transects of the pegmatite wall zones show enrichments in Ca and 87Sr* at the country rock interface, indicating open system behaviour between the pegmatites and the country rocks during emplacement and at a time after emplacement, respectively. The results from this study indicate that the fabrics and geometries of the dykes are essentially products of magmatic processes, and that emplacement was facilitated by a fluidization mechanism, in which metasomatism coincident with emplacement and crystallisation facilitated localized deformation to be imparted on the country rocks upon intrusion.