Petrography, geochemistry, and petrogenesis of Li-enriched and Li-poor aplite–pegmatites in the Preissac–Lacorne area, Abitibi subprovince, Canada

• Both types of aplite–pegmatites are peraluminous, calc-alkaline intrusions with syenitic to granitic compositions. • Spodumene is the main lithium mineral and occurs in three generations: magmatic, magmatic-hydrothermal, and hydrothermal. • They are late- to post-tectonic intrusions derived from residual S-type magmas and from shear zone-controlled crustal anatexis along the MFS. The Preissac–Lacorne area, within the Archean Abitibi granite–greenstone belt, hosts numerous Li-enriched and Li-poor aplite–pegmatites. Both suites are strongly peraluminous, calc-alkaline, late- to post-tectonic composite intrusions cutting through the monzogranite–granodiorite suite and associated volcano-sedimentary sequences along the Manneville Fault System (MFS). The Li-enriched aplite–pegmatites, products of at least two distinct mineralizing events, are more highly differentiated (K/Rb = 18) than their Li-poor counterparts (K/Rb = 26) and contain three generations of spodumene formed through magmatic to magmatic–hydrothermal processes. Both suites likely represent multiple generations of aplite–pegmatites, including those derived from the S-type Lamotte monzogranite and those formed by shear zone-controlled anatexis along the MFS. Field observations indicate that shear-related partial melting of metasedimentary and granodioritic rocks generated Li-poor aplite–pegmatites, whereas partial melting of the monzogranite under similar conditions produced Li-enriched varieties. Overall, both suites appear genetically linked to episodic activation of the MFS prior to and during the waning stages of regional deformation.