Granulite facies ortho- and paragneisses and felsic intrusive rocks form the crystalline core of the Boothia Uplift, which extends northward from Boothia Peninsula into the Arctic Archipelago. The rocks dated come from northern Boothia Peninsula, western Somerset Island, and eastern Prince of Wales Island, between 71 °N and 74°N. Zircon ages of protoliths of orthogneissic rocks range from 2.48 to ca. 2.2 Ga. A major thermal event, involving syenitic magmatism and high-grade metamorphism, occurred in the interval 1.94-1.92 Ga; magmatism may have preceded metamorphism by 1 0 or 20 Ma. A massive, porphyritic rapakivi granite in northern Somerset Island intruded 1 .71 Ga ago. Metamorphic and intrusive ages in the 1.9-2.0 Ga range in the Boothia Uplift are similar to those in the Thelon Tectonic Zone on the mainland to the southwest. Compared with the Thelon zone, however, crystallization ages of gneissic protoliths are, in general, older and the nature of the intrusive suite is significantly different in the Boothia Uplift.