Queen Maud block: A newly recognized Paleoproterozoic (2.4–2.5 Ga) terrane in northwest Laurentia

The Queen Maud block of Arctic Canada is central to understanding the Proterozoic tectonic history of northwestern Laurentia, but its crustal history is largely unknown. Results of an in situ U-Pb zircon, monazite, and whole-rock Sm-Nd study through the central and eastern Queen Maud block indicate: (1) widespread 2.46–2.50 Ga magmatism derived from Neoarchean source rocks, (2) an extensive NE-trending 2.44–2.39 Ga sedimentary belt characterized by 2.45–2.50 Ga detritus, and (3) regional ca. 2.39 Ga granulite metamorphism. There is no evidence of metamorphic or magmatic activity at 1.9–2.0 Ga, concurrent with orogenesis in the adjacent Taltson-Thelon belt. We propose that the eastern Queen Maud block was the site of an incipient continental rift ca. 2.5 Ga. Exhumation of 2.46–2.50 Ga granitoids produced in the early stages of rifting provided detritus to a short-lived basin that underwent granulite metamorphism ca. 2.39 Ga.