Zircon geochronology and geochemistry of the Ward Hunt pluton, Pearya terrane, Canadian High Arctic: Insights into its age, origin, and circum-Arctic Timanide connections

Abstract

The northern margin of the Neoproterozoic Timanide Orogen is truncated by Paleozoic deformation of the Caledonian Orogen. Evidence for dispersion of terranes affected by the Timanide Orogen is documented through contemporaneous tectonothermal activity, and by detrital zircon in sedimentary rock from across the Arctic Ocean margins. However, directly tying these terranes to the Caledonide realm is hindered by the paucity of appropriate events in proximal terranes. The Ward Hunt Pluton, a previously undated syenite–monzodiorite intrusion located on Ward Hunt Island, northern Pearya terrane, yields a crystallization age of 542 ± 2 Ma. Trace-element data from the igneous zircon suggest that the pluton intruded older metasedimentary rocks of the terrane as part of a volcanic arc system, indicated by juvenile Hf isotopic signatures and trace-element data. The data support links between the Pearya terrane and other Neoproterozoic–Cambrian arc systems, such as those proposed in Arctic Alaska-Chukota and the Alexander terrane.