U-Pb and geochemical evidence for a Cryogenian magmatic arc in central Novaya Zemlya, Arctic Russia

P>A unique set of mafic intrusives collected during a 1921 expedition to Novaya Zemlya and reported to cut Devonian sedimentary rocks, are shown instead to represent a Cryogenian magmatic arc. Zircon and titanite in four samples from Mashigin Fjord and Matochkin Strait yield U-Pb ages of 716-704 Ma and the dyke geochemistry shows typical subduction-zone features. These rocks have the characteristics of a peri-Gondwanan subduction-related complex, and originally could have been affiliated to the Avalonian systems before accreting to Baltica during the Timanian orogeny.