Evidence for Timanian-age basement rocks in North Greenland as documented through U-Pb zircon dating of igneous xenoliths from the Midtkap volcanic centers

Abstract

Igneous xenoliths have been identified within the Paleozoic Midtkap volcanic centers of North Greenland that cut through Cambrian-Ordovician deep water trough sedimentary rocks that were subsequently deformed during the south-verging Ellesmerian Orogeny. The xenoliths were characterized geochemically and their zircons dated through the U-Pb technique. This provided ages ranging from 628 to 570 Ma, for xenoliths with granitic and monzonitic compositions, the former apparently older than the latter. These ages, coupled with the geochemical signature compatible with an arc setting, provide evidence for the presence of Timanian like basement in North Greenland. The structural setting suggests that the dated xenoliths belong to an allochthonous unit emplaced during the Caledonian Orogeny and deformed during the Ellesmerian Orogeny. Furthermore, this data provides new evidence for a northwestern extension (through continuation and/or through dispersal) of the late Neoproterozoic Timanide belt, from its type locality, in the Timan-Pechora region in Russia, through Svalbard, into North Greenland, to the Pearya Terrane on Ellesmere Island.