DETRITAL ZIRCON AGE SPECTRA FROM PROTEROZOIC TO CARBONIFEROUS CLASTIC STRATA OF THE PEARYA TERRANE, CANADIAN ARCTIC ISLANDS (Invited Presentation)

The Pearya Terrane, on the northernmost margin of Ellesmere Island, preserves a sedimentary record of Proterozoic to Paleozoic sedimentary rocks. Detrital zircon datasets from critical time intervals provide tests for Paleozoic reconstructions of the Laurentian Arctic margin. The sedimentary rocks record the origin of the Pearya terrane in the North Atlantic Caledonides, Silurian accretion against the Franklinian Basin, the Ellesmereian Orogeny, and subsidence of the Sverdrup Basin. Proterozoic sections, Succession II of Trettin (1987), are characterized by abundant Mesoproterozoic to late Paleoproterozoic age peaks consistent with a Grenvillian-Sveconorwegian provenance. Peaks at c. 970 Ma and minor c. 600 Ma - 700 Ma peaks occur in some samples. Late Ordovician arc sands are dominated by ages coeval with documented c. 450 Ma-470 Ma magmatism. Latest Ordovician to early Silurian sandstones record Proterozoic age peaks indicative of recycling of material from Succession II. Uncommon Cryogenian grains occur in some sandstone samples. Clastic units deposited after Silurian accretion record both recycled zircon as well as increased contributions from Paleoproterozoic to Archean sources that are diagnostic of the northern Laurentian margin. The late Devonian Okse Bay Fm. yields abundant Mesoproterozoic ages and increased Paleoproterozoic-Archean ages relative to older units. Prominent peaks from c. 400 Ma - c. 450 Ma likely represent Caledonide sources, and uncommon 520 Ma - 700 Ma ages suggest a Timanide or displaced fragment (e.g. Arctic Alaska) provenance. Carboniferous deposition in the northwest margin of the Sverdrup basin continues the recycling trend, with contributions from Paleoproterozoic to Archean sources increasing in abundance from the basal (Visean) Emma Fiord Fm. through Serpukhovian - Moscovian units. A basal conglomerate from the Bashkirian Canyon Fiord Fm. is dominated by reworked material from the Ordovician arc which it unconformably overlies. Detrital zircon spectra of the Pearya terrane provide a fingerprint for terranes derived from the North Atlantic Caledonides. Svalbard and Pearya preserve a signal for terranes that evolved at the northwest end of the orogen, linking Circum-Arctic terranes to their starting positions in Paleozoic reconstructions.