DETRITAL ZIRCON GEOCHRONOLOGY OF NEOPROTEROZOIC AND PALEOZOIC UNITS OF THE PEARYA TERRANE, ELLESMERE ISLAND, CANADA

The Pearya terrane is a well documented exotic terrane in the Canadian Arctic Islands that is marked by Meso/Neoproterozoic age basement juxatposed against the Archean to Paleoproterozoic age basement of Northern Canada and Greenland. Much of the early tectonic history is enigmatic; however, the terrane preserves a stratigraphic record from the Neoproterozoic to Paleozoic that provides a record of the terrane’s evolution. Preliminary U/Pb analyses of detrital zircon separates from several intervals in the stratigraphic section reveal ages that help constrain source areas for sediment delivered to the Pearya terrane, as well as possible paleogeographic relationships amongst terranes originating in the Arctic realm. Ten samples selected to cover major stratigraphic intervals in the Neoproterozoic and Paleozoic section of the Pearya terrane have been analyzed at the University of Arizona LaserChron facility. Two quartzite samples from the Neoproterozoic Y2 unit show age peaks at 1880-1775 Ma, 1425-1500 Ma, 1270-1400 Ma, and 1000-1200 Ma. A sample from the Ordovician Taconite River Fm. yielded a complex pattern of ages, with peaks at 2725 Ma, several between 1320-1885 Ma, and at 965-1155 Ma, 770-800 Ma, 680 Ma, 605 Ma, and 505 Ma. Three Lower Silurian samples show age peaks at around 1800-1900 Ma, 1640 Ma, 1445 Ma, 1360 Ma, 1035-1120 Ma, and 965 Ma. A peak at about 630 Ma is observed in a sample from the Danish River Fm. The youngest peaks appear at 450 Ma, possibly reflecting a Caledonian source. Two Middle Devonian samples from the Okse Bay Fm. reveal peaks at 1980 Ma, 1825 Ma, 1640 Ma, 1470 Ma, 1340 Ma, 1050-1140 Ma, 960 Ma, 570-670 Ma, 430 Ma and 395 Ma. A Carboniferous pebble conglomerate unit gave a strong peak at 475 Ma that likely reflects a local source, and minor peaks of Paleoproterozoic and Archean ages. The observed detrital age spectra are consistent with correlation of the Pearya terrane with terranes of Svalbard and proximity of Pearya to the northern Caledonides, the Timanides, and other terranes possibly derived from the Arctic region including the Arctic Alaska-Chukotka microplate and Alexander terrane.