CHARACTERIZING THE SEDIMENTARY PROVENANCE OF PRE-MISSISSIPPIAN STRATIGRAPHY ON THE NORTH SLOPE SUBTERRANE OF ARCTIC ALASKA

The Arctic Alaska terrane is critical for reconstructing the Paleozoic and Mesozoic tectonic evolution of the Arctic. The North Slope subterrane of Arctic Alaska extends from the Brooks Range of Alaska into the British and Barn Mountains of adjacent Yukon, Canada. The oldest rocks exposed on the North Slope subterrane consist of a late Neoproterozoic to early Paleozoic carbonate platform surrounded by poorly understood basinal siliciclastic and mafic volcanic rocks. A significant portion of these siliciclastic strata are grouped into the broadly defined Neruokpuk Formation and Road River Group, which have been correlated with units exposed in northwestern Laurentia. Here, we present sedimentary provenance data, including Nd isotope geochemistry, bulk major and trace element geochemistry, and thin section point counting on samples of shale, phyllite, and sandstone collected from these map units with the goal of providing detailed characterization and regional correlation of the pre-Mississippian stratigraphy of the North Slope. When combined with paleontological and geochronological age constraints on these strata, these data demonstrate multiple distinct and identifiable provenance signatures, indicating discrete shifts in sediment sources during latest Neoproterozoic–Devonian basin evolution. These data can also be compared to previous sedimentary provenance studies along Laurentia’s margins, as well as new data from the Yukon stable block, and test previous correlations with Neoproterozoic and Paleozoic strata in northwestern Laurentia. Although precise age constraints are lacking, the broad timing of the shift in the provenance of siliciclastic strata on the North Slope subterrane of Arctic Alaska is consistent with tectonic and paleogeographic links to the Caledonian and Ellesmerian orogenies of northeastern Laurentia.