An overview of the geology and tectonic evolution of the Labrador‒Baffin Seaway and adjacent onshore regions

The Labrador Sea, Davis Strait, and Baffin Bay offshore regions, collectively referred to as the Labrador–Baffin Seaway, and adjacent onshore areas including Baffin Island, Bylot Island, and West Greenland, comprise the northeastern Canadian and Western Greenland Arctic margins. The rocks of these areas preserve a long and complex geological history that records numerous tectonic events. This history is synthesized in a Geological Survey of Canada Bulletin, the result of significant collaboration between several governments and academic institutions. The geological evolution of the region begins with the assembly of a number of distinct Archean cratons in the early Paleoproterozoic, which resulted in the formation of the eastern Laurentian portion of the supercontinent Nuna (Columbia). Subsequent localized extension during supercontinent breakup in the Mesoproterozoic formed the Bylot basins exposed on northern Baffin Island and beneath northern Baffin Bay, as well as in surrounding onshore areas. During the early Paleozoic, sedimentary platform successions accumulated following the breakup of the supercontinent Rodinia. Deposition of these successions ceased with the closing of Paleozoic seaways and the formation of the supercontinent Pangea. Pangea underwent extension in the Labrador–Baffin Seaway region starting in the Early Cretaceous, resulting in the eventual separation of Greenland from the paleo-North American plate. Cretaceous rift phases were followed by oceanic crust formation and related tectonism starting in the Maastrichtian in the Labrador Sea and developing northward in the Paleocene before seafloor spreading ended in the late Paleogene. This tectonism led to the formation of several Mesozoic–Cenozoic sedimentary basins in the Labrador–Baffin Seaway and locally along onshore parts of the margin. The unique geology of the region has resulted in a seismically active area that contains significant mineral (iron, diamonds, zinc, lead, nickel, copper, platinum-group elements, uranium, thorium, gemstones, carving stone, and coal) and hydrocarbon (onshore and offshore) potential. Detailed papers in this Bulletin will serve as important source material for future work in this part of the Arctic.