The Seafloor of Southeastern Canada

Quaternary glaciations played a critical role in producing the modern landscape of the seafloor of southeastern Canada. Glacial landscapes such as cross-shelf troughs, fjords, recessional moraines and tunnel valleys were sculpted by the Laurentide Ice Sheet. Following deglaciation, relative sea level rise led to the formation of sandy bedforms and tidal scours on the continental shelf. In contrast, the deep-water margin was not directly modified by the ice sheet, but was significantly influenced by it. Large quantities of glacigenic sediments were distributed along the continental slope during the last glacial maximum through turbidity currents, contour currents and submarine landslides. Turbidity currents eroded submarine canyons and deposited submarine fans, which are among the largest sediment accumulations in southeastern Canada. Although the continental shelf and the deep-water margin have contrasting landscapes, they are genetically linked to tectonics and the pattern of retreat of the Laurentide Ice Sheet. This chapter gives an overview of the landscape and landforms of the seafloor of southeastern Canada and details how its glacial heritage played a major role in sculpting the modern seabed.