Geologic characterization of Northeast Atlantic Submarine Canyons and Seamounts using observations from the NOAA Deep Connections 2019 Expedition
Seafloor mapping conducted during leg 1 of Deep Connections 2019 show ample evidence of recent geologic activity within submarine canyons, including axial channel incision, high reflectivity/rugosity “fresh” debris fields downslope of canyon walls, and occasionally sediment ripples. A small subset of the general area of interest has been surveyed by NOAA three times using high resolution multibeam: prior to 2009, 2013, and 2019. The difference in depth between these surveys identify recent slope failures and potential post-failure modification of large landslide scars. ROV dives during Deep Connections 2019 provided ground truth evidence of recent geological activity, including slope-parallel erosional rills down canyon walls, talus and debris fields without sediment drape, and gravel-laden canyon floors. These observations corroborate previous recent findings indicating submarine canyons host widespread albeit small scale geological activity during sea level highstands.