Seafloor Sediments, Morphologic Features, and Geotechnical Properties of Harrison Bay in the Alaskan Beaufort Sea

Abstract

Sediments on Arctic continental shelves are impacted by sea ice and ice-related processes for up to 9 months per year. As a result, seabed morphology in cold regions can exhibit features such as ice scours which are absent on lower-latitude shelves. Previous literature has provided rich qualitative and some quantitative assessments of keel scours and strudel scours (i.e., feature density) in pan-Arctic settings. However, based on a recent multibeam survey along >600 km of tracklines in Harrison Bay, Alaska, Arctic shelves can exhibit a much greater diversity of interesting morphologic features. In this paper we present an atlas of seabed features and some geotechnical properties observed across a 60 × 90 km portion of the Alaskan Beaufort Shelf, with the goal of highlighting the great diversity of Arctic continental-shelf seabed morphologies. We applied a combined approach of modern geomorphologic and geotechnical analysis of Arctic seabed environments, including: (a) machine learning algorithms applied to keel scour data, in order to better describe densities, geometries, and orientations at different water depths; and (b) portable free-fall penetrometer measurements collected at high spatial densities, in order to better characterize the geotechnical seabed properties associated with keel scour. Together this information about Arctic shelf seabed morphologies and applications of emerging quantitative tools to Arctic settings provides an advance in our understanding of Arctic seascape from a geotechnical and textural perspective.