Knickpoints and crescentic bedform interactions in submarine channels

Submarine channels deliver globally important volumes of sediments, nutrients, contaminants and organic carbon into the deep sea. Knickpoints are significant topographic features found within numerous submarine channels, which most likely play an role in channel evolution behaviour sediment-laden flows (turbidity currents) that traverse them. Although prior research has linked supercritical turbidity currents to formation both knickpoints smaller crescentic bedforms, relationship between dynamics these seafloor remains poorly constrained at field-scale. This study investigates distribution, variation interaction bedforms along 44 km long system Bute Inlet, British Columbia. Wavelet analyses on a series repeated bathymetric surveys reveal floor is composed have superimposed, higher-frequency, bedforms. Individual separated by hundreds thousands metres, with superimposed varying wavelengths from ca 16 m 128 through system. Knickpoint migration driven passage frequent currents, acts redistribute reorganize Direct measurements indicate reorganization caused knickpoint can modify flow field and, turn, control location morphometry A transect sediment cores obtained across one show sand–mud laminations deposits higher aggradation rates regions just downstream knickpoint. The interactions flows, documented here because they dominate character preserved channel-bed deposits.