Knickpoints and crescentic bedform interactions in submarine channels
Chen, Ye; Parsons, Daniel R.; Simmons, Stephen M.; Williams, Rebecca; Cartigny, Matthieu J. B.; Hughes Clarke, John E.; Stacey, Cooper D.; Hage, Sophie; Talling, Peter J.; Azpiroz‐Zabala, Maria; Clare, Michael A.; Hizzett, Jamie L.; Heijnen, Maarten S.; Hunt, James E.; Lintern, D. Gwyn; Sumner, Esther J.; Vellinga, Age J.; Vendettuoli, Daniela
Professor Daniel Parsons D.Parsons@hull.ac.uk
Professor in Sedimentology/ Director, Energy and Environment Institute
Dr Steve Simmons S.Simmons@hull.ac.uk
Dr Rebecca Williams Rebecca.Williams@hull.ac.uk
Senior Lecturer; Associate Dean for Student Experience
Matthieu J. B. Cartigny
John E. Hughes Clarke
Cooper D. Stacey
Peter J. Talling
Michael A. Clare
Jamie L. Hizzett
Maarten S. Heijnen
James E. Hunt
D. Gwyn Lintern
Esther J. Sumner
Age J. Vellinga
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 important role in channel evolution and the behaviour of the submarine sediment-laden flows (turbidity currents) that traverse them. Although prior research has linked supercritical turbidity currents to the formation of both knickpoints and smaller crescentic bedforms, the relationship between flows and the dynamics of these seafloor features remains poorly constrained at field-scale. This study investigates the distribution, variation and interaction of knickpoints and crescentic bedforms along the 44km long submarine channel system in Bute Inlet, British Columbia. Wavelet analyses on a series of repeated bathymetric surveys reveal that the floor of the submarine channel is composed of a series of knickpoints that have superimposed, higher-frequency, crescentic bedforms. Individual knickpoints are separated by hundreds to thousands of metres, with the smaller superimposed crescentic bedforms varying in wavelengths from ca 16m to ca 128m through the channel system. Knickpoint migration is driven by the passage of frequent turbidity currents, and acts to redistribute and reorganize the crescentic bedforms. Direct measurements of turbidity currents indicate the seafloor reorganization caused by knickpoint migration can modify the flow field and, in turn, control the location and morphometry of crescentic bedforms. A transect of sediment cores obtained across one of the knickpoints show sand–mud laminations of deposits with higher aggradation rates in regions just downstream of the knickpoint. The interactions between flows, knickpoints and bedforms that are documented here are important because they likely dominate the character of preserved submarine channel-bed deposits.
Cartigny, M. J., Azpiroz-Zabala, M., Chen, Y., Parsons, D. R., Simmons, S. M., Williams, R., …Vendettuoli, D. (2021). Knickpoints and crescentic bedform interactions in submarine channels. Sedimentology, 68(4), 1358-1377. https://doi.org/10.1111/sed.12886
|Journal Article Type||Article|
|Acceptance Date||Apr 15, 2021|
|Online Publication Date||Apr 27, 2021|
|Deposit Date||May 25, 2021|
|Publicly Available Date||Apr 28, 2022|
|Peer Reviewed||Peer Reviewed|
|Keywords||Crescentic bedforms; Knickpoints; Sedimentary records; Submarine channels; Turbidity currents|
This file is under embargo until Apr 28, 2022 due to copyright reasons.
Contact Rebecca.Williams@hull.ac.uk to request a copy for personal use.
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