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How do turbidity flows interact with contour currents in unidirectionally migrating deep-water channels?

Gong Chenglin, Wang Yingmin, Michele Rebesco, Stefano Salon and Ronald J. Steel
How do turbidity flows interact with contour currents in unidirectionally migrating deep-water channels?
Geology (Boulder) (April 2018) 46 (6): 551-554

Abstract

Inspired by the two-layer model of a stratified lake forced by wind stress, we introduce the concept of Wedderburn number (W) to quantify, for the first time, how turbidity and contour currents interacted to determine sedimentation in unidirectionally migrating deep-water channels (UCs). Bankfull turbidity flows in the studied UCs were computed to be supercritical (Froude number of 1.11-1.38) and had velocities of 1.72-2.59 m/s. Contour currents with assumed constant velocities of between 0.10 m/s and 0.30 m/s flowing through their upper parts would result in pycnoclines between turbidity and contour currents, with amplitudes of up to 7.07 m. Such pycnoclines, in most cases, would produce Kelvin-Helmholtz billows and bores that had velocities of 0.87-1.48 m/s and prograded toward the steep channel flanks by 4.0 degrees to 19.2 degrees . Pycnoclines' wavefronts with the strongest shocks and deepest oscillations would, therefore, occur preferentially along the steep flanks, thereby promoting erosion; on the other hand, their wavetails with the weakest shocks and shallowest oscillations would occur preferentially along the gentle flanks, thereby promoting deposition. Such asymmetric intra-channel deposition, in turn, forced individual channels to consistently migrate toward the steep flanks, forming channels with unidirectional channel trajectories and asymmetrical channel cross sections.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 46
Serial Issue: 6
Title: How do turbidity flows interact with contour currents in unidirectionally migrating deep-water channels?
Affiliation: China University of Petroleum, State Key Laboratory of Petroleum Resources and Prospecting, Beijing, China
Pages: 551-554
Published: 20180426
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 11
Accession Number: 2018-055885
Categories: OceanographyApplied geophysics
Document Type: Serial
Bibliographic Level: Analytic
Annotation: GSA Data Repository item 2018180
Illustration Description: illus. incl. sects., sketch map
Secondary Affiliation: Istituto Nazionale di Oceanografia e di Geofisica Sperimentale, ITA, ItalyUniversity of Texas at Austin, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201830
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