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The critical role of stratification in submarine channels: Implications for channelization and long runout of flows

Dorrell, R. M.; Darby, S. E.; Peakall, J.; Sumner, E. J.; Parsons, D. R.; Wynn, R. B.

Authors

S. E. Darby

J. Peakall

E. J. Sumner

R. B. Wynn

Abstract

Channelized submarine gravity currents travel remarkable distances, transporting sediment to the distal reaches of submarine fans. However, the mechanisms by which flows can be sustained over these distances remain enigmatic. In this paper we consider two shallow water models the first assumes the flow is unstratified whilst the second uses empirical models to describe vertical stratification, which effects depth averaged mass and momentum transfer. The importance of stratification is elucidated through comparison of modeled flow dynamics. It is found that the vertically stratified model shows the best fit to field data from a channelized field-scale gravity current in the Black Sea. Moreover, the stratified flow is confined by the channel to a much greater degree than the flow in the unstratified model. However, both models fail to accurately represent flow dynamics in the distal end of the system, suggesting current empirical stratification models require improvement to accurately describe field-scale gravity currents. It also highlights the limitations of weakly stratified small-scale experiments in describing field-scale processes. The results suggest that in real-world systems stratification is likely to enable maintenance of velocity and discharge within the channel, thus facilitating sediment suspension over distances of hundreds of kilometers on low seafloor gradients. This explains how flows can travel remarkable distances and transport their sediment to the distal parts of submarine fans.

Journal Article Type Article
Publication Date 2014-04
Journal Journal of geophysical research : oceans
Print ISSN 2169-9275
Electronic ISSN 2169-9291
Publisher American Geophysical Union
Peer Reviewed Peer Reviewed
Volume 119
Issue 4
Pages 2620-2641
DOI https://doi.org/10.1002/2014jc009807
Keywords Stratification, Density-driven flow
Publisher URL http://onlinelibrary.wiley.com/doi/10.1002/2014JC009807/abstract;jsessionid=568AD01DF57BDD220C5A1FADF75DF9F2.f03t03
Additional Information This is a copy of an open access article published in: Journal of geophysical research : oceans, 2014, v.119 issue 4.

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