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What determines the downstream evolution of turbidity currents?

Heerema, Catharina J.; Talling, Peter J.; Cartigny, Matthieu J.; Paull, Charles K.; Bailey, Lewis; Simmons, Stephen M.; Parsons, Daniel R.; Clare, Michael A.; Gwiazda, Roberto; Lundsten, Eve; Anderson, Krystle; Maier, Katherine L.; Xu, Jingping P.; Sumner, Esther J.; Rosenberger, Kurt; Gales, Jenny; McGann, Mary; Carter, Lionel; Pope, Edward

Authors

Catharina J. Heerema

Peter J. Talling

Matthieu J. Cartigny

Charles K. Paull

Lewis Bailey

Michael A. Clare

Roberto Gwiazda

Eve Lundsten

Krystle Anderson

Katherine L. Maier

Jingping P. Xu

Esther J. Sumner

Kurt Rosenberger

Jenny Gales

Mary McGann

Lionel Carter

Edward Pope



Abstract

© 2019 Seabed sediment flows called turbidity currents form some of the largest sediment accumulations, deepest canyons and longest channel systems on Earth. Only rivers transport comparable sediment volumes over such large areas; but there are far fewer measurements from turbidity currents, ensuring they are much more poorly understood. Turbidity currents differ fundamentally from rivers, as turbidity currents are driven by the sediment that they suspend. Fast turbidity currents can pick up sediment, and self-accelerate (ignite); whilst slow flows deposit sediment and dissipate. Self-acceleration cannot continue indefinitely, and flows might reach a near-uniform state (autosuspension). Here we show how turbidity currents evolve using the first detailed measurements from multiple locations along their pathway, which come from Monterey Canyon offshore California. All flows initially ignite. Typically, initially-faster flows then achieve near-uniform velocities (autosuspension), whilst slower flows dissipate. Fractional increases in initial velocity favour much longer runout, and a new model explains this bifurcating behaviour. However, the only flow during less-stormy summer months is anomalous as it self-accelerated, which is perhaps due to erosion of surficial-mud layer mid-canyon. Turbidity current evolution is therefore highly sensitive to both initial velocities and seabed character.

Journal Article Type Article
Publication Date Feb 15, 2020
Journal Earth and Planetary Science Letters
Print ISSN 0012-821X
Electronic ISSN 0012-821X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 532
Article Number 116023
APA6 Citation Heerema, C. J., Talling, P. J., Cartigny, M. J., Paull, C. K., Bailey, L., Simmons, S. M., …Pope, E. (2020). What determines the downstream evolution of turbidity currents?. Earth and planetary science letters, 532, https://doi.org/10.1016/j.epsl.2019.116023
DOI https://doi.org/10.1016/j.epsl.2019.116023
Keywords turbidity current; submarine canyon; ignition; dissipation; autosuspension; flow behaviour

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Copyright Statement
©2020 The Authors. Published by Elsevier B.V.





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