Ho, V.L., Dorrell, R.M., Keevil, G.M. et al. (2 more authors) (2018) Scaling analysis of multipulsed turbidity current evolution with application to turbidite interpretation. Journal of Geophysical Research: Oceans, 123 (5). pp. 3668-3684. ISSN 2169-9275
Abstract
Deposits of submarine turbidity currents, turbidites, commonly exhibit upward‐fining grain size profiles reflecting deposition under waning flow conditions. However, more complex grading patterns such as multiple cycles of inverse‐to‐normal grading are also seen and interpreted as recording deposition under cycles of waxing and waning flow. Such flows are termed multipulsed turbidity currents, and their deposits pulsed or multipulsed turbidites. Pulsing may arise at flow initiation, or following downstream flow combination. Prior work has shown that individual pulses within multipulsed flows are advected forward and merge, such that complex longitudinal velocity profiles eventually become monotonically varying, although transition length scales in natural settings could not be predicted. Here we detail the first high frequency spatial (vertical, streamwise) and temporal measurements of flow velocity and density distribution in multipulsed gravity current experiments. The data support both a process explanation of pulse merging and a phase‐space analysis of transition length scales; in prototype systems, the point of merging corresponds to the transition in any deposit from multipulsed to normally graded turbidites. The scaling analysis is limited to quasi‐horizontal natural settings in which multipulsed flows are generated by sequences of relatively short sediment failures (<10 km long) that develop progressively up‐dip and predicts pulse merging after only a few tens of kilometers. The model cannot provide quantitative estimation of merging in down‐slope flows generated by axially extensive (>10 km) sequences of breaches or where pulsing arises from combination at confluences of single‐pulsed flows, such flows may be responsible for the pulsing signatures seen in some distal turbidites, >100 km from source.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2018 American Geophysical Union. This is an author-produced version of a paper subsequently published in Journal of Geophysical Research: Oceans. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | turbidity currents; turbidites; pulsed turbidites |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Civil and Structural Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 23 Aug 2019 10:36 |
Last Modified: | 23 Aug 2019 10:36 |
Status: | Published |
Publisher: | American Geophysical Union (AGU) |
Refereed: | Yes |
Identification Number: | 10.1029/2017jc013463 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:150063 |