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A new modelling approach to sediment bypass prediction applied to the East Coast Basin, New Zealand

Crisóstomo-Figueroa, Adriana; McArthur, Adam D.; Dorrell, Robert M.; Amy, Lawrence; McCaffrey, William D.

Authors

Adriana Crisóstomo-Figueroa

Adam D. McArthur

Lawrence Amy

William D. McCaffrey



Abstract

Predicting when turbidity currents are erosional or depositional (i.e., leaving no depositional record versus leaving a deposit) remains challenging. Here we combine observations from submarine channel morphology with a new sediment transport model to derive thresholds for net erosional, equilibrium, or net depositional flow to predict how far turbidity currents can transport different grain size classes down the channel. The approach was applied to the modern Madden and Omakere Channels, which traverse the Hikurangi subduction margin of the North Island of New Zealand. A bathymetric data set was used to establish the downstream change of channel geometry. Taking account of centripetal and Coriolis forces, the flow superelevation method was used to estimate variations in flow velocity and concentration along the channels. These parameters were used as model inputs to estimate the potential distribution of sand in the system assuming the separate cases of well-sorted and poorly-sorted sediment in suspension. The predicted sand distribution maps deposited by poorly-sorted flows in the channels show good agreement with root mean square amplitude mapping of the seafloor. These results confirm that thicker flows, and those carrying well-sorted suspensions, can bypass sediment over lower slopes than thinner flows and those carrying more poorly-sorted suspensions. The net erosion and net deposition thresholds derived from this study may help to guide and constrain predictions of potential sediment bypass zones in seafloor and subsurface systems and hence better constrain the predicted loci of deposition.

Citation

Crisóstomo-Figueroa, A., McArthur, A. D., Dorrell, R. M., Amy, L., & McCaffrey, W. D. (2021). A new modelling approach to sediment bypass prediction applied to the East Coast Basin, New Zealand. Geological Society of America Bulletin, 133(7-8), 1734-1748. https://doi.org/10.1130/B35687.1

Journal Article Type Article
Acceptance Date Sep 23, 2020
Online Publication Date Dec 16, 2020
Publication Date Jul 1, 2021
Deposit Date Nov 6, 2020
Publicly Available Date Mar 28, 2024
Journal Bulletin of the Geological Society of America
Print ISSN 0016-7606
Electronic ISSN 1943-2674
Publisher Geological Society of America
Peer Reviewed Peer Reviewed
Volume 133
Issue 7-8
Pages 1734-1748
DOI https://doi.org/10.1130/B35687.1
Keywords Australasia; Bathymetry; Channels; Clastic sediments; Currents; Deposition; East Coast Basin; Equilibrium; Erosion; Geometry; Grain size; Hikurangi Margin; Marine environment; New Zealand; North Island; Ocean floors; Prediction; Sand; Sediment transport;
Public URL https://hull-repository.worktribe.com/output/3654929
Publisher URL https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/doi/10.1130/B35687.1/593338/A-new-modelling-approach-to-sediment-bypass?redirectedFrom=fulltext

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Copyright Statement
©2020 The authors. All rights reserved. No part of this publication may be reproduced without the written permission of the copyright holder





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