Cookies

We use cookies to ensure that we give you the best experience on our website. By continuing to browse this repository, you give consent for essential cookies to be used. You can read more about our Privacy and Cookie Policy.


Durham Research Online
You are in:

How to recognize crescentic bedforms formed by supercritical turbidity currents in the geologic record : insights from active submarine channels.

Hage, S. and Cartigny, M.J.B. and Clare, M.A. and Sumner, E.J. and Vendettuoli, D. and Hughes Clarke, J.E. and Hubbard, S.M. and Talling, P.J. and Lintern, D.G. and Stacey, C.D. and Englert, R.G. and Vardy, M.E. and Hunt, J.E. and Yokokawa, M. and Parsons, D.R. and Hizzett, J.L. and Azpiroz-Zabala, M. and Vellinga, A.J. (2018) 'How to recognize crescentic bedforms formed by supercritical turbidity currents in the geologic record : insights from active submarine channels.', Geology., 46 (6). pp. 563-566.

Abstract

Submarine channels have been important throughout geologic time for feeding globally significant volumes of sediment from land to the deep sea. Modern observations show that submarine channels can be sculpted by supercritical turbidity currents (seafloor sediment flows) that can generate upstream-migrating bedforms with a crescentic planform. In order to accurately interpret supercritical flows and depositional environments in the geologic record, it is important to be able to recognize the depositional signature of crescentic bedforms. Field geologists commonly link scour fills containing massive sands to crescentic bedforms, whereas models of turbidity currents produce deposits dominated by back-stepping beds. Here we reconcile this apparent contradiction by presenting the most detailed study yet that combines direct flow observations, time-lapse seabed mapping, and sediment cores, thus providing the link from flow process to depositional product. These data were collected within the proximal part of a submarine channel on the Squamish Delta, Canada. We demonstrate that bedform migration initially produces back-stepping beds of sand. However, these back-stepping beds are partially eroded by further bedform migration during subsequent flows, resulting in scour fills containing massive sand. As a result, our observations better match the depositional architecture of upstream-migrating bedforms produced by fluvial models, despite the fact that they formed beneath turbidity currents.

Item Type:Article
Full text:(VoR) Version of Record
Available under License - Creative Commons Attribution.
Download PDF (Advance online version)
(900Kb)
Full text:(VoR) Version of Record
Available under License - Creative Commons Attribution.
Download PDF (Final published version)
(925Kb)
Status:Peer-reviewed
Publisher Web site:https://doi.org/10.1130/g40095.1
Publisher statement:© 2018 The Authors Gold Open Access: This paper is published under the terms of the CC-BY license
Date accepted:17 April 2018
Date deposited:30 April 2018
Date of first online publication:26 April 2018
Date first made open access:No date available

Save or Share this output

Export:
Export
Look up in GoogleScholar