Development of cutoff-related knickpoints during early evolution of submarine channels

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1130/G38397.1.

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Authors

Zoltan Sylvester , Jacob Covault

Abstract

Submarine channels are often thought of as having relatively simple geometries, with significant along-channel morphologic and stratigraphic continuity. Using high-resolution seismic reflection data from offshore Angola and a kinematic model of channel evolution, we present evidence that channels on the seafloor can develop slope variability as a result of meander cutoff events. When cutoffs develop, the shortened flow paths produce locally steep gradients, thus initiating knickpoints. Waves of knickpoint retreat and the related channel incision explain the occurrence of terraces and associated remnant channel deposits above the youngest channel thalweg. The simple processes of meander cutoff followed by knickpoint retreat are intrinsic to submarine channels and result in significant morphologic variability, erosion, and stratigraphic complexity, without any external forcing. These insights highlight the early evolution of submarine channels, a phase with a record that is commonly fragmented or completely absent as a result of subsequent erosion, and allow a better understanding of the autogenic controls on deep-marine stratigraphy.

DOI

https://doi.org/10.31223/osf.io/gxh3f

Subjects

Earth Sciences, Geology, Geomorphology, Physical Sciences and Mathematics

Keywords

stratigraphic architecture, Submarine channels, meandering, cutoffs, incision, sinuosity

Dates

Published: 2017-10-31 11:14

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License

Academic Free License (AFL) 3.0

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