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Preservation of meandering river channels in uniformly aggrading channel belts

Citation

van de Lageweg, WI and Schuurman, F and Cohen, KM and van Dijk, WM and Shimizu, Y and Kleinhans, MG, Preservation of meandering river channels in uniformly aggrading channel belts, Sedimentology, 63, (3) pp. 586-608. ISSN 0037-0746 (2016) [Refereed Article]

Copyright Statement

© 2015 The Authors. Sedimentology © 2015 International Association of Sedimentologists.

DOI: doi:10.1111/sed.12229

Abstract

Channel belt deposits from meandering river systems commonly display an internal architecture of stacked depositional features with scoured basal contacts due to channel and bedform migration across a range of scales. Recognition and correct interpretation of these bounding surfaces is essential to reconstruction of palaeochannel dimensions and to flow modelling for hydrocarbon exploration. It is therefore crucial to understand the suite of processes that form and transfer these surfaces into the fluvial sedimentary record. Here, the numerical model ‘NAYS2D’ is used to simulate a highly sinuous meandering river with synthetic stratigraphic architectures that can be compared directly to the sedimentary record. Model results highlight the importance of spatial and temporal variations in channel depth and migration rate to the generation of channel and bar deposits. Addition of net uniform bed aggradation (due to excess sediment input) allows quantification of the preservation of meander morphology for a wide range of depositional conditions. The authors find that the effect of vertical variation in scouring due to channel migration is generally orders of magnitude larger than the effect of bed aggradation, which explains the limited impact bed aggradation has on preservation of meander morphology. Moreover, lateral differences in stratigraphy within the meander belt are much larger than the stratigraphic imprint of bed aggradation. Repeatedly produced alternations of point bar growth followed by cut-off result in a vertical trend in channel and scour feature stacking. Importantly, this vertical stacking trend differs laterally within the meander belt. In the centre of the meander belt, the high reworking intensity results in many bounding surfaces and disturbed deposits. Closer to the margins, reworking is infrequent and thick deposits with a limited number of bounding surfaces are preserved. These marginal areas therefore have the highest preservation potential for complete channel deposits and are thus best suited for palaeochannel reconstruction.

Item Details

Item Type:Refereed Article
Keywords:aggradation, meandering river, morphodynamic modelling, preservation, stratigraphy
Research Division:Earth Sciences
Research Group:Physical Geography and Environmental Geoscience
Research Field:Geomorphology and Regolith and Landscape Evolution
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:van de Lageweg, WI (Dr Wietse Van De Lageweg)
ID Code:117117
Year Published:2016
Web of Science® Times Cited:5
Deposited By:Geography and Spatial Science
Deposited On:2017-05-31
Last Modified:2017-10-13
Downloads:0

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