Evaluation of Morphodynamic Controls on the Preservation of Fluvial Meander‐Belt Deposits

Yan, Na; Colombera, Luca; Mountney, Nigel P.

doi:10.1029/2021gl094622

Cited by 5 publications

(3 citation statements)

References 36 publications

(65 reference statements)

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“…In this study, it was possible to track both topographic and sediment changes associated with fluvial meandering dynamics, that is, complementing works that mainly tracked topographic changes in physical experiments (Straub & Esposito, 2013; Straub & Foreman, 2018) or numerical simulations (e.g., Durkin et al., 2017; Wang et al., 2021; Yan et al., 2021). Results show that this combination of topographic and facies replacement measurement allows for a better prediction of completeness than topographic data alone (comparison between Figures 12a and 12d).…”

Section: Discussionmentioning

confidence: 91%

“…On the other hand, we chose to extract grid data every 200 iteration, which corresponds to ca. 300 years in nature, so that this study has a limited resolution on lower architectural hierarchies (accretion packages) compared to a recent study by Yan et al (2021). We do include a comparable degree of complexity at the scale of channel belt, since FLUMY also includes changes of direction of migration and bend cut-offs (Lemay, 2018).…”

Section: Limitations Of the Approachmentioning

confidence: 99%

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Preservation and Completeness of Fluvial Meandering Deposits Influenced by Channel Motions and Overbank Sedimentation

et al. 2022

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Assessing the contribution of geomorphic processes to the (non‐)preservation of sedimentary deposits is necessary to account for potential bias in measured accumulation rates in the stratigraphic record. In this study, a series of numerical simulations of fluvial meandering successions is performed using FLUMY, a model of channel motions and sedimentary facies deposition. We develop tools to measure non‐deposition (stasis S) and reworking (R) of previously deposited sediment between iterations, which are both generators of hiatuses in the sedimentary record. We then compare S and R with measurements of accumulation rates and completeness (C). Results show that combining measurements of both topographic and facies changes allows for a better record of surface evolution than measuring topographies only. Accumulation rate dependence on measurement time span allows distinguishing between two regimes. The first one (anti‐persistent) is characteristic of channel avulsion and compensational stacking until the whole domain is visited by overbank deposition, corresponding to the visitation timescale Tv. In the second regime (persistent), reworking by channel migration is the remaining active process until the whole system has aggraded one channel depth, corresponding to the compensation timescale Tc. Based on these results, we propose a new simple formulation based on stasis and reworking to estimate average completeness.

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Section: Discussionmentioning

confidence: 91%

Section: Limitations Of the Approachmentioning

confidence: 99%

Preservation and Completeness of Fluvial Meandering Deposits Influenced by Channel Motions and Overbank Sedimentation

et al. 2022

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“…However, empirical relationships between river and channel-belt planform patterns remain elusive. Previous work on channel belts has often studied single-channel and multichannel rivers separately (Limaye, 2020;Yan et al, 2021), while in nature, planform channel pat-terns are unlikely to conform to this binary classification (Galeazzi et al, 2021). Furthermore, while morphodynamic models have the capacity to allow rivers to self-form channel patterns, computation costs prevent these models from simulating deposits over geologic timescales (Nicholas, 2013).…”

Section: Introductionmentioning

confidence: 99%

Supplemental Material: Quantitative relationships between river and channel-belt planform patterns

Dong¹,

Goudge²

2022

Preprint

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Quantitative relationships between river and channel-belt planform patterns

Dong

Goudge

2022

Geology

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Channel planform patterns arise from internal dynamics of sediment transport and fluid flow in rivers and are affected by external controls such as valley confinement. Understanding whether these channel patterns are preserved in the rock record has critical implications for our ability to constrain past environmental conditions. Rivers are preserved as channel belts, which are one of the most ubiquitous and accessible parts of the sedimentary record, yet the relationship between river and channel-belt planform patterns remains unquantified. We analyzed planform patterns of rivers and channel belts from 30 systems globally. Channel patterns were classified using a graph theory-based metric, the Entropic Braided Index (eBI), which quantifies the number of river channels by considering the partitioning of water and sediment discharge. We find that, after normalizing by river size, channel-belt width and wavelength, amplitude, and curvature of the belt edges decrease with increasing river channel number (eBI). Active flow in single-channel rivers occupies as little as 1% of the channel belt, while in multichannel rivers it can occupy >50% of the channel belt. Moreover, we find that channel patterns lie along a continuum of channel numbers. Our findings have implications for studies on river and floodplain interaction, storage timescales of floodplain sediment, and paleoenvironmental reconstruction.

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Evaluation of Morphodynamic Controls on the Preservation of Fluvial Meander‐Belt Deposits

Cited by 5 publications

References 36 publications

Preservation and Completeness of Fluvial Meandering Deposits Influenced by Channel Motions and Overbank Sedimentation

Preservation and Completeness of Fluvial Meandering Deposits Influenced by Channel Motions and Overbank Sedimentation

Supplemental Material: Quantitative relationships between river and channel-belt planform patterns

Quantitative relationships between river and channel-belt planform patterns

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