Linear-stability analysis of plane beds under flows with suspended loads

Plane beds develop under flows in fluvial and marine environments; they are recorded as parallel lamination in sandstone beds, such as those found in turbidites. However, whereas turbidites typically exhibit parallel lamination, they rarely feature dune-scale cross-lamination. Although the reason fo...

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Bibliographic Details
Published in:Earth surface dynamics 2023-10, Vol.11 (5), p.961-977
Main Authors: Ohata, Koji, Naruse, Hajime, Izumi, Norihiro
Format: Article
Language:English
Subjects:
Analysis
Bed load
Channel flow
Cross laminating
Dunes
Flow control
Flow velocity
Geomorphology
Laminated materials
Lamination
Loads (forces)
Marine environment
Open channel flow
Reynolds number
Sandstone
Sediment transport
Sedimentary rocks
Stability analysis
Suspended load
Theoretical analysis
Turbidites
Turbidity
Turbidity currents
Viscosity
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Summary:Plane beds develop under flows in fluvial and marine environments; they are recorded as parallel lamination in sandstone beds, such as those found in turbidites. However, whereas turbidites typically exhibit parallel lamination, they rarely feature dune-scale cross-lamination. Although the reason for the scarcity of dune-scale cross-lamination in turbidites is still debated, the formation of dunes may be dampened by suspended loads. Here, we perform, for the first time, linear-stability analysis to show that flows with suspended loads facilitate the formation of plane beds. For a fine-grained bed, a suspended load can promote the formation of plane beds and dampen the formation of dunes. These results of theoretical analysis were verified with observational data of plane beds under open-channel flows. Our theoretical analysis found that suspended loads promote the formation of plane beds, which suggests that the development of dunes under turbidity currents is suppressed by the presence of suspended loads.
ISSN:2196-632X
2196-6311
2196-632X
DOI:10.5194/esurf-11-961-2023