Pre‐Vegetation, Single‐Thread Rivers Sustained by Cohesive, Fine‐Grained Bank Sediments: Mesoproterozoic Stoer Group, NW Scotland
نویسندگان
چکیده
A Silurian shift in fluvial stratigraphic architecture, coincident with the appearance of terrestrial vegetation fossil record, is traditionally cited as evidence for exclusively shallow, braided planforms pre-vegetation rivers. While recent recognition deep, single-thread channels pre-Silurian strata challenge this paradigm, it unclear how these rivers maintained stable banks. Here, we reconstruct paleohydraulics and channel planform from cross-strata 1.2 Ga Stoer Group. These deposits are consistent deep (4–7 m), low-sloping (2.7 × 10−4 to 4.5 10−5), similar morphometry modern We show that reconstructed bank shear stresses approximate cohesion provided by sand-mud mixtures 30%–45% mud—consistent floodplain facies composition. results indicate sediment mud alone could have fostered single-thread, suggest mark a kinematic change migration rate rather than diversification planform.
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ژورنال
عنوان ژورنال: Geophysical Research Letters
سال: 2023
ISSN: ['1944-8007', '0094-8276']
DOI: https://doi.org/10.1029/2023gl104379