Similar curvature-to-width ratios for channels and channel belts: Implications for paleo-hydraulics of fluvial ridges on Mars

Geology ◽  
2021 ◽  
Author(s):  
Alistair T. Hayden ◽  
Michael P. Lamb ◽  
Alexander J. Carney
Keyword(s):  
Coarse Grained ◽  
Scaling Relations ◽  
Radius Of Curvature ◽  
Finite Width ◽  
Lateral Migration ◽  
River Channels ◽  
Meandering Rivers ◽  
Channel Belt ◽  
Stacking Patterns ◽  
Geometric Consequence

The surface of Mars contains abundant sinuous ridges that appear similar to river channels in planform, but they stand as topographic highs. Ridges have similar curvature-to-width ratios as terrestrial meandering rivers, which has been used to support the hypothesis that ridges are inverted channels that directly reflect channel geometry. Anomalously wide ridges, in turn, have been interpreted as evidence for larger rivers on Mars compared to Earth. However, an alternate hypothesis is that ridges are exhumed channel-belt deposits—a larger zone of relatively coarse-grained deposits formed from channel lateral migration and aggradation. Here, we measured landform wavelength, radius of curvature, and width to compare terrestrial channels, terrestrial channel belts, and martian ridges. We found that all three landforms follow similar scaling relations, in which ratios of radius of curvature to width range from 1.7 to 7.3, and wavelength-to-width ratios range from 5.8 to 13. We interpret this similarity to be a geometric consequence of a sinuous curved line of finite width. Combined with observations of ridge-stacking patterns, our results suggest that wide ridges on Mars could indicate fluvial channel belts that formed over significant time rather than anomalously large rivers.

Upstream and downstream morphodynamic influence in simulated and real meandering rivers

2021 ◽  
Author(s):  
Hossein amini ◽  
Guido Zolezzi ◽  
Federico Monegaglia ◽  
Emanuele Olivetti ◽  
Marco Tubino
Keyword(s):  
Migration Rate ◽  
Machine Learning Techniques ◽  
Stochastic Gradient Descent ◽  
Support Vector ◽  
Lateral Migration ◽  
Remotely Sensed Data ◽  
Meandering Rivers ◽  
Meandering River ◽  
Migration Rates ◽  
Meander Migration

<p>This study investigates the dependency of meander lateral migration rates on the spatial distribution of channel centerline curvature in both synthetic and real meandering rivers. It employs Machine Learning techniques (hereafter ML) to relate observed local lateral meander migration rates with the local and the upstream/downstream values of the centerline curvature. To achieve this goal, it was primarily essential to identify the feasibility of using ML in the meandering river's morphodynamics. We then determined the ability of ML to predict the excess near bank velocity based a set of input data using different regression techniques (linear and polynomial, Stochastic Gradient Descent, Multi-Layer Perceptron, and Support Vector Machine). We then moved forward to study the upstream-downstream influence on local migration rate. Synthetic meandering river planforms, as obtained through the planform evolution model of Bogoni et al. (2017), which is based on Zolezzi and Seminara (2001) meander flow model, were used as test cases for the calibration and check of the different adopted ML algorithms. The calibrated algorithms were then applied to multi-temporal information on meander planform dynamics obtained through the PyRiS software (Monegaglia et al., 2018), to quantify to which extent the upstream and downstream distribution of meander centerline curvature affects the local meander migration rate in real rivers.</p><p>References </p><p>1- Zolezzi, G., & Seminara, G. (2001b). Downstream and upstream influence in river meandering. Part 1. General theory and application overdeepening. Journal of Fluid Mechanics, 438(September 2015), 183–211. https://doi.org/10.1017/S002211200100427X</p><p>2- Monegaglia, F., Zolezzi, G., Güneralp, I., Henshaw, A. J., & Tubino, M. (2018). Automated extraction of meandering river morphodynamics from multitemporal remotely sensed data. In Environmental Modelling & Software (Vol. 105, pp. 171–186). https://doi.org/10.1016/j.envsoft.2018.03.028</p><p>3- Bogoni, M., Putti, M., & Lanzoni, S. (2017). Modeling meander morphodynamics over self-formed heterogeneous floodplains. In Water Resources Research (Vol. 53, Issue 6, pp. 5137–5157). https://doi.org/10.1002/2017wr020726</p><p>4- Benozzo, D.,  Olivetti, E., Avesani, P. (2017). Supervised Estimation of Granger-Based Causality between Time series. In Frontiers in Neuroinformatics. </p><p>https://doi.org/10.3389/fninf.2017.00068 </p><p>5- Sharma A., Kiciman, E. (2020). DoWhy: An End-to-End library for Causal Inference. arXiv preprint arXiv:2011.04216. </p><p>https://arxiv.org/abs/2011.04216</p>

scholarly journals Architecture, process, and environmental diversity in a late Cretaceous slope channel system

2020 ◽  
Vol 90 (1) ◽  
pp. 1-26 ◽  
Author(s):  
Benjamin Kneller ◽  
Guilherme Bozetti ◽  
Richard Callow ◽  
Mason Dykstra ◽  
Larissa Hansen ◽  
...  
Keyword(s):  
Building Blocks ◽  
Heavy Minerals ◽  
Coarse Grained ◽  
Turbidity Currents ◽  
Axial Region ◽  
Sedimentary Process ◽  
Channel System ◽  
Environmental Diversity ◽  
Channel Belt ◽  
Slope Channel

ABSTRACT Arroyo San Fernando, on the Pacific coast of Baja California, Mexico, provides a superb view of the architecture of a Maastrichtian active margin slope channel system and the record of its evolution through a third-order sea-level cycle. The succession is organized into architectural building blocks (channel-complex sets) consisting of a channel belt with an axial region and a channel-belt margin of terraces and internal levees. The channel belt is confined by an external levee on one side and by an erosion surface into the slope on the other. Each channel-complex set can be subdivided into three stages of evolution: Stage I consists of highly amalgamated coarse-grained channel complexes, Stage II consists of gravelly meander belts with marginal and stratigraphically intervening thin-bedded turbidites, and Stage III consists of mudstones representing abandonment. This succession is associated with repeated and therefore predictable changes in architecture, facies distribution, inferred seafloor morphology, and sedimentary process. We describe variability in the sedimentology, ichnology, palynology, provenance, and inferred sedimentary processes between and within these architectural elements. Channel formation and fill are attributed to erosion, sediment transport, and deposition by turbidity currents and lesser debris flows. Ichnology indicates enhanced oxygenation and supply of organic material, substrate type, and turbidity within the channel belt; the axial region can be differentiated from the terraces by differing response to turbidity-current intensity. Levee environments show ichnological gradients away from the channel towards background slope. Palynology reflects confinement of the supply of terrigenous material to the channel belt, but is also indicative of stratification within the turbidity-currents, as is the distribution of heavy minerals. Provenance is from the extinct part of the continental-margin arc to the east, via high-gradient gravelly streams and across a steep shoreline, with direct supply of coastal material to deep water. Architectural hierarchy bears comparison with other slope channel systems, but in common with them the fill represents only a small fraction of the time that the system was active.

Determining lateral migration rates of meandering rivers using fallout radionuclides

Geomorphology ◽  
2010 ◽  
Vol 123 (3-4) ◽  
pp. 364-369 ◽  
Author(s):  
E. Black ◽  
C.E. Renshaw ◽  
F.J. Magilligan ◽  
J.M. Kaste ◽  
W.B. Dade ◽  
...  
Keyword(s):  
Lateral Migration ◽  
Meandering Rivers ◽  
Migration Rates ◽  
Fallout Radionuclides

Seismic Sedimentology Research on Sublacustrine Fan of the Oligocene Dongying Formation, Liaozhong Depression, Bohai Bay Basin, Northeast China

2013 ◽  
Vol 807-809 ◽  
pp. 2151-2154 ◽  
Author(s):  
Yan Yan Chang ◽  
Chang Song Lin ◽  
Xin Huai Zhou ◽  
Shi Qiang Xia
Keyword(s):  
Seismic Reflection ◽  
Gamma Ray ◽  
High Resistivity ◽  
Bohai Bay ◽  
Lateral Migration ◽  
Multi Stage ◽  
Seismic Reflection Profiles ◽  
Seismic Reflections ◽  
Stacking Patterns ◽  
Order Sequence

In Liaozhong Depression, five types of sublacustrine fans are developed in the relative lowstand systems tracts of the fourth-order sequence in Dongying Formation. In drilling cores, typical turbidites characteristics exist including bedding structures such as slump deformation structure, parallel bedding, grading laminations and multi-stage scoured basal surfaces. They also can be recognized in well logs with distinctive low gamma-ray and high-resistivity stacking patterns. Logging curves usually display serrated bell shape, cylinder shape and funnel shape respectively. On seismic reflection profiles, sublacustrine fan typically shows lateral downlap on its external geometry and continuous or discontinuous “vermicular” reflection characteristics in its inner seismic reflection texture. According to the calibration results of drilling data, continuous seismic reflection profiles are interpreted to be mud-rich deposits with cohesive, soft sediment-deformation. Discontinuous seismic reflections with lateral migration and apparent incised valleys are interpreted to be sand-rich deposits which probably host the most potential litho-stratigraphic traps.

Unsteady two-dimensional flows with free boundaries - II. The incompressible inviscid jet

1956 ◽  
Vol 235 (1202) ◽  
pp. 382-395
Keyword(s):  
General Theory ◽  
Finite Time ◽  
Free Space ◽  
Radius Of Curvature ◽  
Finite Width ◽  
Two Dimensional ◽  
Free Boundaries ◽  
Early Stages ◽  
Large Container ◽  
Realistic Shape

The paper considers the flow which results when a slit of finite width is suddenly opened in a large container and a jet of fluid issues into free space. The early stages of the motion are discussed by expanding in powers of time. It is suggested that the jet boundary may be M-shaped initially. The shape of the jet after large but finite time is calculated by the general theory of part I to have a kink at the nose. However, by expanding in powers of the distance across the jet, the true radius of curvature of the nose has been evaluated. A realistic shape of the jet is sketched in figure 3.

scholarly journals Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data

Geologos ◽  
2012 ◽  
Vol 18 (3) ◽  
pp. 135-161 ◽  
Author(s):  
Maria I. Waksmundzka
Keyword(s):  
Source Area ◽  
High Energy ◽  
Coarse Grained ◽  
Type I ◽  
Braided River ◽  
River Channels ◽  
Fine Grained ◽  
Braided Rivers ◽  
Base Level ◽  
Se Poland

Abstract Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high. During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.

scholarly journals Autogenic translation and counter point bar deposition in meandering rivers

2021 ◽  
Author(s):  
Z. Sylvester ◽  
P.R. Durkin ◽  
S.M. Hubbard ◽  
D. Mohrig
Keyword(s):  
Satellite Imagery ◽  
Riparian Vegetation ◽  
Kinematic Model ◽  
Time Lapse ◽  
Sediment Deposition ◽  
Lateral Migration ◽  
Meandering Rivers ◽  
Point Bar ◽  
Point Bars ◽  
Meander Bends

Although it has long been recognized that deposition along meandering rivers is not restricted to convex banks (i.e., point bars), the consensus is that sediment deposition on concave banks of channel bends mostly occurs when meander bends translate downstream because erosion-resistant barriers inhibit their lateral migration. Using a kinematic model of channel meandering and time lapse satellite imagery from the Mamoré River in Bolivia, we show that downstream translation and associated concave bank deposition are essential, autogenic parts of the meandering process, and resulting counter point bars are expected to be present whenever perturbations such as bend cutoffs and channel reoccupations create short bends with high curvatures. The implication is that zones of concave bank deposition with lower topography, finer-grained sediment, slack water, and riparian vegetation that differs from point bars are more common than previously considered.

scholarly journals Simulation of Defects, Flexibility and Rupture in Biopolymer Networks

2021 ◽  
Author(s):  
Matthew H. J. Bailey ◽  
Mark Wilson
Keyword(s):  
Collagen Iv ◽  
Coarse Grained ◽  
Finite Width ◽  
Coarse Grained Model ◽  
Over Time ◽  
Hexagonal Network

Networks of biopolymers occur often in nature, and are vulnerable to damage over time. In this work, a coarse grained model of collagen IV molecules is applied in a 2D hexagonal network and the mechanisms by which these networks can rupture are explored. The networks are stretched linearly in order to study their structural limits and mechanism of rupture over timescale of up to 100 microseconds. Metrics are developed to track the damage networks suffer over time, and qualitatively analyse ruptures that occur. Further simulations repeatedly stretch the networks sinusoidally to mimic the in vivo strains. Defects of increasing levels of complexity are introduced into an ordered network, and their effect on the rupturing behaviour of the biopolymer networks studied. The effect of introducing holes of varying size in the network, as well as strips of finite width to mimic surgical damage are studied. These demonstrate the importance of the flexibility of the networks to preventing damage.

Structure of coarse grained braided stream alluvium

1979 ◽  
Vol 70 (10-12) ◽  
pp. 181-221 ◽  
Author(s):  
B. J. Bluck
Keyword(s):  
Climatic Conditions ◽  
Coarse Grained ◽  
Lateral Migration ◽  
Fine Sediments ◽  
High Stage ◽  
Lateral Channel ◽  
Braided Stream ◽  
Wide Range ◽  
Braided Streams ◽  
Flow Stage

SynopsisGrain size characteristics of the sediment and the flow stage characteristics of the river are the two most important factors influencing sedimentation in the channel zone. Climate is important in its influence on floodplain (overbank) sediment.Supra-bar platform (upper) parts of mature bars from a wide range of climatic conditions consistently show a sequence in the development of contained sedimentary structures which is related to the flow stage. At high stage, in rivers where the bed materials are quite mobile, the bar form is not thought to be present: the form develops on the falling stage, and the bar is dissected on the lowest stage. The various bar forms have a related diagnostic structure which determined from the nature and distribution of the stratification types, and the manner of their deposition on the falling flow stage. The exposed (supra-platform) parts of lateral bars have a side and longitudinally filled inner channel which comprises fine sediment. Medial bars have converging cross-strata in sands which are overlain partly by gravels in an upward coarsening sequence.Lateral migration of the channel zone, brought about by the preferential bar accretions to one side, results in building of a lithosome, the facies structure of which is partly determined by the nature of the bar accretions. As the channel migrates the abandoned bars may be covered with fine sediments so as to build up an upward fining sequence. The nature of the fine overbank part of the braided stream cycle is as complex as the coarse lower, so that a highly variable vertical sequence of lithological types is likely to be constructed.Upward fining cycles are also built by some fine braided streams but they are the product of a single flood rather than lateral channel migration. Braided stream deposits are distinguishable from those of small, coarse meandering stream deposits by the presence of inner accretionary banks in the latter, and inner channels in the former.

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