Siliciclastic Back-Barrier Tidal Flats

Flemming, Burghard W.

doi:10.1007/978-94-007-0123-6_10

Cited by 58 publications

(46 citation statements)

References 102 publications

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“…Dolomicrites exhibit ripples with cross-laminations and flaser bedding requiring deposition under slightly more agitated conditions in shallow peritidal settings. Lenticular wavy to thin flat beds are commonly reported from modern tidal flat deposits (Davis, 2012;Flemming, 2012). The presence of intraformational mud-pebble conglomerates and breccias in association with crinkle spar-filled cracks (pedogenetic structures), solution cavities parallel to the bedding planes, and restricted to rare ostracod and gastropod biota allow comparison of F2 to Member A of supratidal deposits of a Lofer Cycle observed in the Late Triassic of Austria (Fischer, 1964;Shinn, 1983;Fl€ ugel, 1984).…”

Section: Bay System To Tidal Mud Flatmentioning

confidence: 99%

Microbial deposits in the aftermath of the end‐Permian mass extinction: A diverging case from the Mineral Mountains (Utah, USA)

et al. 2015

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International audienceData indicate that the morphologies of the three microbialite associations are controlled primarily by accommodation, hydrodynamics, bathymetry and grain supply. This study suggests that microbial constructions are controlled by changes between trapping and binding versus precipitation processes in variable hydrodynamic conditions. Due to the presence of numerous metazoans associated with microbialites throughout the Smithian increase inaccommodation and Spathian decrease in accommodation, the commonly assumed anachronistic character of the Early Triassic microbialites and thetraditional view of prolonged deleterious conditions during the Early Triassic time interval is questioned

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Section: Bay System To Tidal Mud Flatmentioning

confidence: 99%

Microbial deposits in the aftermath of the end‐Permian mass extinction: A diverging case from the Mineral Mountains (Utah, USA)

et al. 2015

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“…Tidal channels cut through lagoons and estuaries forming complex dendritic networks, in which minor creeks usually converge into a major channel (Ashley & Zeff, ; D'Alpaos et al ., ; Hughes, ; Zhou et al ., ). Tidal meandering channels can be either periodically or constantly submerged by water, being located in the intertidal and subtidal zone, respectively (Bartholdy, ; Flemming, ). Sedimentological models for tidal point bars mainly derive from modern intertidal meanders (Land & Hoyt, ; Bridges & Leeder, ; Barwis, ; De Mowbray, ; Fenies & Faugères, ; Choi et al ., ; Pearson & Gingras, ; Choi, ; Fruergaard et al ., ; Johnson & Dashtgard, ), which drain tidal flat areas that are commonly exposed during low tide.…”

Section: Introductionmentioning

confidence: 99%

Tidal currents and wind waves controlling sediment distribution in a subtidal point bar of the Venice Lagoon (Italy)

et al. 2019

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The present study aims to improve current understanding of the sedimentation of subtidal point bars, analyzing interaction between tidal currents and waves in shaping a submerged meander bend of the microtidal Venice Lagoon (Italy), and it is based on coupling of sedimentological studies, geophysical analyses and numerical modelling. The Venice Lagoon is characterized by an average depth of about 1Á5 m over subtidal platforms and a mean tidal range of about 1Á0 m. The morphodynamic evolution of the lagoon is strongly affected by intense seasonal windstorms, which promote the formation of wind waves triggering sediment resuspension and bottom erosion. The study channel is 70 to 100 m wide, it has a radius of curvature of about 260 m and cuts through a permanently submerged subtidal platform. Water depth ranges from 1Á0 to 5Á0 m below mean sea level on the subtidal platform and channel thalweg, respectively. Different from classical architectural models, the study point-bar beds do not show sigmoidal geometries, but consist of horizontally-bedded deposits abruptly overlying clinostratified beds. Sedimentation in the study bar is hypothesized to stem from the interaction between the in-channel secondary helical flow, as for most meander bends, and wave winnowing of the subaqueous overbank areas. Laterally accreting point-bar deposits point out that the curvature-induced helical flow redistributed sediment from the channel thalweg to the bar top and contributed to the development of the 'classical' fining-upward grain size trend. The marked truncation surface, separating clinostratified bar deposits from overlying horizontally-bedded platform sediments is interpreted here as due to bar top wave-winnowing, which also possibly promoted bank collapses. In the proposed model, sediments remobilized from bar top and subaqueous overbank areas were transported into the channel, forming peculiar 'apronlike' accumulations, where sand accumulated through avalanching processes and mud settled down from suspension.

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“…The grain size distribution of samples shows no spatial (vertical, horizontal) trends (Figures a and b). These observations are atypical of what is found for many tidal flats: As fluid velocity and shear stress diminish away from the tidal channel, sediment deposit thickness and grain size typically reflect this gradient and systematically thin and fine, respectively (Flemming, ; Friedrichs, ). Indeed, there seems to be no relation in terms of marine‐derived sediment thickness and distance from the primary tidal channel (Figure b).…”

Section: Discussionmentioning

confidence: 73%

Infilling Abandoned Deltaic Distributary Channels Through Landward Sediment Transport

et al. 2020

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Upon avulsion, abandoned deltaic distributary channels receive water and sediment delivered by a tie channel, overbank flow, and by tidal inundation from the receiving basin. The transport and deposition of sediment arising from this latter input have important impacts on delta development yet are not well constrained from field observations or numerical models. Herein, the Huanghe (Yellow River) delta, China, is used as a case study to evaluate how marine‐sourced sediment impacts abandoned channel morphology. For this system, artificial deltaic avulsions occur approximately decadally; the abandoned channels are inundated by tides, and deposition of sediment transforms the channel into a mudflat. Field data were collected from a channel abandoned 20 yr ago and included cores that penetrated the tidally deposited mud and antecedent fluvial channel sediment, topography, bathymetry surveys, and detailed time series monitoring of hydrodynamic conditions within the tidal channel and adjacent mudflat. These data are used to validate a model that predicts the rate of accumulation and grain size of sediment delivered from the tidal channel to the mudflat. The thickness of the marine‐sourced mud differs spatially by an order of magnitude and is primarily impacted by antecedent channel topography. Sediment has aggraded to an elevation approaching mean high tide, which is likely the limit of fill. As this elevation is below antecedent levees, assuming stationary relative sea level, the abandoned channel will remain a topographic low on the delta landscape and is therefore susceptible to reoccupation during future avulsions.

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Siliciclastic Back-Barrier Tidal Flats

Cited by 58 publications

References 102 publications

Microbial deposits in the aftermath of the end‐Permian mass extinction: A diverging case from the Mineral Mountains (Utah, USA)

Microbial deposits in the aftermath of the end‐Permian mass extinction: A diverging case from the Mineral Mountains (Utah, USA)

Tidal currents and wind waves controlling sediment distribution in a subtidal point bar of the Venice Lagoon (Italy)

Infilling Abandoned Deltaic Distributary Channels Through Landward Sediment Transport

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