Seven cores were collected from different sediment zones of tidal flats at Xinyanggang in north Jiangsu province in August 2007. Sediment rates of the cores and radioisotopes distribution in surface sediment in different zones of the tidal flat were
calculated from the 137Cs and 210Pb activities in sediments cores. The results indicated that each tidalzone had experienced different evolution phases. 137Cs and 210Pb activities on the superficial layer of the cores varied spatially and the reason
was discussed. The characteristics of 137Cs and 210Pb in the cores reflected various depositional dynamical environments in different tidalzones and gave information on the different evolvement phases of the tidalzones.
The tidal character of the formation of Tegelen in northern Belgium
Belgique ; Géographie de l'Europe ; Lagune ; Littoral ; Pléistocène ; Quaternaire zones moyennes ; Sédimentation ; Zone intertidale
Small scale current ripples with opposed high-angle cross lamination indicate tidal movements during deposition. A fresh or brackish subtidal environment is suggested. - (AIS)
A parameterization of the wavelength of tidal dunes
Atlantic Ocean ; Coastal dynamics ; Coastal environment ; Hydrodynamics ; Intertidal zone ; Model ; North Sea ; Sand wave ; Sediment transport ; Tidal current ; Tidal dune
Atlantique ; Courant de marée ; Dune de marée ; Dynamique littorale ; Hydrodynamique ; Littoral ; Mer du Nord ; Modèle ; Transport sédimentaire ; Vague de sable ; Zone intertidale
In this study, the model of Besio et al. (2006) is used to generate a database that allows a parameterization of the length of tidal dunes to be obtained. The predictions are then analysed and a formula is proposed to estimate the wavelength
of tidal dunes as a function of the parameters of the problem. The wavelength of the dunes is found to increase when the water depth is increased and/or the strength of the tidal current is decreased. On the other hand, the size of the bottom material
(if medium sand is considered) and the tidal ellipticity are found to have a relatively small influence on the length of the bottom forms. The formula proposed provides results which are consistent with field observations.
In this study, field settling velocities of the suspended sediment have been measured during two tidal periods, in Ho Bugt, on October 17, 1989 and July 24, 1990. During both periods, the current velocity, salinity, water temperature and suspended
The effect of bidirectional flow on tidal channel planforms
Aerial photography ; Bank erosion ; California ; Channel geometry ; Coastal environment ; Intertidal zone ; Meander ; Model ; Tidal creek ; Tidal current ; Tidal marsh ; United States of America
California ; Chenal de marée ; Courant de marée ; Erosion des berges ; Etats-Unis ; Géométrie hydraulique ; Littoral ; Marais littoral ; Modèle ; Méandre ; Photographie aérienne ; Zone intertidale
Field surveys and aerial photographs were used to characterize the planform of tidal channels at China Camp Marsh in the San Francisco Bay, California. To model the planform evolution, the AA. assume that the topographic curvature of the channel
centreline is a key element driving meander migration. The curvature calculations, combined with data from numerous cross-sections along the tidal channel, were used to parameterize a computer model. With this model, based on recent theoretical work
Bio-geomorphic effects on tidal channel evolution : impact of vegetation establishment and tidal prism change
Aerial photography ; Biogeomorphology ; Channel geometry ; Coastal environment ; Coastal sedimentation ; Estuary ; Europe ; Intertidal zone ; Northwestern Europe ; Photointerpretation ; Plant colonization ; Tidal marsh ; Time series ; Vegetation
; Végétation ; Zone intertidale
The long-term (10-100 years) evolution of tidal channels is generally considered to interact with bio-geomorphic evolution of the surrounding intertidal platform. Here the AA. studied how the geometric properties of tidal channels (channel drainage
density and channel width) change as (1) vegetation establishes on an initially bare intertidal platform and (2) sediment accretion on the intertidal platform leads to a reduction in the tidal prism (i.e. water volume that during a tidal cycle floods
to and drains back from the intertidal platform). Based on a time series of aerial photographs and digital elevation models, the AA. derived the channel geometric properties at different time steps during the evolution from an initially low-elevated bare tidal
experiments are being concluded to determine the related effects of salts. The greatest amount of expansion and contraction was at the high tidal-level in the argillite and at the mid-tidal level in the basalt, which is consistent with previously measured
Sediments and water fluxes in a muddy coastline : interplay between waves and tidal channel hydrodynamics
Coastal dynamics ; Coastal environment ; Intertidal zone ; Louisiana ; Sediment transport ; Storm wave ; Tidal creek ; United States of America ; Wave ; Wind
Chenal de marée ; Dynamique littorale ; Etats-Unis ; Littoral ; Louisiana ; Onde de tempête ; Transport sédimentaire ; Vague ; Vent ; Zone intertidale
To investigate the processes that regulate sediment fluxes in muddy coastlines, the AA. measured tidal velocity and sediment concentration in Little Constance Bayou, a tidal channel in the Rockefeller State Wildlife Refuge, Louisiana, USA. The tidal
Colonisation of Spartina on a tidal water divide, Danish Wadden Sea
Années 1945-2000 ; Biogéographie ; Colonisation végétale ; Danemark ; Dynamique de la végétation ; Glace ; Littoral ; Marais salant ; Mer de Wadden ; Niveau marin ; Photo-interprétation ; Spartina ; Zone intertidale
The spread of Spartina on a tidal water divide has been followed in subsequent aerial photos. Spartina first appeared in the area in 1964, it spread rapidly to 1976. From 1976 to 1988 a significant die-back is observed. This die-back was more than
recovered in 1995. The die-back period had a number of cold winters, which points to the role of ice in the Spartina die-back. In comparison with the local tidal range, possible future planting of Spartina in salt marsh management strategies should take
place at levels, which are inundated no more than 5 hours per tidal cycle.
Spatial and temporal variability of sediment accumulation rates on two tidal flats in Lister Dyb tidal basin, Wadden Sea, Denmark
Danemark ; Datation ; Datation C 14 ; Littoral ; Luminescence stimulée optiquement ; Mer des Wadden ; Niveau marin ; Taux de sédimentation ; Variation spatiale ; Zone intertidale
C 14 dating ; Coastal environment ; Dating ; Denmark ; Intertidal zone ; Optically stimulated luminescence ; Sea level ; Sedimentation rate ; Spatial variation
Absolute chronologies, obtained using optically stimulated luminescence (OSL) and radiocarbon dating (14C), are presented from 7 sediment cores in an aggrading tidal lagoon. On the mudflat in the western and sheltered part of the lagoon
the intertidal sedimentation has followed the rate of relative sea-level rise, at least over the last ∼2000 years, whereas the trends in sediment accumulation rates on the sandy tidal flat in the eastern and exposed part of the lagoon are less clear. The AA
. conclude, however, that sediment accumulation on the 2 tidal flats in Lister Dyb tidal basin generally has kept pace with the rising sea-level. This conclusion seems to apply over the last few centuries and is generally true over the last few millennia
Discordant 14C ages from buried tidal-marsh soils in the Cascadia subduction zone, southern Oregon coast
Peaty, tidal-marsh soils interbedded with estuarine mud in late Holocene stratigraphic sequences near Coos Bay, Oregon, may have been submerged and buried during great (M>8) subduction earthquakes, smaller localized earthquakes, or by nontectonic
processes. Radiocarbon dating might help distinguish among these alternatives by showing that soils at different sites were submerged at different times along this part of the Cascadia subduction zone.
Egy külonleges arapaly ovezet. A Watt-tenger vidéke. (A peculiar tidalzone. The Waddenzee region)
Géographie de l'Europe ; Géomorphologie littorale ; Ligne de rivage ; Littoral ; Mer des Wadden ; Mer du Nord ; Milieu intertidal ; Pays-Bas ; Wadden ; Zone intertidale
and the complex coastline with fjords and islands. Boundary conditions at the oceanic sides of the model domain are obtained by interpolation from a larger scale tidal model covering the Nordic Sea. Duscussion of the results.
Tidal channel meander formation by depositional rather than erosional processes : examples from the prograding Skagit River Delta (Washington, USA)
Aerial photography ; Channel geometry ; Chronosequence ; Delta ; Geographical information system ; Intertidal zone ; Meander ; Tidal creek ; Twentieth Century ; United States of America ; Washington State
Chenal de marée ; Chronoséquence ; Delta ; Etats-Unis ; Géométrie hydraulique ; Méandre ; Photographie aérienne ; Siècle 20 ; Système d'information géographique ; Washington State ; Zone intertidale
Geographic information system (GIS) analysis of historical aerial photographs of the Skagit Delta marshes provides examples of an alternative meander forming process in a rapidly prograding river delta: deposition-dominated tidal channel meander
formation through a developmental sequence beginning with sandbar formation at the confluence of a blind tidal channel and delta distributary, proceeding to sandbar colonization and stabilization by marsh vegetation. The transition from confluence sandbar
to tidal channel meander can take as little as 10 years, but more typically occurs over several decades. This depositional blind tidal channel meander formation process is part of a larger scale systemic depositional process of delta progradation
Sulphate reduction as a geomorphological agent in tidal marshes (Great Marshes at Barnstable, Cape Cod, USA)
Brackish environment ; Coastal environment ; Environmental degradation ; Hydrochemistry ; Intertidal zone ; Massachusetts ; Model ; Salinity ; Tidal marsh ; United States of America ; Vegetation ; Water temperature
Dégradation de l'environnement ; Etats-Unis ; Hydrochimie ; Littoral ; Marais littoral ; Massachusetts ; Milieu saumâtre ; Modèle ; Salinité ; Température de l'eau ; Végétation ; Zone intertidale
Many tidal marsh surfaces feature water-filled depressions, known as salt pans (shallow) or ponds (deeper). In the Great Marshes at Barnstable, Cape Cod, pond formation is an active process. The AA. hypothesize that degradation of organic matter
Renewal of tidal forests in Washington State after a subduction earthquake in A.D. 1700
Alaska ; Dendrochronologie ; Dynamique de la végétation ; Epicéa ; Estuaire ; Etats-Unis ; Etude comparée ; Forêt ; Paléobiogéographie ; Paléogéographie ; Subduction ; Séisme ; Washington State ; Zone intertidale
Alaska ; Comparative study ; Dendrochronology ; Earthquake ; Estuary ; Forest ; Intertidal zone ; Palaeobiogeography ; Palaeogeography ; Spruce ; Subduction ; United States of America ; Vegetation dynamics ; Washington State
into tidal flats. Postearthquake tides, and perhaps uplift as well, then created land on which new trees became established. Such renewal, seen also in Alaska after an earthquake in 1964, probably explains why Washington's tidal forests now contain few
Chine ; Delta ; Dynamique littorale ; Littoral ; Marais littoral ; Niveau marin ; Taux de sédimentation ; Yangzi ; Zone intertidale
Progradation rates of tidal flats at the Chiangjiang River mouth, over different periods were examined, based on surveys and historical records. Results and discussion : long-term, medium-term and short-term evolution, future prospect of evolution
The AA. selected Chongming east tidal flat as the typical Yangtze estuary intertidal flat research site, focused on investigating the relationship between sediments organic content variation and S. mariqueter growing stage, and tried to expand
the study of carbon cycle in the Yangtze estuary and other estuarine and coastal tidal flats.