Dynamics and behaviour of suspended sediment in macrotidal estuaries along the south coast of the English Channel

Avoine, Jacques; Larsonneur, Claude

doi:10.1016/0278-4343(87)90033-1

Cited by 22 publications

(11 citation statements)

References 5 publications

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“…10; Avoine & Larsonneur, 1987;Kirkby, 1987;Gao et al, 1990;Ke et al, 1996;Plater et al, 2000). Large volumes of sediment suspension entrained by storms and tides can be entrapped in bays with no significant fluvial discharges, and may be subject to circulation by remnant turbulence and residual currents.…”

Section: The Palaeobay Environmentmentioning

confidence: 99%

Anatomy of a Transgressive Systems Tract Revealed by Integrated Sedimentological and Palaeoecological Study: The Barcellona Pozzo Di Gotto Basin, Northeastern Sicily, Italy

Messina

Rosso

Sciuto

et al. 2007

Sedimentary Processes, Environments and Basins

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The Barcellona Pozzo di Gotto Basin of northeastern Sicily, central Mediterranean, is a Plio-Pleistocene peri-Tyrrhenian shelf embayment that formed by the collapse and marine inundation of bedrock fault-blocks in response to regional tectonic extension. The study focuses on the well-developed transgressive systems tract of the lower bay-fill sequence. This succession of middle Pliocene to Lower Pleistocene marine deposits has a mixed siliciclastic to bioclastic composition and is ~73 m thick in mid-bay outcrop section. The deposits are sandy to silty facies indicating a wavedominated bay rich in suspended sediment and influenced by storms and tidal currents. Facies associations represent upper and lower shoreface, offshore-transition and mid-bay offshore zones. The abundance of silty to sandy suspension is attributed to the entrapment of fine sediment entrained by storms and tides and possibly derived from nearby streams. The supply of sediment from the bay's shoreline zone probably combined with fine-grained sediment drift from offshore areas, as is also suggested by admixtures of outer circalittoral benthic microfauna. Facies-based estimates indicate a water depth of ≤ 25 m for the mid-bay area, with a mean depth of ~10 m for fairweather wave base and ~15-16 m for storm wave base. The shallow bay hosted circalittoral benthic fauna typical of deeper water Mediterranean shelves, which can be attributed to the high turbidity of the bay water (limited light penetration).The stratigraphic organization of the facies associations and their fauna assemblages reveals that the succession consists of six parasequences, or transgressive-regressive cycles, bounded by marine flooding surfaces and showing an overall deepening upward trend. The parasequences are 4-17 m thick, and some include well-developed transgressive deposits and also a relatively thick mid-cycle condensation zone. The latter indicates a prolonged balance between the rates of accommodation development and its filling by slow aggradation. Palaeoecological and taphonomic criteria defining a condensation maximum allow the maximum flooding surface to be identified, typically in the upper part of the mid-cycle condensation zone. The parasequences have time spans of ~300 kyr and correlate with the 4th-order regional sequences recognized in the central Mediterranean. Accordingly, they are inferred to be the local equivalents of these high-frequency sequences, owing their facies architecture to a relatively high rate of tectonic subsidence in the peri-Tyrrhenian coastal region of northern Sicily. These would thus be type 2 sequences involving little or no fall in relative sea level and hence developed as parasequences. The integration of sedimentological, biostratigraphic, palaeoecological and taphonomic data proves to be a powerful method for high-resolution sequence stratigraphy and palaeoenvironment reconstruction, including sediment dynamics, palaeogeography and bathymetric changes.

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Section: The Palaeobay Environmentmentioning

confidence: 99%

Anatomy of a Transgressive Systems Tract Revealed by Integrated Sedimentological and Palaeoecological Study: The Barcellona Pozzo Di Gotto Basin, Northeastern Sicily, Italy

Messina

Rosso

Sciuto

et al. 2007

Sedimentary Processes, Environments and Basins

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“…Small particles tend to be permanently suspended, while larger ones periodically settle to the bed and become resuspended during a tidal cycle. Situations where the enhanced particle residence times combine with a large suspended organic load and significant resuspensiondriven redox cycling provide substrates for enhanced microbial activity [Owens, .1986;Avoine and Larsonneur, 1987;Plummet et al, 1987;Uncles and Stephens, 1993;Balls et al, 1996;Crump and Baross, 1996]. Active N20 cycling at the turbidity maximum of the Humber estuary, United Kingdom, has been interpreted in these terms , and the possibility that such sites also are important for the active bacterial cycling of CH4 deserves scrutiny.…”

Section: ] and The Thermal Response Of Natural Wetlands [Hogan Amentioning

confidence: 99%

Methane in the southern North Sea: Low‐salinity inputs, estuarine removal, and atmospheric flux

Upstill‐Goddard¹,

Barnes²,

Frost³

et al. 2000

Global Biogeochemical Cycles

161

110

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Abstract. Dissolved CH 4 was measured in coastal waters of the southern North Sea, in two adjacent U.K. estuaries with well-defined turbidity maxima (Humber and Tyne) and in their associated river catchments, during a series of campaigns covering the period 1993-1999. In general, samples from all three environments were significantly to highly CH4 enriched relative to atmospheric air. Observed river water concentrations,-33-152 nmol L -• (940-4305% saturation) for the Humber river catchment and ---3-62 nmol L '• (86-1754% saturation) in the river Tyne, were within but toward the low end of the range of CH4 concentrations in river waters world wide. In sea waters from the outer Wash estuary (U.K. coast) and adjacent to the Dutch coast, CH4 was highly but nonlinearly correlated with salinity, consistent with strong CH 4 removal from river and/or estuarine CH4 sources influencing these locations. In transects along the Humber and Tyne estuaries, CH4 was highly negatively nonconservative, confirming the estuarine removal hypothesis. lost globally to gas exchange in estuaries, increasing previous such estimates by-8-50 %. However, as it is based on data that exclude the possibility of elevated CH 4 levels at estuarine turbidity maxima, even this revision is likely to be conservative. Detailed studies of CH4 distributions in major world estuaries would now be required in order to successfully reevaluate the CH4 budget of the coastal marine atmosphere.

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“…Embayments and estuaries often act as sediment traps or filters which retain material through tidal processes (Schubel & Carter, 1984;Avoine & Larsonneur, 1987; Kirby, 1987). These trapping processes are better identified in embayments where fluvial water and sediment discharges are negligible, in comparison with those from an adjacent marine source.…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics and sediment dynamics of The Wash embayment, eastern England

Evans

Collins

1996

Sedimentology

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Water and sediment movement in The Wash embayment has been determined from an extensive set of data, consisting of tidal current readings and suspended sediment concentration measurements. Instantaneous and residual currents in the embayment show a distinct lateral inhomogeneity, whereas vertically the water column is almost homogenous. The central deep water area (30–40 m) of the embayment is dominated by a residual landward water movement, whilst on the margins, the residual movement is seaward. Sediment is supplied predominantly in suspension from the north, through the northern extremity of Boston Deep. Suspended sediment pathways are coincident with the spring tide water movements and the subtidal channels act as the main conduits. Approximately 6·8 × 106 tonnes yr−1 of suspended sediments are supplied to the embayment from offshore areas. Bedload sediment supply is of lesser importance, ∼ 1·4 × 104 tonnes yr−1. Whereas suspended sediment movement appears to be the dominant mode of transport throughout the embayment, bedload transport is important in reforming the sea bed into a variety of bedforms which are particularly well developed on the margins of channels and shoals.

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Dynamics and behaviour of suspended sediment in macrotidal estuaries along the south coast of the English Channel

Cited by 22 publications

References 5 publications

Anatomy of a Transgressive Systems Tract Revealed by Integrated Sedimentological and Palaeoecological Study: The Barcellona Pozzo Di Gotto Basin, Northeastern Sicily, Italy

Anatomy of a Transgressive Systems Tract Revealed by Integrated Sedimentological and Palaeoecological Study: The Barcellona Pozzo Di Gotto Basin, Northeastern Sicily, Italy

Methane in the southern North Sea: Low‐salinity inputs, estuarine removal, and atmospheric flux

Hydrodynamics and sediment dynamics of The Wash embayment, eastern England

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