The rock floor of the English Channel and its significance for the interpretation of marine unconformities

Curry, Dennis

doi:10.1016/s0016-7878(89)80053-7

Cited by 23 publications

(9 citation statements)

References 26 publications

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“…In some areas, however, it could be associated with lag deposits. Moreover, the BR is an unconformity that represents a significant stratigraphic hiatus, observed widely over the English Channel (Curry, 1989; Stride, 1991; Evans, 1992).…”

Section: Seismic Resultsmentioning

confidence: 99%

Morphology and internal structure of sand shoals and sandbanks off the Dorset coast, English Channel

Bastos¹,

Collins²,

Kenyon

2003

Sedimentology

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The morphology and internal structure of sand shoals and sandbanks around a coastal headland (Portland Bill, southern UK) are described on the basis of sidescan sonar and high‐resolution seismic data sets. Morphological and architectural evidence, combined with the spatial distribution and nature of the bedrock surface, indicates that the evolution of these deposits, especially the sandbanks, may not only be hydrodynamically controlled but also morphologically controlled. The internal structure of the sand shoals reveals a simple pattern of clinoforms dipping in the same direction as their steeper profile. In contrast, the internal structure of the sandbanks reveals that their lower seismic units consist of a sedimentary core interpreted as the remains of a lowstand deposit or an early stage of the bank development under different prevailing hydrodynamic conditions. The present morphology of the sandbanks is represented by upper seismic units characterized by large‐scale sandwave foresets dipping at 6–8°. The nature and morphology of the bedrock surface may also influence the development of sandbanks in some cases. For example, to the west of Portland Bill, the morphology of the bedrock surface (basal reflector) restricts the development of the Portland Bank. This information may explain the asymmetric evolution of sandbanks around Portland Bill.

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Section: Seismic Resultsmentioning

confidence: 99%

Morphology and internal structure of sand shoals and sandbanks off the Dorset coast, English Channel

Bastos¹,

Collins²,

Kenyon

2003

Sedimentology

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“…Indeed, the more ancient infilling deposits could be as old as Pliocene. Once the westernmost troughs were filled, the Western Channel abrasion surface was shaped by active subaerial processes (mostly periglacial) and submarine processes during the numerous Upper Pliocene and Quaternary regressive and transgressive phases (Curry 1989). Northeastwards, the deeper main trough, i.e.…”

Section: Resultsmentioning

confidence: 99%

Detailed survey of the western end of the Hurd Deep (English Channel): new facts for a tectonic origin

Lericolais

Guennoc

Auffret

et al. 1996

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During the 'S~dimanche 2' survey, a study of the western end of the Hurd Deep was carried out using new high-resolution geophysical techniques. The obtained results, i.e. bathymetry, acoustical imaging and seismic profiling, determine a tectonic control on the first excavation of Hurd Deep, a complex infilling and present-day sediment dynamics.In size and geometry, the Hurd Deep is a unique feature in the English Channel, terminating abruptly at its western end. It is incised into Jurassic and Late Cretaceous sediments. Except for the trough itself, the sea floor is extensively levelled at a depth between 70 and 90m.The Hurd Deep infill, revealed by high-resolution seismic data, is characterized by a set of five main sequences. The thickness of the infill averages 80 m along the axis of the trough and reaches a maximum of 140m. The side-scan sonar mosaic shows active sediment dynamics characterized by the presence of dunes on the southern part of the present trough.A Neogene tectonic origin for the Hurd Deep and the interplay of erosion and sedimentation during the last glacial and interglacial periods are presented in terms of geomorphology and sequence stratigraphy.Even though several surveys have been carried out along the Hurd Deep axis (

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“…The influence of solid geology on the patterns of sediment transport and deposition, is evidently greater in the absence of any significant sedimentary cover; this, in turn is related to the differential erosion potential of the seabed, due to the presence/exposure of different rock types and structures and the development of solid geomorphological features (bedrock ridges) on the seafloor (Donovan & Stride 1961;Curry 1989;Evans 1992;Bastos et al 2002). An assessment of the coastal geomorphology is relevant also at this stage of the investigation, as it provides information on the various offshoreonshore interactions as well as on the coastal sediment reservoirs, circulation cells and transport patterns.…”

Section: Solid Geology and Coastal Geomorphologymentioning

confidence: 99%

“…Sediments of low textural 'maturity' may show unpredictable changes in the grain-size parameters during the course of transport, in response to abrasion; they may introduce uncertainties concerning their hydraulic behaviour if mechanical sieving is used in their grain-size analysis (Flemming 1977). Finally, thin deposits may be subject to 'contamination', by sediments produced by the erosion of the underlying bedrock (Curry 1989). …”

Section: Sedimentological Indicators--grain Size Trend Analysismentioning

confidence: 99%

Seabed sediment transport pathway investigations: review of scientific approach and methodologies

Velegrakis

Collins

Bastos

et al. 2007

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An understanding of the geomorphological evolution of the coastal and inner continental shelf environments, in response to natural and/or anthropogenic forcings, depends upon a comprehensive knowledge of the prevailing sediment dynamics. In this contribution, selected methods/tools that can be used to study seabed mobility/transport patterns, are described and these all reviewed in relation to their inherent limitations.The geological, morphological, hydrodynamic and sedimentary information (the environmental framework) necessary to develop a general understanding of the areas investigated are identified. This preliminary information prescribes the investigative tools to be utilized subsequently, i.e. the collection/analysis of data; these can define geomorphological and sedimentological indicators of sediment transport, hydrodynamic/sediment transport field observations and numerical simulations.The results derived from the various methods can be used then independently or, preferably in combination, to establish conceptual models of seabed sediment dynamics over the investigated area. The coherence between the outputs of the different methods/tools controls the confidence level (high, medium or low) of the models. This approach is illustrated in relation to case studies from the southern UK inner continental shelf.

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The rock floor of the English Channel and its significance for the interpretation of marine unconformities

Cited by 23 publications

References 26 publications

Morphology and internal structure of sand shoals and sandbanks off the Dorset coast, English Channel

Morphology and internal structure of sand shoals and sandbanks off the Dorset coast, English Channel

Detailed survey of the western end of the Hurd Deep (English Channel): new facts for a tectonic origin

Seabed sediment transport pathway investigations: review of scientific approach and methodologies

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