A new hypothesis and exploratory model for the formation of large-scale inner-shelf sediment sorting and “rippled scour depressions”

2004 ◽  
Vol 24 (3) ◽  
pp. 295-315 ◽  
Author(s):  
A.Brad Murray ◽  
E.Robert Thieler
Keyword(s):  
Large Scale ◽  
Inner Shelf ◽  
Shelf Sediment ◽  
Sediment Sorting ◽  
New Hypothesis ◽  
Exploratory Model

scholarly journals Conceptualising and mapping coupled estuary, coast and inner shelf sediment systems

Geomorphology ◽  
2016 ◽  
Vol 256 ◽  
pp. 17-35 ◽  
Author(s):  
Jon French ◽  
Helene Burningham ◽  
Gillian Thornhill ◽  
Richard Whitehouse ◽  
Robert J. Nicholls
Keyword(s):  
Inner Shelf ◽  
Shelf Sediment

Nearshore—Inner Shelf Sediment Exchange on the NSW Central Coast

2001 ◽  
Author(s):  
Peter Evans ◽  
David Hanslow ◽  
Aaron Coutts-Smith ◽  
Zai-Jin You
Keyword(s):  
Central Coast ◽  
Inner Shelf ◽  
Shelf Sediment

A preliminary OSL chronology for coastal dunes on Moreton island, Queensland, Australia – Marginal deposits of A large-scale quaternary shelf sediment system

2015 ◽  
Vol 105 ◽  
pp. 79-94 ◽  
Author(s):  
Brendan P. Brooke ◽  
Timothy J. Pietsch ◽  
Jon M. Olley ◽  
Craig R. Sloss ◽  
Malcolm E. Cox
Keyword(s):  
Large Scale ◽  
Coastal Dunes ◽  
Shelf Sediment

Monitoring inner shelf sediment transport using fluorescent sand tracers: an example from the south coast of Portugal 

2021 ◽  
Author(s):  
João Cascalho ◽  
Rui Taborda ◽  
Marcos Rosa ◽  
Erwan Garel ◽  
Sebastião Teixeira ◽  
...  
Keyword(s):  
Sediment Transport ◽  
Tracer Experiment ◽  
Current Data ◽  
Automated Image Analysis ◽  
South Coast ◽  
Inner Shelf ◽  
Shelf Sediment ◽  
Ongoing Work ◽  
Coated Sand

<p>The continuous need for beach nourishment requires a detailed understanding of the sediment transport characteristics at the shelf borrow sites, to assess their recovery rate and to evaluate the long-term sustainability of these operations. </p><p>The main objective of this work is to assess sediment transport conditions at an inner shelf borrow site exploited to nourish a beach located at the updrift boundary of the same sedimentary cell (Belharucas, Albufeira, south coast of Portugal).</p><p>The work is supported by a sand tracer experiment, where 600 kg of coated sand with fluorescent ink was deposited (August 2020) by divers at 11 m depth (referred to the mean sea level). Periodic sediment sampling using a Van Veen grab was performed using an adaptative sampling grid that accounted for tracer’s dispersion trough time. The samples were washed and dried in laboratory and tagged particles were automatically identified using an automated image analysis procedure based on ultraviolet lighting.</p><p>Preliminary results show that sediment transport is dominated by a eastward component,probably related with the energetic events from the SW. Ongoing work relates the tracer’s displacement with ADCP (wave and current) data measured nearby the borrow site during the experiment.</p><p> </p><p>The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – IDL and ECOEXA project (MAR-01.04.02-FEAMP-0016).</p><p> </p><p> </p>

Late Quaternary seismic stratigraphy of the inner shelf seaward of the Tuktoyaktuk Peninsula, Canadian Beaufort Sea

1989 ◽  
Vol 26 (10) ◽  
pp. 1990-2002 ◽  
Author(s):  
Arnaud Héquette ◽  
Philip R. Hill
Keyword(s):  
Sea Level ◽  
Land Surface ◽  
Large Scale ◽  
Late Quaternary ◽  
Lower Boundary ◽  
Beaufort Sea ◽  
Seismic Stratigraphy ◽  
Inner Shelf ◽  
The Holocene ◽  
Late Wisconsinan

This paper describes the seismic stratigraphy of the Quaternary sediments on the inner shelf (< 20 m water depth) of the Canadian Beaufort Sea, seaward of the Tuktoyaktuk Peninsula. Two regional unconformities and three seismic sequences are defined from the high-resolution seismic records. The deeper sequence (sequence III) is characterized by large-scale cross-beds. This sequence has been correlated with the Tingmiark Sand lithostratigraphic unit, which was previously defined farther offshore and is thought to be a glaciofluvial unit deposited during lower-than-present sea-level conditions in the Late Wisconsinan. The lower boundary of the overlying sequence (sequence II) is an unconformity (u/c 2), interpreted as the pre-transgression land surface. Sequence II is discontinuous and consists of localized basin-fill and channel-fill units. Most of these are remnants of thermokarst lakes partially eroded during the Holocene transgression. This sequence is separated from the uppermost sequence (sequence I) by another unconformity (u/c 1), which is the shoreface erosion surface generated by the Holocene sea-level rise. Sequence I is composed of a transgressive sand sheet overlain, in deeper areas, by recent marine muds. Seaward of Hutchison Bay, a large subbottom depression within sequence III in interpreted as a Late Wisconsinan fluviatile channel. According to our seismic interpretation, the Tuk Phase morainal and glaciofluvial deposits existing onland on the Tuktoyaktuk Peninsula, previously assigned to the Early Wisconsinan, would be of Late Wisconsinan age.

Holocene variability of the northeastern Laurentide Ice Sheet in the Clyde Inlet area, western Baffin Bay, from radiogenic isotope records in marine sediments

2021 ◽  
Author(s):  
Johanna Hingst ◽  
Claude Hillaire-Marcel ◽  
Friedrich Lucassen ◽  
Christoph Vogt ◽  
Emmanuel Okuma ◽  
...  
Keyword(s):  
Large Scale ◽  
Isotope Composition ◽  
Ice Sheet ◽  
Temporal Variations ◽  
Spatial And Temporal Variations ◽  
Laurentide Ice Sheet ◽  
Baffin Island ◽  
Baffin Bay ◽  
Radiogenic Isotope ◽  
Shelf Sediment

&lt;p&gt;The reconstruction of late glacial ice sheet fluctuations helps understanding and modelling the local glacio-isostatic adjustment as well as global eustatic changes. From this viewpoint, the large-scale spatial and temporal variations of the Fox Basin-Baffin Island ice dome (NE Laurentide Ice Sheet, Canada) have been well documented. However, high frequency Holocene fluctuations and final decay of it are still poorly documented. We have thus investigated the behaviour of one of its eastern outlet glaciers in the Clyde Inlet fjord, northeastern Baffin Island. The reconstruction of ice sheet margin fluctuation is based on the radiogenic isotope composition (Sr-Pb-Nd) and mineral assemblage of detrital sediments in two marine cores raised within and off the Clyde Inlet (GeoB22346-3, Clyde Inlet head; GeoB22357-3, adjacent continental shelf). Radiogenic isotope ratios and bulk mineral assemblages from such sites are imprints of bedrock erosion along the active ice margin, as well as along ice-streams and subglacial drainage patterns. They may thus be used for the reconstruction of spatial and temporal variations in meltwater discharge into Baffin Bay and of the position of the active margin fluctuations inland. The location of the two sediment cores also informs on the traceability of radiogenic isotope signals from proximal to more distal areas of sediment deposition. Changes in mineralogical and radiogenic isotope compositions at the proximal core site suggest ice margin and drainage fluctuations rather than a constant retreat throughout the Holocene. Shelf sediment provenances are dominated by relatively homogenized Baffin Island inputs during the mid to late Holocene, but record a slightly offshore ice margin position from the late Pleistocene to the early Holocene.&lt;/p&gt;

scholarly journals The Phantom Satiation Hypothesis of Bariatric Surgery

2021 ◽  
Vol 15 ◽  
Author(s):  
Laurent Gautron
Keyword(s):  
Bariatric Surgery ◽  
Gastric Bypass ◽  
Weight Gain ◽  
Large Scale ◽  
Emotional Responses ◽  
Unexplained Pain ◽  
Brain Circuits ◽  
Phantom Limbs ◽  
New Hypothesis ◽  
Satiation Hypothesis

The excitation of vagal mechanoreceptors located in the stomach wall directly contributes to satiation. Thus, a loss of gastric innervation would normally be expected to result in abrogated satiation, hyperphagia, and unwanted weight gain. While Roux-en-Y-gastric bypass (RYGB) inevitably results in gastric denervation, paradoxically, bypassed subjects continue to experience satiation. Inspired by the literature in neurology on phantom limbs, I propose a new hypothesis in which damage to the stomach innervation during RYGB, including its vagal supply, leads to large-scale maladaptive changes in viscerosensory nerves and connected brain circuits. As a result, satiation may continue to arise, sometimes at exaggerated levels, even in subjects with a denervated or truncated stomach. The same maladaptive changes may also contribute to dysautonomia, unexplained pain, and new emotional responses to eating. I further revisit the metabolic benefits of bariatric surgery, with an emphasis on RYGB, in the light of this phantom satiation hypothesis.

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