TY - JOUR
T1 - Post-glacial sediment dynamics in the Irish Sea and sediment wave morphology
T2 - Data-model comparisons
AU - Van Landeghem, Katrien J.J.
AU - Uehara, Katsuto
AU - Wheeler, Andrew J.
AU - Mitchell, Neil C.
AU - Scourse, James D.
N1 - Funding Information:
The authors thank the Marine Institute of Ireland, the ship's scientific parties and crew members for assistance with swath bathymetry data collection on-board the RV Celtic Voyager through the auspices of various EU-INTERREG projects. We thank Gerry Sutton, Viv Blyth-Skyrme, Peter Croker and Alan Judd who (on behalf of the Coastal and Marine Resources Centre, the Joint Nature Conservation Committee, the Petroleum Affairs Division and the Department for Business, Enterprise and Regulatory Reform respectively) made swath bathymetry data available for this study. We address our additional acknowledgments to the reviewers and editor for their comments and suggestions. James Scourse acknowledges a Royal Society-Leverhulme Trust Senior Research Fellowship.
PY - 2009/7/30
Y1 - 2009/7/30
N2 - The irregular seafloor of the narrow Irish Sea on the NW European Shelf has been documented over several decades. From recently collected swath bathymetry data, very large trochoidal, nearly symmetrical sediment waves are observed in many parts of the Irish Sea and appear similar to those described from other continental shelf seas in North America that were covered by glacigenic sediments during the Last Glacial Maximum. Swath multibeam and single beam bathymetry data, backscatter intensity, shallow seismic imagery, video footage and sediment cores from the Irish Sea high sediment waves have been integrated to identify their genesis with reference to present and past hydrodynamic variability. From cross-sectional profiles over asymmetrical sediment waves in the Irish Sea the direction of asymmetry is used to map residual bed stress directions and associated bedload transport paths. Irish Sea peak bed stress vectors were generated using a two-dimensional palaeo-tidal model for the NW European shelf seas and compare well with the observations. Tidally induced bed stresses are modelled to have increased between 7-10 ka BP, to be nearly symmetrical in magnitude and to have reversed in dominant direction on a millennial scale. These environmental conditions during the post-glacial marine transgression are suggested here to help comprehend the construction of the very large sediment waves, with local variations due to differences in sediment grain size, sediment supply, water depth and intensified currents due to seafloor slopes. Model parameterisation using an open ocean boundary with time-dependent tidal changes and the implementation of high-resolution bathymetric information will improve future models of small-scale bed shear stress patterns and improve the predictive value of such modelling efforts.
AB - The irregular seafloor of the narrow Irish Sea on the NW European Shelf has been documented over several decades. From recently collected swath bathymetry data, very large trochoidal, nearly symmetrical sediment waves are observed in many parts of the Irish Sea and appear similar to those described from other continental shelf seas in North America that were covered by glacigenic sediments during the Last Glacial Maximum. Swath multibeam and single beam bathymetry data, backscatter intensity, shallow seismic imagery, video footage and sediment cores from the Irish Sea high sediment waves have been integrated to identify their genesis with reference to present and past hydrodynamic variability. From cross-sectional profiles over asymmetrical sediment waves in the Irish Sea the direction of asymmetry is used to map residual bed stress directions and associated bedload transport paths. Irish Sea peak bed stress vectors were generated using a two-dimensional palaeo-tidal model for the NW European shelf seas and compare well with the observations. Tidally induced bed stresses are modelled to have increased between 7-10 ka BP, to be nearly symmetrical in magnitude and to have reversed in dominant direction on a millennial scale. These environmental conditions during the post-glacial marine transgression are suggested here to help comprehend the construction of the very large sediment waves, with local variations due to differences in sediment grain size, sediment supply, water depth and intensified currents due to seafloor slopes. Model parameterisation using an open ocean boundary with time-dependent tidal changes and the implementation of high-resolution bathymetric information will improve future models of small-scale bed shear stress patterns and improve the predictive value of such modelling efforts.
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U2 - 10.1016/j.csr.2009.05.014
DO - 10.1016/j.csr.2009.05.014
M3 - Article
AN - SCOPUS:67650960814
SN - 0278-4343
VL - 29
SP - 1723
EP - 1736
JO - Continental Shelf Research
JF - Continental Shelf Research
IS - 14
ER -