S. Benetti | University of Ulster (original) (raw)
Papers by S. Benetti
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Marine Geology, 2012
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Marine Geology, 2009
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Geo-Marine Letters, 2013
ABSTRACT Near-seabed (<50 m) sediments were studied throughout the Irish sector of the... more ABSTRACT Near-seabed (<50 m) sediments were studied throughout the Irish sector of the Rockall Trough (ca. 123,000 km2) based on a combined analysis of shallow seismic (3.5 kHz) and multibeam swath data acquired by the Irish National Seabed Survey and reprocessed here at higher resolution. The detailed identification of seven acoustic facies served to classify the Rockall Trough into six main sedimentary provinces, incorporating the well-known Feni Drift, Donegal-Barra Fan and Rockall Bank mass flow. In the northern part of the study area, extensive mass transport deposits from both flanks of the trough are the dominant depositional features. Debris flow deposits formed by ice streaming of the British-Irish ice sheet characterise most of the Donegal-Barra Fan, whereas turbidite deposition occurs towards the toe of the fan. On the western margin of the trough, the post-glacial Rockall Bank mass flow deposit displays a rough topography with no acoustic penetration. Several failure scarps are visible on the flank of the bank where the mass flow originated, and pass downslope into large sediment lobes and smaller debris flow deposits. Smaller-scale mass transport deposits were also discovered close to some canyons indenting the eastern slope. High seismic penetration characterises the Feni contourite drift deposit, and precise mapping of its geographical extent shows that it is considerably wider than previously reported. The sediment waves that drape this drift are interpreted as predominantly relict features, and their varied geometry suggests a complex oceanographic regime. In the deeper part of the trough, the data reveal novel evidence of the widespread occurrence (about 12,000 km2) of distinct seismic and backscatter signatures indicating the possible presence of fluid escape structures within fine-grained sediments of mixed contouritic, hemipelagic and turbiditic origin. Sediment overloading and increased pore pressure resulting from extensive mass wasting to the north of the area is a likely cause of dewatering-rooted fluid migration towards the seabed, but further investigations are required to confirm the nature and origin of such fluids in the Rockall Trough.
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Journal of Maps, 2011
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Developments in Earth Surface Processes, 2011
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International Journal of Nautical Archaeology, 2011
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Quaternary Science Reviews, 2012
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Quaternary Science Reviews, 2010
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Marine Geology, 2008
A 330-km length of the little known continental shelf edge and slope of the Bellingshausen Sea, W... more A 330-km length of the little known continental shelf edge and slope of the Bellingshausen Sea, West Antarctica, is investigated using multibeam swath-bathymetric and sub-bottom profiler evidence. The shelf break is at 650–700 m across the 150-km wide Belgica Trough, and to either side is about 500 m. When full-glacial ice advanced across the shelf to reach the shelf break, it was
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Journal of Maps, 2010
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Journal of Maps, 2014
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This presentation will discuss the sedimentary processes that took place since the last glaciatio... more This presentation will discuss the sedimentary processes that took place since the last glaciation on the north-eastern margin of the Rockall Trough, offshore Ireland. With the use of seventeen sediment cores collected along the axes of two major canyons and across the northern Rockall Trough, changes in sedimentary processes from shelf edge to basin floor are revealed and examined. The aim is to better understand the sedimentary processes that occurred along the canyons and in the trough during the last glaciation, through the deglaciation and into the Holocene. On the basis of sedimentary structures, texture, grain size, X-radiograph character and physical properties thirteen depositional facies are recognised. These facies are interpreted in terms of depositional processes as: (1) Massive diamicton deposited as subglacial till on the continental shelf during the last glacial advance; (2) Fining upward gravels and sands, related to rise in sea level and changing of hydrographic co...
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During the last six years, the Geological Survey of Ireland and the Marine Institute of Ireland w... more During the last six years, the Geological Survey of Ireland and the Marine Institute of Ireland worked together on the multimillion Irish National Seabed Survey project with the purpose of mapping the Irish marine territory using a suite of remote sensing equipment, from multibeam to seismic, achieving 87% coverage of the marine zone. Ireland was the first country in the world to carry out an extensive mapping project of their extended Exclusive Economic Zone. The Irish National Seabed Survey is now succeeded by the multiyear INFOMAR Programme. INFOMAR will concentrate initially on mapping twenty-six selected priority bays, three sea areas and the fisheries-protection "Biologically Sensitive Area", and then will complete 100% mapping of the remainder of the EEZ. Designed to incorporate all elements of an integrated mapping programme, the key data acquisition will include hydrography, oceanographic, geological and heritage data. These data sets discharge Ireland's oblig...
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Bookmarks Related papers MentionsView impact
Marine Geology, 2012
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Journal of Maps
Multibeam echosounder data collected by the Irish National Seabed Survey (INSS) between 2000 and ... more Multibeam echosounder data collected by the Irish National Seabed Survey (INSS) between 2000 and 2001 in the Rockall Trough have been used by many projects to analyze the geomorphology and the sedimentary processes of the margins of the Trough. However, due to the low spatial resolution of 150-250 m and the amount of artefacts still embedded in the publicly available data, many geomorphological features have been overlooked. This paper shows that the same multibeam dataset can provide more detailed information on seabed processes when the latest hydrographic and backscatter post-processing techniques are used to reduce data artefacts and improve data quality and spatial resolution. The resulting map, presented here at a scale of 1:450,000, is based on a semi-automatic and manual interpretation of geomorphological features highlighted using a new and improved 30 m bathymetric grid and a multibeam backscatter mosaic obtained using the GEOCODER post-processing algorithm. Overall, the m...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Marine Geology, 2012
Bookmarks Related papers MentionsView impact
Marine Geology, 2009
Bookmarks Related papers MentionsView impact
Geo-Marine Letters, 2013
ABSTRACT Near-seabed (<50 m) sediments were studied throughout the Irish sector of the... more ABSTRACT Near-seabed (<50 m) sediments were studied throughout the Irish sector of the Rockall Trough (ca. 123,000 km2) based on a combined analysis of shallow seismic (3.5 kHz) and multibeam swath data acquired by the Irish National Seabed Survey and reprocessed here at higher resolution. The detailed identification of seven acoustic facies served to classify the Rockall Trough into six main sedimentary provinces, incorporating the well-known Feni Drift, Donegal-Barra Fan and Rockall Bank mass flow. In the northern part of the study area, extensive mass transport deposits from both flanks of the trough are the dominant depositional features. Debris flow deposits formed by ice streaming of the British-Irish ice sheet characterise most of the Donegal-Barra Fan, whereas turbidite deposition occurs towards the toe of the fan. On the western margin of the trough, the post-glacial Rockall Bank mass flow deposit displays a rough topography with no acoustic penetration. Several failure scarps are visible on the flank of the bank where the mass flow originated, and pass downslope into large sediment lobes and smaller debris flow deposits. Smaller-scale mass transport deposits were also discovered close to some canyons indenting the eastern slope. High seismic penetration characterises the Feni contourite drift deposit, and precise mapping of its geographical extent shows that it is considerably wider than previously reported. The sediment waves that drape this drift are interpreted as predominantly relict features, and their varied geometry suggests a complex oceanographic regime. In the deeper part of the trough, the data reveal novel evidence of the widespread occurrence (about 12,000 km2) of distinct seismic and backscatter signatures indicating the possible presence of fluid escape structures within fine-grained sediments of mixed contouritic, hemipelagic and turbiditic origin. Sediment overloading and increased pore pressure resulting from extensive mass wasting to the north of the area is a likely cause of dewatering-rooted fluid migration towards the seabed, but further investigations are required to confirm the nature and origin of such fluids in the Rockall Trough.
Bookmarks Related papers MentionsView impact
Journal of Maps, 2011
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Developments in Earth Surface Processes, 2011
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
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International Journal of Nautical Archaeology, 2011
Bookmarks Related papers MentionsView impact
Quaternary Science Reviews, 2012
Bookmarks Related papers MentionsView impact
Quaternary Science Reviews, 2010
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Marine Geology, 2008
A 330-km length of the little known continental shelf edge and slope of the Bellingshausen Sea, W... more A 330-km length of the little known continental shelf edge and slope of the Bellingshausen Sea, West Antarctica, is investigated using multibeam swath-bathymetric and sub-bottom profiler evidence. The shelf break is at 650–700 m across the 150-km wide Belgica Trough, and to either side is about 500 m. When full-glacial ice advanced across the shelf to reach the shelf break, it was
Bookmarks Related papers MentionsView impact
Journal of Maps, 2010
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Journal of Maps, 2014
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This presentation will discuss the sedimentary processes that took place since the last glaciatio... more This presentation will discuss the sedimentary processes that took place since the last glaciation on the north-eastern margin of the Rockall Trough, offshore Ireland. With the use of seventeen sediment cores collected along the axes of two major canyons and across the northern Rockall Trough, changes in sedimentary processes from shelf edge to basin floor are revealed and examined. The aim is to better understand the sedimentary processes that occurred along the canyons and in the trough during the last glaciation, through the deglaciation and into the Holocene. On the basis of sedimentary structures, texture, grain size, X-radiograph character and physical properties thirteen depositional facies are recognised. These facies are interpreted in terms of depositional processes as: (1) Massive diamicton deposited as subglacial till on the continental shelf during the last glacial advance; (2) Fining upward gravels and sands, related to rise in sea level and changing of hydrographic co...
Bookmarks Related papers MentionsView impact
During the last six years, the Geological Survey of Ireland and the Marine Institute of Ireland w... more During the last six years, the Geological Survey of Ireland and the Marine Institute of Ireland worked together on the multimillion Irish National Seabed Survey project with the purpose of mapping the Irish marine territory using a suite of remote sensing equipment, from multibeam to seismic, achieving 87% coverage of the marine zone. Ireland was the first country in the world to carry out an extensive mapping project of their extended Exclusive Economic Zone. The Irish National Seabed Survey is now succeeded by the multiyear INFOMAR Programme. INFOMAR will concentrate initially on mapping twenty-six selected priority bays, three sea areas and the fisheries-protection "Biologically Sensitive Area", and then will complete 100% mapping of the remainder of the EEZ. Designed to incorporate all elements of an integrated mapping programme, the key data acquisition will include hydrography, oceanographic, geological and heritage data. These data sets discharge Ireland's oblig...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Marine Geology, 2012
Bookmarks Related papers MentionsView impact
Journal of Maps
Multibeam echosounder data collected by the Irish National Seabed Survey (INSS) between 2000 and ... more Multibeam echosounder data collected by the Irish National Seabed Survey (INSS) between 2000 and 2001 in the Rockall Trough have been used by many projects to analyze the geomorphology and the sedimentary processes of the margins of the Trough. However, due to the low spatial resolution of 150-250 m and the amount of artefacts still embedded in the publicly available data, many geomorphological features have been overlooked. This paper shows that the same multibeam dataset can provide more detailed information on seabed processes when the latest hydrographic and backscatter post-processing techniques are used to reduce data artefacts and improve data quality and spatial resolution. The resulting map, presented here at a scale of 1:450,000, is based on a semi-automatic and manual interpretation of geomorphological features highlighted using a new and improved 30 m bathymetric grid and a multibeam backscatter mosaic obtained using the GEOCODER post-processing algorithm. Overall, the m...
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