Glacial and post-glacial sedimentary processes in the Irish Rockall Trough from an integrated acoustic analysis of near-seabed sediments

Sacchetti, Fabio; Benetti, Sara; Quinn, Rory; Cofaigh, Colm Ó

doi:10.1007/s00367-012-0310-2

Cited by 11 publications

(23 citation statements)

References 88 publications

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“…The areas lie offshore the Irish and Scottish continental shelves. The third one, the contouritic Feni Drift, extends on the west margin of the Rockall Trough and up to the deepest part of the basin in the south 29,30 (Fig. 1).…”

Section: B Multiphase Failure In the Rockall Bank Ne Atlanticmentioning

confidence: 99%

“…Table I). The colour-scale indicates the thickness (m); the numbers on the deposits correspond to the thickness measurements (15,30,45, and 60 m). match with the estimations of the real landslide thickness from the seismic profiles, which is for both cases estimated at approximately 30 m. 35 Overall, it is noted that for good agreement of the simulated run-out lengths with the field observations the values of the input parameters have to be significantly low.…”

Section: B Landslide Scenariosmentioning

confidence: 99%

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Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

et al. 2018

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Section: B Multiphase Failure In the Rockall Bank Ne Atlanticmentioning

confidence: 99%

Section: B Landslide Scenariosmentioning

confidence: 99%

Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

et al. 2018

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“…The multibeam bathymetry was collected using a Simrad EM120 multibeam echo sounder with frequencies of 11.75-12.75 kHz. A detailed account on the processing of the multibeam data can be found in Sacchetti, Benetti, Quinn, et al (2012).…”

Section: Methodsmentioning

confidence: 99%

“…Bottom currents are responsible for the redistribution of sediments forming sediment drifts, most notably the Feni Drift that occupies the western side of the trough (Figure 1) and is mostly active during interglacial periods (Stoker, 1998;Stoker et al, 1998). Geochemistry, Geophysics, Geosystems Sacchetti, Benetti, Quinn, et al, 2012;Stoker et al, 1998). Shallow cores from the deeper basin floor contain coarse sandy turbidites and contourites alternating with hemipelagic layers .…”

Section: Regional Settingmentioning

confidence: 99%

On the timing and nature of the multiple phases of slope instability on eastern Rockall Bank, Northeast Atlantic

Georgiopoulou¹,

Krastel²,

Finch³

et al. 2018

Preprint

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One of the most challenging tasks when studying large submarine landslides is determining whether the landslide was initiated as a single large event, a chain of events closely spaced in time or multiple events separated by long periods of time as all have implications in risk assessments. In this study we combine new multichannel seismic profiles and new sediment cores with bathymetric data to test whether the Rockall Bank Slide Complex, offshore western Ireland, is the composite of multiple slope collapse events and, if so, to differentiate them. We conclude that there have been at least three voluminous episodes of slope collapse separated by long periods of slope stability, a fourth, less voluminous event, and possibly a fifth more localized event. The oldest event, Slide A (200 km 3 ), is estimated to be several hundred thousand years old. The second event, Slide B (125 km 3 ), took place at the same location as slide A, reactivating the same scar, nearly 200 ka ago, possibly through retrogression of the scarp. Slide C (400 km 3 ) took place 22 ka ago and occurred further north from the other slides. Slide D was a much smaller event that happened 10 ka ago, while the most recent event, albeit very small scale, took place within the last 1,000 years. This study highlights the need to thoroughly investigate large slide complexes to evaluate event sequencing, as seismic studies may hide multiple small-scale events. This work also reveals that the same slide scarps can be reactivated and generate slides with different flow behaviors.Plain Language Summary When studying large underwater landslides, determining whether what we see in our data was created by one large landslide event or several smaller events is very difficult due to the inaccessibility of the deep sea. But, being able to distinguish between different events and their frequency allows for more accurate risk assessments. Forty years ago, a large landslide was discovered in the northeast Atlantic, on the flank of an underwater plateau offshore of western Ireland. Studies since its discovery have interpreted it as one large event. With present-day technology and a higher resolution data set, we have discovered that it is composed of several landslides. The most recent, but very small and localized event, happened in the last 1,000 years. The one before is happened 10,000 years ago, and it was the size of 680,000 Olympic-size swimming pools. Around 22,000 years ago, a landslide 250 times bigger slid down the slope. Two more similar size events happened more than 200,000 years ago, but the further back in time we go the data resolution gets poorer. We think that the sizes of large underwater landslides found in the world's oceans and lakes may have been significantly overestimated, but their frequency may have actually been underestimated.

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“…2 bottom; Mayer et al, 1986). The combination of swath mapping and seismic reflection allows marine geologists to interpret how sediments have accumulated, allowing them to understand the long-term development of a marine sediment sequence (e.g., Sacchetti et al, 2013;Brothers et al, 2013).…”

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confidence: 99%

Deep-Sea Sediments

Lyle

2014

Encyclopedia of Marine Geosciences

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Glacial and post-glacial sedimentary processes in the Irish Rockall Trough from an integrated acoustic analysis of near-seabed sediments

Cited by 11 publications

References 88 publications

Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

Rheological considerations for the modelling of submarine sliding at Rockall Bank, NE Atlantic Ocean

On the timing and nature of the multiple phases of slope instability on eastern Rockall Bank, Northeast Atlantic

Deep-Sea Sediments

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