Evidence for slope instability and current-induced sediment transport, the RMSTitanic wreck search area, Newfoundland rise

Cochonat, Pierre; Ollier, G.; Michel, Jean-Louis

doi:10.1007/bf02431041

Cited by 21 publications

(10 citation statements)

References 14 publications

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“…1c) and reveals subtle bedforms interpreted to represent asymmetrical sediment waves on the erosion surface, as well as small arc-shaped bedforms that possibly represent submarine barchan bedforms. Barchan bedform dimensions in this study are within the range of those reported for submarine barchan dunes elsewhere (Todd, 2005;Kenyon et al, 2002, Daniell andHughes, 2007;Cochonat et al, 1989). In the Weymouth 3D dataset, T11 is a strong seismic reflection that clearly truncates underlying reflections and marks the top of a widespread sediment wave interval (Fig.…”

Section: Large Erosional Featuressupporting

confidence: 68%

“…Barchan bedforms form in sediment-starved conditions, where there is limited mobile sediment available. Most examples of submarine barchans in the literature are from areas where glaciomarine sediments are reworked and barchans typically consist of mud and sand overlying a sandy to gravelly lag (Cochonat et al, 1989;Todd, 2005). Kenyon et al (2002) describe deepwater barchans in the Gulf of Mexico, where glaciomarine sediments are absent, and postulate that the bedforms are composed of foraminiferal sands overlying a …”

Section: Sediment Wave and Small Drift Formationmentioning

confidence: 98%

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Geophysical evidence for widespread Cenozoic bottom current activity from the continental margin of Nova Scotia, Canada

Campbell

Mosher

2016

Marine Geology

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Section: Large Erosional Featuressupporting

confidence: 68%

Section: Sediment Wave and Small Drift Formationmentioning

confidence: 98%

Geophysical evidence for widespread Cenozoic bottom current activity from the continental margin of Nova Scotia, Canada

Campbell

Mosher

2016

Marine Geology

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“…For comparison, we include an example of gravel antidunes from a modern tropical river (Alexander and Fielding 1997). B ϭ Bear Creek Fan (Prior and Bornhold 1989); G ϭ Glacier Bay (Carlson et al 1992); L ϭ Laurentian Fan (Hughes Clarke et al 1990); N ϭ Navy Fan (Normark et al 1979); T ϭ Titanic wreck area (Cochonat et al 1989;Savoye et al 1990); V ϭ Var Fan (Malinverno et al 1988). Valencia channel features interpreted as antidunes from Morris et al (1998). ably a consequence of cycles of eustatic sea-level change and/or fluctuations in sediment supply-caliber from the source area.…”

Section: Extra-basinal Controls On Evolution Of Intrachannel Erosionamentioning

confidence: 95%

A New Type of Bedform Produced by Backfilling Processes in a Submarine Channel, Late Miocene, Tabernas-Sorbas Basin, SE Spain

Pickering¹,

Hodgson²,

Platzman³

et al. 2001

Journal of Sedimentary Research

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The Late Miocene ''Solitary Channel,'' Tabernas-Sorbas basin, SE Spain, has been interpreted as a submarine channel fed by sediment gravity flows from the east. In this paper, the channel is reinterpreted as a lower-slope erosional channel fed by sediment gravity flows from the west. The channel shows cobble/pebble lag deposits, including breccias, associated with erosional phases with substantial sediment bypass, and a later infill by episodes of inclined backstepping macroforms (the primary focus in this paper), mainly comprising sands, interpreted here for the first time as channel backfill deposits. These inclined sandy macroforms, typically 2-5 m in height and 30-40 m in length, are described in detail for the first time in this paper, and are interpreted as a new large-scale sedimentary structure. We observe that the seeding process for the inclined sandy macroforms appears to have been in the upstream depression immediately behind ridges on the surface directly overlying cohesive debris-flow deposits.The internal channel architecture is interpreted in terms of fluctuating relative base levels. A purely local tectonic explanation for the inclined sandy macroforms is discounted because within the bed bundles, dips are essentially constant across the intrachannel disconformities. We speculate that the most likely overall change in base level throughout the history of the channel was driven by regional tectonic change. The higher-frequency variations were probably a consequence of fluctuations in sediment supply/caliber from the source area and/or of cycles of eustatic or regional sea-level changes. The channel was abruptly overlain by about 200 m of marls and then a heterolithic sheet-like turbidite system typical of a confined basin-floor setting. This change in depositional style represents a response to a significant overall decrease in basin-floor gradient, in which there was a differential change in base level, shown by the coeval development of a major angular unconformity farther east (Sorbas area). The channel history is important for sequence-stratigraphic modeling because it demonstrates that a backstepping fill can be caused by an overall tectonic control on the accommodation space (initiation and abandonment). Higher-frequency source-area changes in sediment flux/caliber and/or eustatic sea level probably exert a strong influence on the detailed depositional architecture in the channel (multiple bypass-backfill events).

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“…Bottomcurrent activity is considered to be insignificant in the study area, with respect to the depositional geometries observed. The Labrador Current primarily affects the sea floor in less than 500 m Turbidite deposition, Southwest Grand Banks Slope 1389 water depths (Hill & Bowen, 1983) and the Western Boundary Undercurrent affects sea floor sediments in water depths greater than about 4000 m (Cochonat et al, 1989).…”

Section: Geological Settingmentioning

confidence: 99%

Turbidite deposition on the glacially influenced, canyon-dominated Southwest Grand Banks Slope, Canada

et al. 2010

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The deeply dissected Southwest Grand Banks Slope offshore the Grand Banks of Newfoundland was investigated using multiple data sets in order to determine how canyons and intercanyon ridges developed and what sedimentary processes acted on glacially influenced slopes. The canyons are a product of Quaternary ice‐related processes that operated along the margin, such as ice stream outwash and proglacial plume fallout. Three types of canyon are defined based on their dimensions, axial sedimentary processes and the location of the canyon head. There are canyons formed by glacial outwash with aggradational and erosional floors, and canyons formed on the slope by retrogressive failure. The steep, narrow intercanyon ridges that separate the canyons are composite morphological features formed by a complex history of sediment aggradation and degradation. Ridge aggradation occurred as a result of mid to late Quaternary background sedimentation (proglacial plume fallout and hemipelagic settling) and turbidite deposition. Intercanyon ridge degradation was caused mainly by sediment removal due to local slump failures and erosive sediment gravity flows. Levée‐like deposits are present as little as 15 km from the shelf break. At 30 km from the shelf, turbidity currents spilled over a 400 m high ridge and reconfined in a canyon formed by retrogressive failure, where a thalweg channel was developed. These observations imply that turbidity currents evolved rapidly in this slope‐proximal environment and attained flow depths of hundreds of metres over distances of a few tens of kilometres, suggesting turbulent subglacial outwash from tunnel valleys as the principal turbidity current‐generating mechanism.

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Evidence for slope instability and current-induced sediment transport, the RMSTitanic wreck search area, Newfoundland rise

Cited by 21 publications

References 14 publications

Geophysical evidence for widespread Cenozoic bottom current activity from the continental margin of Nova Scotia, Canada

Geophysical evidence for widespread Cenozoic bottom current activity from the continental margin of Nova Scotia, Canada

A New Type of Bedform Produced by Backfilling Processes in a Submarine Channel, Late Miocene, Tabernas-Sorbas Basin, SE Spain

Turbidite deposition on the glacially influenced, canyon-dominated Southwest Grand Banks Slope, Canada

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