The influence of turbidity currents and contour currents on the distribution of deep‐water sediment waves offshore eastern Canada

Sedimentology ◽  
2019 ◽  
Vol 66 (5) ◽  
pp. 1746-1767 ◽  
Author(s):  
Alexandre Normandeau ◽  
D. Calvin Campbell ◽  
Matthieu J. B. Cartigny
Keyword(s):  
Deep Water ◽  
Turbidity Currents ◽  
Eastern Canada ◽  
Sediment Waves

Recurrence of turbidity currents on glaciated continental margins: A conceptual model from eastern Canada

2020 ◽  
Vol 90 (10) ◽  
pp. 1305-1321
Author(s):  
Alexandre Normandeau ◽  
D. Calvin Campbell
Keyword(s):  
Conceptual Model ◽  
Sea Level ◽  
Deep Water ◽  
Turbidity Current ◽  
Sediment Supply ◽  
Turbidity Currents ◽  
Continental Margins ◽  
Submarine Canyons ◽  
Eastern Canada ◽  
Current Activity

ABSTRACT Turbidity currents in submarine canyons transport large volumes of sediment and carbon to the deep sea and are known to present a major risk to submarine infrastructure. Understanding the origin, the triggers, the recurrence, and the timing of these events is important for predicting future events and mitigating their impact. Depending on the morphological and latitudinal setting of submarine canyons, different external controls will govern the recurrence of turbidity currents. Here, we assess the recurrence of turbidity currents in shelf-incising submarine canyons off eastern Canada in order to examine the effects of external forcings such as glacier retreat and sea level on the deep-water sedimentary record. We used multibeam bathymetry, sub-bottom profiles, and the analysis of turbidites in sediment cores to infer the triggers of turbidity currents over time and propose a conceptual model for the activity of turbidity currents during glacial retreat. The chronostratigraphy of turbidites shows that turbidity current activity in the glaciated The Gully submarine canyon (eastern Canada) was highest between 24 ka cal BP (LGM) and 17 ka cal BP, with > 100 turbidites per 1,000 yr, when the ice sheet was directly delivering sediment to submarine canyons. As the ice margin retreated, the dominant sediment supply switched to glaciofluvial and then to longshore drift, while RSL remained low. The recurrence of turbidity currents nonetheless decreased drastically to < 10 per 1000 yr during that time, pre-dating the rise in RSL. This timing suggests that the reduction of turbidity-current activity is closely linked to retreating glaciers rather than to sea-level rise, which occurred later. Following the retreat of the ice sheet, sea level rose progressively to drown the shallow banks on the continental shelf, and turbidity currents ceased being active after 13 ka cal BP. In the late Holocene, landslide and concomitant turbidity-current recurrence increased to 1 per 1,000 yrs, with at least four new events recorded in deep water. This study shows that glacial sediment supply and sea level controlled the type of sediment supply to the continental slope, which in turn controlled the triggers of turbidity currents over time and the flushing of sediment to the deep water. By comparing with other glaciated margins, we propose a conceptual model explaining the recurrence of turbidity currents, taking into account RSL change and the position of the ice margin relative to the shelf edge. This conceptual model can help predict turbidity-current activity and offshore geohazards on other ancient and modern glaciated continental margins.

Deep-water renewal by turbidity currents in the Sulu Sea

Nature ◽  
1990 ◽  
Vol 348 (6299) ◽  
pp. 320-322 ◽  
Author(s):  
Detlef Quadfasel ◽  
Hermann Kudrass ◽  
Andrea Frische
Keyword(s):  
Deep Water ◽  
Turbidity Currents ◽  
Water Renewal ◽  
Sulu Sea

scholarly journals Autogenic influence on the morphology of submarine fans: an approach from 3D physical modelling of turbidity currents

2017 ◽  
Vol 47 (3) ◽  
pp. 345-368
Author(s):  
Cristiano Fick ◽  
Rafael Manica ◽  
Elírio Ernestino Toldo Junior
Keyword(s):  
Deep Water ◽  
Physical Modelling ◽  
Sediment Concentration ◽  
Experimental Series ◽  
Turbidity Currents ◽  
Geometrical Parameters ◽  
Submarine Fans ◽  
Relative Standard ◽  
Length Width ◽  
Depositional Evolution

ABSTRACT: Autogenic controls have significant influence on deep-water fans and depositional lobes morphology. In this work, we aim to investigate autogenic controls on the topography and geometry of deep-water fans. The influence of the sediment concentration of turbidity currents on deep-water fans morphology was also investigated. From the repeatability of 3D physical modeling of turbidity currents, two series of ten experiments were made, one of high-density turbidity currents (HDTC) and another of low-density turbidity currents (LDTC). All other input parameters (discharge, sediment volumetric concentration and grain size median) were kept constant. Each deposit was analyzed from qualitative and quantitative approaches and statistical analysis. In each experimental series, the variability of the morphological parameters (length, width, L/W ratio, centroid, area, topography) of the simulated deep-water fans was observed. Depositional evolution of the HDTC fans was more complex, showing four evolutionary steps and characterized by the self-channelizing of the turbidity current, while LDTC fans neither present self-channelizing, nor evolutionary steps. High disparities on the geometrical parameters of the fans, as characterized by the elevated relative standard deviation, suggest that autogenic controls induced a stochastic morphological behaviour on the simulated fans of the two experimental series.

Introduction to special section: Seismic interpretation of contourites and deep-water sediment waves

2021 ◽  
Vol 9 (2) ◽  
pp. SBi-SBii
Author(s):  
Dallas B. Dunlap ◽  
Piotr Krzywiec ◽  
Christian Hübscher ◽  
Gabriel Tagliaro ◽  
F. Javier Hernandez Molina
Keyword(s):  
Deep Water ◽  
Special Section ◽  
Seismic Interpretation ◽  
Sediment Waves

Deep-Water, Large-Scale Sediment Waves Bounded by the Valencia Channel

2016 ◽  
pp. 299-305
Author(s):  
Araceli Muñoz ◽  
Elena Elvira ◽  
Patricia Jiménez ◽  
Juan Acosta ◽  
Laura Pascual
Keyword(s):  
Deep Water ◽  
Large Scale ◽  
Sediment Waves

Sedimentary processes in the Selvage sediment-wave field, NE Atlantic: new insights into the formation of sediment waves by turbidity currents

Sedimentology ◽  
2000 ◽  
Vol 47 (6) ◽  
pp. 1181-1197 ◽  
Author(s):  
Russell B. Wynn ◽  
Philip P. E. Weaver ◽  
Gemma Ercilla ◽  
Dorrik A. V. Stow ◽  
Douglas G. Masson
Keyword(s):  
Wave Field ◽  
Turbidity Currents ◽  
Ne Atlantic ◽  
Sedimentary Processes ◽  
Sediment Wave ◽  
Sediment Waves

Classification and characterisation of deep-water sediment waves

2002 ◽  
Vol 192 (1-3) ◽  
pp. 7-22 ◽  
Author(s):  
Russell B. Wynn ◽  
Dorrik A.V. Stow
Keyword(s):  
Deep Water ◽  
Sediment Waves

scholarly journals Sedimentation of deep-water turbidites in the SW part of the Pannonian Basin

2010 ◽  
Vol 61 (1) ◽  
pp. 55-69 ◽  
Author(s):  
Boris Vrbanac ◽  
Josipa Velić ◽  
Tomislav Malvić
Keyword(s):  
Deep Water ◽  
Pannonian Basin ◽  
Eastern Alps ◽  
Turbidity Currents ◽  
Main Stream ◽  
North West ◽  
Fine Grained ◽  
The North ◽  
Sandstone Body ◽  
West Part

Sedimentation of deep-water turbidites in the SW part of the Pannonian BasinThe Sava Depression and the Bjelovar Subdepression belong to the SW margin of the Pannonian Basin System, which was part of the Central Paratethys during the Pannonian period. Upper Pannonian deposits of the Ivanic-Grad Formation in the Sava Depression include several lithostratigraphic members such as Iva and Okoli Sandstone Member or their lateral equivalents, the Zagreb Member and Lipovac Marlstone Member. Their total thickness in the deepest part of the Sava Depression reaches up to 800 meters, while it is 100-200 meters in the margins of the depression. Deposits in the depression are composed of 4 facies. In the period of turbiditic activities these facies are primarily sedimented as different sandstone bodies. In the Bjelovar Subdepression, two lithostratigraphic members (lateral equivalent) were analysed, the Zagreb Member and Okoli Sandstone Member. The thickness of the Bjelovar Subdepression ranges from 50 meters along the S and SE margins to more than 350 meters along the E margin. Generally, detritus in the north-west part of the analysed area originated from a single source, the Eastern Alps, as demonstrated by sedimentological and physical properties, the geometry of the sandstone body and the fossil content. This clastic material was found to be dispersed throughout the elongated and relatively narrow Sava Depression and in the smaller Bjelovar Subdepression. Sedimentation primarily occurred in up to 200 meters water depth and was strongly influenced by the sub-aqueous paleorelief, which determined the direction of the flow of turbidity currents and sandstone body geometries. The main stream with medium- and fine-grained material was separated by two independent turbiditic flows from N-NW to the SE-E. Variability in the thickness of sandstone bodies is the result of differences in subsidence and cycles of progradation and retrogradation of turbidite fans.

scholarly journals Foraminiferal Distribution in the Central and Western Parts of the Late Pleistocene Champlain Sea Basin, Eastern Canada

2007 ◽  
Vol 43 (1) ◽  
pp. 3-26 ◽  
Author(s):  
Jean-Pierre Guilbault
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Bottom Water ◽  
Late Glacial ◽  
Clay Layer ◽  
Eastern Canada ◽  
Deep Waters ◽  
High Zone ◽  
Water Stratification ◽  
Late Wisconsinan

ABSTRACT Marine sediments from the late-glacial Champlain Sea have been sampled at 20 localities representing the deeper part of the basin, between Ottawa and the Rivière St-François, Québec. Foraminiferal assemblages have been extracted and a sequence of three deep water and two shallow water ecozones recognized. The lowermost zone (A) is characterized by Cassidulina reniforme, Islandiella helenae and I. norcrossi and represents a paleosalinity of 25 to 30%o. The overlying zone B is dominated by Elphidium excavatum. It represents salinities decreasing from 25 to as low as 10%o. The uppermost zone (C) contains only a sparse assemblage of a morphotype of E. excavatum. If suggests a paleosalinity of no more than 10%o. A mostly unfossiliferous silt and clay layer of variable thickness (post-C) occurs above zone C. It is probably lacustrine. Below zone A and above the Late Wisconsinan till there is a pre-A interval whose variable assemblages represent hyposaline environments east of Montréal, predominantly lacustrine conditions west of Montréal and alternating hyposaline/ lacustrine environments near and south of Montréal. Bottom water temperatures were probably "Arctic" (within a few degrees of 0°) from the pre-A interval up to zone B inclusively. The data from zone C are too poor to estimate temperatures. The shallow water zones indicate environments with high (zone EH) or low (zone EA) salinities but of shallower depths than the deep water zones. The existence of two sequences is interpreted as the result of (probably seasonal) water stratification. The data does not allow to determine the depth of the limit between the shallow and deep waters.

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