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

Campbell, D C; Mosher, D.

doi:10.1016/j.margeo.2015.10.005

Cited by 36 publications

(9 citation statements)

References 73 publications

(167 reference statements)

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“…1; Normandeau Fonnesu et al, 2020). We conclude that sedimentation is enhanced in the levee located downstream of the contour current, probably resulting in a channel migrating upstream of the contour current, as suggested for mixed systems in northern Mozambique (Fonnesu et al, 2020) and in Nova Scotia, Canada (Campbell and Mosher, 2016), and not migrating downstream of the contour current as suggested for the South China Sea (He et al, 2013) and the Congo Basin, central Africa (Gong et al, 2018).…”

Section: Discussion and Conclusion Comparison With Natural Mixed Turbsupporting

confidence: 54%

Channel-levee evolution in combined contour current–turbidity current flows from flume-tank experiments

Miramontes

Eggenhuisen

Jacinto

et al. 2020

Geology

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Turbidity currents and contour currents are common sedimentary and oceanographic processes in deep-marine settings that affect continental margins worldwide. Their simultaneous interaction can form asymmetric and unidirectionally migrating channels, which can lead to opposite interpretations of paleocontour current direction: channels migrating against the contour current or in the direction of the contour current. In this study, we performed three-dimensional flume-tank experiments of the synchronous interaction between contour currents and turbidity currents to understand the effect of these combined currents on channel architecture and evolution. Our results show that contour currents with a velocity of 10–19 cm s−1 can substantially deflect the direction of turbidity currents with a maximum velocity of 76–96 cm s−1, and modify the channel-levee system architecture. A lateral and nearly stationary front formed on the levee located upstream of the contour current, reduced overspill and thus restrained the development of a levee on this side of the channel. Sediment was preferentially carried out of the channel at the flank located downstream of the contour current. An increase in contour-current velocity resulted in an increase in channel-levee asymmetry, with the development of a wider levee and more abundant bedforms downstream of the contour current. This asymmetric deposition along the channel suggests that the direction of long-term migration of the channel form should go against the direction of the contour current due to levee growth downstream of the contour current, in agreement with one of the previously proposed conceptual models.

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Section: Discussion and Conclusion Comparison With Natural Mixed Turbsupporting

confidence: 54%

Channel-levee evolution in combined contour current–turbidity current flows from flume-tank experiments

Miramontes

Eggenhuisen

Jacinto

et al. 2020

Geology

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“…5). Absent consensus on distinguishing large drifts from small ones, this study defined large drifts as those covering a plan view area of >1,000 km 2 (for a single drift) as defined in Campbell and Mosher (2015) along the Nova Scotia margin. We adopted the classification schemes for various types of drift morphology from Tucholke (1986), Faugères et al (1999), Rebesco and Stow (2001), Rebesco (2005), and Rebesco et al (2014).…”

Section: Recognition Of Contourite Depositional Systemsmentioning

confidence: 99%

“…Although 2D multichannel seismic reflection profiles do not resolve whether or not these channels represent contourites, the early Oligocene marks the onset of significant deep-water circulation in the basin (Tucholke and Embley, 1984). Furthermore, homogenous and stratified seismic facies infilling SU5 channels could arise from winnowing and redistribution of sediments by bottom currents (e.g., Campbell and Mosher, 2015). The relative importance of this process remains uncertain however.…”

Section: Seismic Unitmentioning

confidence: 99%

Seismic stratigraphic framework and depositional history for Cretaceous and Cenozoic contourite depositional systems of the Mozambique Channel, SW Indian Ocean

et al. 2020

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This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

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“…At the surface, the warm Gulf Stream flows northeastward, driving the anticyclonic subtropical gyre. At depth, the NW Atlantic is characterized by the presence of two gyres, whose motion is directly linked to the northward flowing Gulf Stream and the southward flowing DWBC (Figure 1 and supporting information Figure S1) (Calvin Campbell & Mosher, 2016;Schmitz & McCartney, 1993). These gyres and currents respond to changing climatic conditions (Keffer et al, 1988;Keigwin et al, 1998;Lynch-Stieglitz et al, 1999) and exert a strong influence on the redistribution of sediments within the basin, even eroding the bottom seafloor if they are intense and deep enough.…”

Section: North Atlantic Circulationmentioning

confidence: 99%

Distinguishing Glacial AMOC and Interglacial Non‐AMOC Nd Isotopic Signals in the Deep Western Atlantic Over the Last 1 Myr

Jaume‐Seguí

Kim

Pena

et al. 2020

Paleoceanog and Paleoclimatol

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The global thermohaline circulation plays a major role in regulating global climate, driven by the formation of North Atlantic Deep Water (NADW). ODP Site 1063 on the Bermuda Rise, at the interface of NADW and Southern Ocean-sourced water, appears an ideal location to study the relationships between ocean circulation and climate. This study reports Nd isotope ratios at Site 1063 that extend tõ 1 Ma. The data show Nd isotope values during portions of interglacials that are much lower than modern NADW. However, interglacial Nd isotope values at Site 607, located within the core of NADW, off the abyssal seafloor in the North Atlantic, are consistently similar to modern NADW. In contrast to glacial values, we infer that interglacial Nd isotopes at Site 1063 are not representative of NADW and do not solely record water mass mixing. We conclude that the low Ndisotope ratios reflect regional particleseawater exchange as a consequence of input of freshly ground bedrock from the Canadian shield, which is eroded into the North Atlantic during major ice sheet retreats. The result is a deep, thin, and regionally constrained layer of seawater tagged with this anomalous low Nd isotope signature that is unrepresentative of the Atlantic Meridional Overturning Circulation (AMOC). We suggest that a benthic nepheloid layer, whose development is linked to the behavior of a deep-recirculating gyre system, regulated by the interaction between the Gulf Stream and the deep western boundary current, facilitates the periodic masking of the Nd isotope signature of the North Atlantic AMOC end-member in this region at these depths.

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

Cited by 36 publications

References 73 publications

Channel-levee evolution in combined contour current–turbidity current flows from flume-tank experiments

Channel-levee evolution in combined contour current–turbidity current flows from flume-tank experiments

Seismic stratigraphic framework and depositional history for Cretaceous and Cenozoic contourite depositional systems of the Mozambique Channel, SW Indian Ocean

Distinguishing Glacial AMOC and Interglacial Non‐AMOC Nd Isotopic Signals in the Deep Western Atlantic Over the Last 1 Myr

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