Late Quaternary history of contourite drifts and variations in Labrador Current flow, Flemish Pass, offshore eastern Canada

Marshall, Nicole R.; Piper, David J. W.; Saint‐Ange, Francky; Campbell, D C

doi:10.1007/s00367-014-0377-z

Cited by 26 publications

(10 citation statements)

References 40 publications

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“…Bottom waters may have been more stable through time, but there have surely been changes in near-surface productivity. Analysis of variability in Labrador Current strength, using grain-size variations from cores and sedimentation rates across a transect from Flemish Pass, provides evidence that the Labrador Current from at least 24 to 16 ka was relatively weaker and from 16 ka to present was stronger and increasing in strength (Marshall et al 2014 ). This increase in bottom current speed could explain the significant range expansion of geodiids following deglaciation in the northwestern Atlantic region observed in this study.…”

Section: Discussionmentioning

confidence: 99%

“…The surficial geology of the study area is a product of modern oceanographic processes and past glacial activity (e.g. Piper and Pereira 1992 ; Sonnichsen and King 2005 ; Marshall et al 2014 ; Weitzman et al 2014 ). The surficial geology is variable, but in general, in water depths less than 600 m, the shallow geology consists of glacial till with a veneer of sand and gravel up to several metres thick.…”

Section: Methodsmentioning

confidence: 99%

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Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic

et al. 2016

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Recent studies on deep-sea sponges have focused on mapping contemporary distributions while little work has been done to map historical distributions; historical distributions can provide valuable information on the time frame over which species have co-evolved and may provide insight into the reasons for their persistence or decline. Members of the sponge family Geodiidae are dominant members of deep-sea sponge assemblages in the northwestern Atlantic. They possess unique spicules called sterrasters, which undergo little transport in sediment and can therefore indicate the Geodiidae sponge historical presence when found in sediment cores. This study focuses on the slopes of Flemish Cap and Grand Bank, important fishing grounds off the coast of Newfoundland, Canada, in international waters. Sediment cores collected in 2009 and 2010 were visually inspected for sponge spicules. Cores containing spicules were sub-sampled and examined under a light microscope for the presence of sterrasters. These cores were also dated using X-radiographs and grouped into five time categories based on known sediment horizons, ranging from 17,000 years BP to the present. Chronological groupings identified Geodiidae sponges in four persistent sponge grounds. The oldest sterrasters were concentrated in the eastern region of the Flemish Cap and on the southeastern slope of the Grand Bank. Opportunistic sampling of a long core in the southeastern region of the Flemish Cap showed the continuous presence of sponge spicules to more than 130 ka BP. Our results indicate that the geodiids underwent a significant range expansion following deglaciation, and support a contemporary distribution that is not shaped by recent fishing activity.

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic

et al. 2016

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“…(2006) criticized this approach for the determination of fine particle sizes on the grounds that shape effects could lead to slow‐sinking platy particles below 10 μm in diameter leaking into the >10 μm range. However, such shape effects appear to be insignificant for glacial sediments from high latitude oceans because glacial grinding produces equant grains (Konert & Vandenberghe, 1997; N. Marshall et al., 2014). Overall, the reliability of laser sizer derived grain‐size data has been confirmed by recent studies (Li & Piper, 2015; Mao et al., 2018; N. Marshall et al., 2014; I. McCave and Andrews, 2019).…”

Section: Methodsmentioning

confidence: 99%

Evaluating Zr/Rb Ratio From XRF Scanning as an Indicator of Grain‐Size Variations of Glaciomarine Sediments in the Southern Ocean

Wilson

Wang

et al. 2020

Geochem Geophys Geosyst

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A range of techniques has been developed for fine sediment grain-size measurements, including Laser Particle Sizer, Sedigraph, and Coulter counter (Konert & Vandenberghe, 1997; I. McCave et al., 2006), enabling quantitative grain-size distribution data to be obtained. However, studies on marine sediment cores usually require analyses on large sample sets, such that an ability to obtain reliable sediment grain-size information more rapidly and conveniently would be of great interest to marine sedimentologists (e.g., D. Liu et al., 2019). Such a capability would open up the potential for targeting long high-resolution records, as well as improving spatial coverage, leading to new insights on past sediment transport and climate dynamics over a range of timescales. It is widely recognized that chemical elements can be preferentially enriched or depleted in specific grainsize fractions within sediments or sedimentary rocks, which is referred to as the "grain-size effect" (Bouchez et al., 2011; Jin et al., 2006; Yang et al., 2002). In most cases, this effect is considered unfavorable for geochemical data interpretation and needs to be excluded or corrected (

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“…However, the S̅S̅ data differ from those of the CaCO 3 (%), Ca/Ti, and δ 18 O data showing that the LC speeds were the strongest between 5 and 3.1 ka (Figure f) and thereafter gradually weakened to the present. Moreover, the late Holocene LC vigor was still stronger than that of the early Holocene [ Marshall et al , ]. Some variabilities in the S̅S̅ data over the last millennium may be a feature of climatic fluctuations in the Medieval Warm Period and Little Ice Age [ Sicre et al , ], but the temporal resolution and adequate dating control are insufficient to resolve these climate events.…”

Section: Discussionmentioning

confidence: 99%

The Holocene Labrador Current: Changing linkages to atmospheric and oceanographic forcing factors

et al. 2017

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The role of Labrador Current (LC) in providing freshwater to the North Atlantic and hence modulating the Atlantic meridional overturning circulation (AMOC) has been debated with very few data. This study provides the first data on the relative speed of the LC for the past 9.2 ka using mean size of the sortable silt of sediments as a proxy from a midshelf basin in the western Labrador Sea. LC speed progressively intensified from 9.2 to 5 ka, during which two meltwater events had minor influence. The LC was fastest between 5 ka and 3.1 ka and gradually weakened after 3.1 ka. The mean size of the sortable silt data shows overall covariations with similar existing data from deepwater areas of the greater North Atlantic, suggesting an overarching link that modulates changes in both the near‐surface and deep North Atlantic. A dynamical link between the LC and AMOC vigor is hypothesized in which high meltwater discharge in the Labrador Sea oriented the subpolar gyre (SPG) more north‐south (meridional), weakening the SPG and thus decelerating the upper limb of the AMOC. Conversely, reduction in LC transport during the late Holocene, due to the greater export of sea ice, oriented the SPG more east‐west.

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Late Quaternary history of contourite drifts and variations in Labrador Current flow, Flemish Pass, offshore eastern Canada

Cited by 26 publications

References 40 publications

Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic

Ancient deep-sea sponge grounds on the Flemish Cap and Grand Bank, northwest Atlantic

Evaluating Zr/Rb Ratio From XRF Scanning as an Indicator of Grain‐Size Variations of Glaciomarine Sediments in the Southern Ocean

The Holocene Labrador Current: Changing linkages to atmospheric and oceanographic forcing factors

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