The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

Jennings, Anne E.

doi:10.7202/032929ar

Cited by 70 publications

(41 citation statements)

References 55 publications

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“…In their updated inventory, Margold et al (2015) also used the International Bathymetric Chart of the Arctic Ocean (IBCAO: Jakobsson et al, 2000) and more detailed swath bathymetry data from the Canadian Arctic (ArcticNet, 2013) to identify several new ice streams and confirm others that were previously hypothesised based only on terrestrial evidence. These bathymetric data have also been complemented by sub-surface data obtained from seismic reflection surveys, allowing workers to identify multiple till units, grounding zone wedges and other glacial features buried in the marine sediments; and to investigate the architecture of large trough mouth fans that often lie distal to the major ice stream troughs (Jennings, 1993;Andrews et al, 1995b;Rashid and Piper, 2007;Li et al, 2011;Siegel et al, 2012;Batchelor et al, 2013a,b;.…”

Section: Historical Perspective On Ice Streams In the Lismentioning

confidence: 98%

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Margold

Stokes

Clark

2015

Earth-Science Reviews

219

222

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This paper presents a comprehensive review and synthesis of ice streams in the Laurentide Ice Sheet (LIS) based on a new mapping inventory that includes previously hypothesised ice streams and includes a concerted effort to search for others from across the entire ice sheet bed. The inventory includes 117 ice streams, which have been identified based on a variety of evidence including their bedform imprint, large-scale geomorphology/ topography, till properties, and ice rafted debris in ocean sediment records. Despite uncertainty in identifying ice streams in hard bedrock areas, it is unlikely that any major ice streams have been missed. During the Last Glacial Maximum, Laurentide ice streams formed a drainage pattern that bears close resemblance to the present day velocity patterns in modern ice sheets. Large ice streams had extensive onset zones and were fed by multiple tributaries and, where ice drained through regions of high relief, the spacing of ice streams shows a degree of spatial self-organisation which has hitherto not been recognised. Topography exerted a primary control on the location of ice streams, but there were large areas along the western and southern margin of the ice sheet where the bed was composed of weaker sedimentary bedrock, and where networks of ice streams switched direction repeatedly and probably over short time scales. As the ice sheet retreated onto its low relief interior, several ice streams show no correspondence with topography or underlying geology, perhaps facilitated by localised build-up of pressurised subglacial meltwater. They differed from most other ice stream tracks in having much lower length-to-width ratios and have no modern analogues. There have been very few attempts to date the initiation and cessation of ice streams, but it is clear that ice streams switched on and off during deglaciation, rather than maintaining the same trajectory as the ice margin retreated. We provide a first order estimate of changes in ice stream activity during deglaciation and show that around 30% of the margin was drained by ice streams at the LGM (similar to that for present day Antarctic ice sheets), but this decreases to 15% and 12% at 12 cal ka BP and 10 cal ka BP, respectively. The extent to which these changes in the ice stream drainage network represent a simple and predictable readjustment to a changing mass balance driven by climate, or internal ice dynamical feedbacks unrelated to climate (or both) is largely unknown and represents a key area for future work to address.

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Section: Historical Perspective On Ice Streams In the Lismentioning

confidence: 98%

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Margold

Stokes

Clark

2015

Earth-Science Reviews

219

222

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“…Cumberland Sound hosted one of the ice-shelves for the NE part of the LIS, and it is known to have been occupied by grounded glacial ice-sheet at least until the YD (Jennings, 1993). Erosion of Cretaceous black shale has resulted in the accumulation of dark-color sediments (Jennings, 1993).…”

Section: Timing Of Cumberland Sound Ice-shelf and Hudson Strait Icestmentioning

confidence: 99%

Fine scale sediment structure and geochemical signature between eastern and western North Atlantic during Heinrich events 1 and 2

Rashid

Saint‐Ange

Barber

et al. 2012

Quaternary Science Reviews

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a b s t r a c tHeinrich iceberg-rafting events 1 and 2 (H1 and H2) in the Labrador Sea are identified by their typical nepheloid-flow deposit sedimentary structure, high bulk carbonate, increase in iceberg-rafted detritus (IRD), and depletion of d18 O in the surface-dwelling foraminifer, Neogloboquadrina pachyderma (s). Hlayers in this region have sedimentological characteristics different than those in the North Atlantic, and are consist of IRD interspersed in pelagic sediments. High resolution 14 C-AMS dates allowed us to delineate the leads and lags in instability between different ice-streams of the former Laurentide icesheet (LIS). Our data suggest that the discharge from the Hudson Strait ice-stream was followed by Cumberland Sound ice-sheet during H1 and H2. New radiogenic isotopes from the ice-proximal and surficial sediments of the greater Hudson Strait region and Labrador Sea H0, H1 and H2 layers suggest that carbonate-rich layers were only derived from Hudson Strait, not Baffin Bay. Fine scale structure of H1 and H2 intervals in Labrador Sea slope cores is characterized by two lithic peaks dominated by detrital carbonate grains and a single peak in cores from the central Labrador Sea. A similar pattern in the structure of H1 and H2 is observed along the western European margin. These findings contrast with North Atlantic H1 and H2 intervals, which are characterized by a peak of carbonate-rich grains, followed by a peak of quartz and volcanic grains. This comparison with North Atlantic and western European margin cores leads us to suggest that the coupling or lack thereof, between the LIS and European ice-sheet, is related to the depositional processes occurring along the margins, as well as the distance from the sources and the ability of the oceanic currents to disperse icebergs. Any significant change in ice-sheet dynamics would be recorded close to the ice-sheet margin, while distal locations would only record extreme events. We hypothesize that the discordance between the findings reported in the literature is most likely similar to the difference between the upper slope/ deep Labrador sites and the Flemish Pass site described in this contribution but requires vigorous testing.Crown

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“…To the north, sedimentological studies and high-resolution AMS dating of marine sediment cores from the SE Baffin and Labrador shelves, and adjacent slopes, led to a reconsideration of LLGM ice extent in that region (Dyke et al, 2002). Jennings (1993), for example, concluded that Cumberland Sound was filled by an ice stream until ~11.5 ka (~10 14 C ka) which Kaplan (1999) suggested may have extended onto the continental shelf (see also Miller et al, 2002). In northern Labrador, Clark and Josenhans (1990) combined marine and terrestrial evidence to suggest that LGM ice was more extensive than previously mapped, with the ice limit extending onto the continental shelf.…”

Section: Extent and Thickness Of The Lis At Its Local Last Glacial Mamentioning

confidence: 99%

Deglaciation of the Laurentide Ice Sheet from the Last Glacial Maximum

Stokes

2017

CIG

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ABSTRACT. The last deglaciation of the Laurentide Ice Sheet (LIS) was associated with major reorganisations in the ocean-climate system and its retreat also represents a valuable analogue for understanding the rates and mechanisms of ice sheet collapse. This paper reviews the characteristics of the LIS at its Last GlacialMaximum (LGM) La deglaciación del inlandsis Lauréntide desde el Último Máximo Glaciar RESUMEN. La última deglaciación del inlandsis Lauréntide (LIS) estuvo relacionada con grandes reorganizaciones en el océano-clima y su retroceso representa un valioso ejemplo para comprender las tasas y mecanismos del colapso del inlandsis. Este artículo revisa las características del LIS en su Último Máximo Glaciar (LGM) y su consiguiente deglaciación, con especial énfasis en

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The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

Cited by 70 publications

References 55 publications

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Ice streams in the Laurentide Ice Sheet: Identification, characteristics and comparison to modern ice sheets

Fine scale sediment structure and geochemical signature between eastern and western North Atlantic during Heinrich events 1 and 2

Deglaciation of the Laurentide Ice Sheet from the Last Glacial Maximum

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