scholarly journals Stratigraphy and Paleoecology of Quaternary Sediments Along Pasley River, Boothia Peninsula, Central Canadian Arctic

2007 ◽  
Vol 41 (3) ◽  
pp. 323-344 ◽  
Author(s):  
Arthur S. Dyke ◽  
John V. Matthews
Keyword(s):  
Organic Material ◽  
Canadian Arctic ◽  
Quaternary Sediments ◽  
Organic Detritus ◽  
Tertiary Sediment ◽  
Glacier Ice ◽  
Nearby Source ◽  
Glaciomarine Sediments ◽  
Insect Fossils ◽  
Marine Basins

ABSTRACT Quaternary sediments exposed along Pasley River consist of a lower marine deltaic sand overlain in succession by complexly interbedded tills and glaciomarine sediments (the lower glacigenic assemblage), by a mid-section fluvial gravel, by an upper marine deltaic sand, and by glaciomarine sediment and till (the upper glacigenic assemblage). The midsection fluvial gravels contain plant and insect fossils indicating a climate as warm as and perhaps warmer than present. The top of the gravel is more than 55 000 years old ; the unit is probably of Sangamonian age (>75 000 ka) and separates Wisconsinan from lllinoian glacial deposits. The deltaic sands that underlie both glacigenic assemblages indicate substantial crustal depression during glacial buildup episodes prior to arrival of ice at the site. This implies that the process of buildup was slow and involved glacier expansion into major marine basins. Glaciomarine beds of the lower glacigenic assemblage locally contain abundant detrital terrestrial organic material as well as marine molluscs. The terrestrial organic detritus, an unusual constituent of glaciomarine sediment, is thought to have been released into the sea from glacier ice. These terrestrial fossil asemblages exhibit compositional differences which vary with the sediment faciès and probably reflect taphonomic factors such as differential buoyancy of the fossils. The upper marine deltaic sands contain some "old " rebedded plant detritus and amber indicating a nearby source of Tertiary sediment, possibly equivalent in age to the Beaufort Formation. Other rebedded fossils from the upper deltaic unit may be the same age as the mid-section fluvial gravels.

scholarly journals Bacterial diversity and lipid biomarkers in sea ice and sinking particulate organic material during the melt season in the Canadian Arctic

Elem Sci Anth ◽  
2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Rémi Amiraux ◽  
Jean-François Rontani ◽  
Fabrice Armougom ◽  
Eléonore Frouin ◽  
Marcel Babin ◽  
...  
Keyword(s):  
Organic Matter ◽  
Sea Ice ◽  
Organic Material ◽  
Early Stage ◽  
Canadian Arctic ◽  
Carbon Fluxes ◽  
Enzymatic Activities ◽  
Ice Melt ◽  
Sinking Particles ◽  
Potential Biomarkers

The estimation of important carbon fluxes in a changing Arctic environment remains a challenge, one that could benefit from the development of biomarkers that distinguish between sympagic (ice-associated) and pelagic organic material. Products of 10S-DOX-like lipoxygenase and fatty acid cis-trans isomerase (CTI) activity of bacteria attached to sympagic particulate organic matter (POM) were proposed previously as potential biomarkers of the contribution of sympagic biota to carbon fluxes to the seafloor. To date, neither the bacteria involved in such enzymatic activities nor the detection of these potential biomarkers at their presumed source (i.e., sea ice) has been investigated. Here, we determined and compared the diversity of prokaryotic communities (based on operational taxonomic units) attached to sea ice POM and under-ice sinking particles during an early stage of ice melt (brine drainage) in Baffin Bay (Canadian Arctic). Based on a time series of biodiversity analyses and the quantification of lipid tracers of these two bacterial enzymatic activities, we suggest that CTI-active bacteria, exposed to hypersaline stress, are attached to algal POM just above bottom sea ice and released into the water column following brine drainage. In contrast, bacteria attached to sinking particles and exhibiting 10S-DOX-like lipoxygenase activity are suggested to come from the bottommost layer of sea ice, where they may play a role in the detoxification of algae-produce free fatty acids. These results provide a refined view of the potential use of products of CTI activity as specific biomarkers of sympagic organic matter.

scholarly journals Supplementary material to "Thermokarst lakes formed in buried glacier ice: Observations from Bylot Island, eastern Canadian Arctic"

2021 ◽  
Author(s):  
Stéphanie Coulombe ◽  
Daniel Fortier ◽  
Frédéric Bouchard ◽  
Michel Paquette ◽  
Denis Lacelle ◽  
...  
Keyword(s):  
Canadian Arctic ◽  
Thermokarst Lakes ◽  
Bylot Island ◽  
Glacier Ice ◽  
Supplementary Material ◽  
Eastern Canadian Arctic

scholarly journals Depositional Environments and History of Late Quaternary Sediments in Hudson Strait and Ungava Bay: Further Evidence from Seismic and Biostratigraphic Data

2007 ◽  
Vol 46 (3) ◽  
pp. 311-329 ◽  
Author(s):  
Brian MacLean ◽  
Gustav Vilks ◽  
Bhan Deonarine
Keyword(s):  
Late Quaternary ◽  
Depositional Environments ◽  
Quaternary Sediments ◽  
The South ◽  
Bay Area ◽  
South Central ◽  
History Of ◽  
Ams Dating ◽  
Seafloor Sediments ◽  
Glaciomarine Sediments

ABSTRACT Regional ship-borne investigations of seafloor sediments provide further information on late Quaternary depositional environments and history in the Hudson Strait-Ungava Bay region. Greatest sediment thicknesses, up to 130 m, occur in the large basin in eastern Hudson Strait and in the western Hudson Strait basin north of Charles Island. Significant deposits are also present in basins southwest of Charles Island, along the south central part of the Strait, and in the southern part of Ungava Bay. Glacial drift deposits are widespread, but glaciomarine and postglacial sediments mainly occur in the basinal areas, with glaciomarine sediments generally predominating. Glaciomarine sediments are laterally transitional to glacial drift in the south central part of the Strait, and at many other basin margins. AMS dating of the deepest shells found within three cores from the glaciomarine sequences in the Wakeham Bay-Baie Héricart region of south central Hudson Strait yielded ages of 8390 ± 70,8420 ± 80, and 8520 ± 80 BP. Sequences underlying the dated intervals may contain time equivalents of glaciomarine sediments 1000-2000 years older found onshore in the Deception Bay area by Gray, Bruneau, and others.

Isolation of vesicular–arbuscular mycorrhizal spores: a rapid method for the removal of organic detritus from wet-sieved soil samples

1982 ◽  
Vol 28 (3) ◽  
pp. 363-365 ◽  
Author(s):  
R. M. N. Kucey ◽  
R. G. L. McCready
Keyword(s):  
Specific Gravity ◽  
Organic Material ◽  
Discontinuous Solution ◽  
Arbuscular Mycorrhizal ◽  
Soil Samples ◽  
Organic Detritus ◽  
Organic Debris ◽  
Vesicular Arbuscular ◽  
Large Soil ◽  
Solution Gradient

A method for recovery of live vesicular–arbuscular mycorrhizal spores from large soil samples is presented. Spores, hyphal material, and other organic debris are isolated by wet sieving (> 63 μm) and further purified by flotation on 50% glycerol. The organic material is then suspended in Ringer's saline solution and the spores separated from other organic material by centrifuging (10 min at 75 × g) the mixture on a two-layer discontinuous solution gradient consisting of 50% glycerol (specific gravity 1.13 g/cm3) overlaid with 30% glycerol (specific gravity 1.08 g/cm3). The efficiency of recovery is 84 ± 3.4% of the spores present after the initial flotation.

scholarly journals Cosmogenic analysis of glacial terrains in the eastern Canadian Arctic: a test for inherited nuclides and the effectiveness of glacial erosion

1999 ◽  
Vol 28 ◽  
pp. 181-188 ◽  
Author(s):  
P. Thompson Davis ◽  
Paul R. Bierman ◽  
Kimberly A. Marsella ◽  
Marc W. Caffee ◽  
John R. Southon
Keyword(s):  
Erosion Rate ◽  
Crater Lake ◽  
Canadian Arctic ◽  
Cosmic Ray ◽  
Baffin Island ◽  
Glacial Erosion ◽  
Cosmogenic Nuclide ◽  
Upper Limits ◽  
Glacier Ice ◽  
Ice Retreat

AbstractTo determine the effectiveness of glacial erosion and the magnitude of cosmogenic nuclide inheritance from prior periods of cosmic-ray exposure, we measured the abundance of 10Be and 26Al in nine samples collected from bedrock, boulders and cobbles exposed by the retreat of Tumbling Glacier, Baffin Island, Canada. Most samples had nuclide concentrations so low that we were only able to set upper limits for nuclide abundance. Three boulders, two on a Neoglacial moraine of Tumbling Glacier that impounds Crater Lake and one on a roche moutonnée within the Neoglacial moraine loop, had nuclide abundances indicating no more than 900 yr of exposure at the surface. Three bedrock samples, striated by Tumbling Glacier and exposed by ice retreat within the last 20 yr, have similarly low nuclide abundances. One bedrock sample, covered by Tumbling Glacier ice for some part of the Holocene but not eroded, allows us to estimate crudely the duration of Neoglaciation at our sample site (about 5450 yr) and to provide a lower limit on the erosion rate of Tumbling Glacier (0.10 ± 0.03 mm a–1). We analyzed two cobbles collected from the tops of roches moutonnées at Crater Lake; one cobble had the equivalent of 3000 yr of exposure, the other < 900 yr.

Bryozoan-rich layers in surficial Labrador Slope sediments, eastern Canadian Arctic

2003 ◽  
Vol 40 (3) ◽  
pp. 337-350 ◽  
Author(s):  
F C Thomas ◽  
I A Hardy ◽  
H Rashid
Keyword(s):  
Shallow Water ◽  
Debris Flows ◽  
Canadian Arctic ◽  
Labrador Sea ◽  
Transport Mechanisms ◽  
Quaternary Sediments ◽  
Piston Core ◽  
Heinrich Events ◽  
Pack Ice ◽  
Eastern Canadian Arctic

Layers rich in remains of a shallow-water bryozoan species, Idmidronea atlantica, have been found in Quaternary sediments in a piston core taken from 1085 m water depth in the Labrador Sea (59.700270°N, 60.238370°W), tens of kilometres from the nearest possible source. These layers occur anomalously in pelagic–hemipelagic muds with abundant planktic and deep-water benthic foraminifera, and are thus not in sediments attributable to mud turbidite or debris flows. The bryozoan remains appear to be most common in intervals just below Heinrich events H1 and H2 (~14 500 and ~20 600 14C years BP, respectively). Two possible ice-related transport mechanisms are suggested to have been involved in the deposition of the bryozoan fragments. The first method involved the scouring action of loose pack ice and (or) bergs dislodging and mobilizing attached bryozoans in shallow water, where they could be subsequently entrained in currents and transported to deeper water. The second method may have occurred when attached colonies of these animals were frozen in place as winter ice formed in shallow water, to be carried out to deeper conditions while still encased in loose floes the subsequent spring–summer.

Major end moraines of Younger Dryas age on Wollaston Peninsula, Victoria Island, Canadian Arctic: implications for paleoclimate and for formation of hummocky moraine

2000 ◽  
Vol 37 (4) ◽  
pp. 601-619 ◽  
Author(s):  
Arthur S Dyke ◽  
James M Savelle
Keyword(s):  
North America ◽  
Water Depth ◽  
Canadian Arctic ◽  
Younger Dryas ◽  
Ice Cores ◽  
Glacier Mass Balance ◽  
Canadian Arctic Archipelago ◽  
Climatic Control ◽  
Glacier Ice ◽  
Victoria Island

Some of the most extensive and massive end moraines of Younger Dryas age (11–10 14C ka BP) yet recognized in North America occur on Wollaston Peninsula of Victoria Island. On the western part of the peninsula, numerous closely spaced end moraines formed in the interval starting 11 100 ± 100 radiocarbon years ago and ending about 10 500–10 200 years ago. Net recession was generally slow throughout and was punctuated by moraine-building and at least two readvances. Recession is mapped with a resolution that is approximately decadal. The moraines form an orderly, nested succession and are consistently associated with westward shedding of meltwater, which formed a sequence of marine-limit deltas. We lack firm, independent proxy-climate evidence needed to assess whether these moraines formed because of cold Younger Dryas climate, rather than because of controls such as topographic setting and water depth, but climatic control seems probable. The moraines evidently retain glacier ice cores, as do most similarly large moraines in the Canadian Arctic Archipelago and northern mainland. They formed along active ice margins when the glacier mass balance on average was only slightly negative. Future melting of ice cores would produce regional hummocky moraine and much basal meltout till more than 10 000 years after deglaciation. Some southern areas of hummocky moraine may have originated as ice-cored moraines formed by active ice margins rather than from extensive regional stagnation.

Coleoptera fossils: their potential value for dating and correlation of late Cenozoic sediments

1977 ◽  
Vol 14 (10) ◽  
pp. 2339-2347 ◽  
Author(s):  
John V. Matthews Jr.
Keyword(s):  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Fossil Plants ◽  
Late Cenozoic ◽  
Extinct Species ◽  
Extant Species ◽  
Late Tertiary ◽  
Climatic History ◽  
Cenozoic Sediments ◽  
Insect Fossils

Coleoptera (beetle) fossils play an important role in paleoecological research, but as yet have contributed little information bearing on dating and correlation. The reason for this is that most Quaternary fossils represent extant species, precluding the evolutionary approach to dating, while the rarity and poor preservation of Tertiary beetle fossils, many of which are from extinct species, seriously limit their application to stratigraphic studies.Tertiary beetle fossils recently discovered in Arctic Canada and Alaska are both well preserved and abundant. Most of them represent extinct species that are closely related to living forms, hence they have potential stratigraphic value. In one case treated herein comparison of fossils of an Alaskan Tertiary species with those of a related species from the Beaufort Formation on Meighen Island (Canadian Arctic Archipelago) implies that the latter sediments were deposited less than 5.7 Ma ago. However, this conclusion requires testing because it is at odds with the date on Meighen Island exposures reached by study of fossil plants. I submit that further study of the insect fossils from the Beaufort Formation and other late Tertiary sites will help resolve such problems of dating and correlation.Quaternary beetle fossils have stratigraphic value even though fragments of that age represent for the most part only existing species. For example, it has been shown that late Pleistocene fossils of stenothermal Coleoptera species can provide a sensitive record of climatic change, and thus such fossils may be used for site to site correlation in areas where climatic history is well documented. In exceptional cases beetle fossils appear to provide a more accurate basis for correlation than even fossil pollen.

Sign in / Sign up

Export Citation Format

Share Document