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.

Fast ice characteristics, with special reference to the eastern Canadian Arctic

Polar Record ◽  
1975 ◽  
Vol 17 (110) ◽  
pp. 521-536 ◽  
Author(s):  
John D. Jacobs ◽  
Roger G. Barry ◽  
Ronald L. Weaver
Keyword(s):  
Sea Ice ◽  
Canadian Arctic ◽  
The United States ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
National Academy Of Sciences ◽  
Ice Dynamics ◽  
Pack Ice ◽  
Fast Ice ◽  
Eastern Canadian Arctic

Arctic sea ice is currently receiving increasing attention, both in relation to technological problems associated with resources development and shipping (Walker and Penney, 1973), and to basic research questions. The polar pack ice in the Beaufort Sea, for example, is the focus of the Arctic Ice Dynamics Joint Experiment (AIDJEX) (Untersteiner, 1974), while an analysis of physical links between the characteristics of polar surfaces and climate is to be the crux of the United States contribution to the Polar Experiment (POLEX) (Weller and Bierly, 1973; National Academy of Sciences, 1974). A general discussion of sea ice, with emphasis on pack ice, has been presented recently by Wittman and Burkhart (1973), but another aspect of the sea ice regime deserving separate attention, particularly in the light of Arctic offshore oil developments, is the landfast or fast ice, ie that part of the sea ice which remains attached to the shore (see “Sea ice terminology”). This paper attempts to provide a broad picture of fast ice characteristics in the context of our field experience in the eastern Canadian Arctic.

Cenozoic relative movements of Greenland and North America by closure of the North Atlantic – Arctic plate circuit

2021 ◽  
Author(s):  
Annabel Causer ◽  
Graeme Eagles ◽  
Lucía Pérez-Díaz ◽  
Jürgen Adam
Keyword(s):  
North America ◽  
Canadian Arctic ◽  
Seafloor Spreading ◽  
Magnetic Data ◽  
Labrador Sea ◽  
Eurasian Plate ◽  
Geological Evidence ◽  
Plate Motions ◽  
The North ◽  
Eastern Canadian Arctic

<p>Models of Cenozoic plate motions between Greenland and North America often use magnetic anomalies in the Labrador Sea and Baffin Bay regions. The crustal origin of some of the older magnetic signatures, (pre C24, Paleocene) is questioned, and these models often portray Paleogene motions inconsistent with geological data from Nares Strait region. We test for a connection between the (mis)interpretation of anomalies and inconsistencies between model predictions and geological evidence by constructing a regional model that is not based on magnetic data in the Labrador Sea region. We do this by closing the North America – Greenland – Eurasian plate circuit from the Paleocene to Eocene – Oligocene Boundary (C25 – C13). Our findings show seafloor spreading in the Labrador Sea initiated during Eocene, and not Paleocene, times. In turn, we argue that C24 and older isochrons in the Labrador Sea are not suitable as isochron markers for modelling plate motions. We further show that the previously noted counterclockwise rotation of Greenland, marking the beginning of plate convergence in the eastern Canadian Arctic, is not a result of changes in seafloor spreading direction, but instead of the initiation of seafloor spreading in the Labrador Sea. Our model shows ~160km of shortening in the Eastern Canadian Arctic.</p>

scholarly journals Learning Case Study of a Shallow-Water Model to Assess an Early-Warning System for Fast Alpine Muddy-Debris-Flow

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 750
Author(s):  
Antonio Pasculli ◽  
Jacopo Cinosi ◽  
Laura Turconi ◽  
Nicola Sciarra
Keyword(s):  
Debris Flow ◽  
Shallow Water ◽  
Early Warning ◽  
Debris Flows ◽  
Early Warning System ◽  
Warning System ◽  
Extreme Weather Events ◽  
Water Model ◽  
Computational Time ◽  
Processing Unit

The current climate change could lead to an intensification of extreme weather events, such as sudden floods and fast flowing debris flows. Accordingly, the availability of an early-warning device system, based on hydrological data and on both accurate and very fast running mathematical-numerical models, would be not only desirable, but also necessary in areas of particular hazard. To this purpose, the 2D Riemann–Godunov shallow-water approach, solved in parallel on a Graphical-Processing-Unit (GPU) (able to drastically reduce calculation time) and implemented with the RiverFlow2D code (version 2017), was selected as a possible tool to be applied within the Alpine contexts. Moreover, it was also necessary to identify a prototype of an actual rainfall monitoring network and an actual debris-flow event, beside the acquisition of an accurate numerical description of the topography. The Marderello’s basin (Alps, Turin, Italy), described by a 5 × 5 m Digital Terrain Model (DTM), equipped with five rain-gauges and one hydrometer and the muddy debris flow event that was monitored on 22 July 2016, were identified as a typical test case, well representative of mountain contexts and the phenomena under study. Several parametric analyses, also including selected infiltration modelling, were carried out in order to individuate the best numerical values fitting the measured data. Different rheological options, such as Coulomb-Turbulent-Yield and others, were tested. Moreover, some useful general suggestions, regarding the improvement of the adopted mathematical modelling, were acquired. The rapidity of the computational time due to the application of the GPU and the comparison between experimental data and numerical results, regarding both the arrival time and the height of the debris wave, clearly show that the selected approaches and methodology can be considered suitable and accurate tools to be included in an early-warning system, based at least on simple acoustic and/or light alarms that can allow rapid evacuation, for fast flowing debris flows.

Conodont paleontology and biostratigraphy of Ordovician carbonates and petroliferous carbonates on Southampton, Baffin, and Akpatok islands in the eastern Canadian Arctic

1989 ◽  
Vol 26 (10) ◽  
pp. 1880-1903 ◽  
Author(s):  
Alexander D. McCracken ◽  
Godfrey S. Nowlan
Keyword(s):  
Canadian Arctic ◽  
Bedding Plane ◽  
Baffin Island ◽  
Jordan River ◽  
Oil Shales ◽  
Age Range ◽  
Eastern Canadian Arctic

Carbonate and petroliferous carbonate units ("oil shales") on Southampton, Baffin, and Akpatok islands have yielded a total of 2277 conodonts, the more biostratigraphically useful of which indicate not all units are correlative. The Boas River "shale", the lower of the two petroliferous units on Southampton Island, overlies the Bad Cache Rapids Group and contains a diverse fauna, including elements of Amorphognathus ordovicicus Branson and Mehl. Previous reports have indicated the presence of Culumbodina penna Sweet, a species whose range only barely overlaps that of A. ordovicicus in the middle Maysvillian. Carbonate beds and bedding-plane surfaces of the higher Red Head Rapids Formation at Sixteen Mile Brook yielded A. ordovicicus faunas containing Aphelognathus cf. A. divergens Sweet. These beds are likely Richmondian, since A. divergens is known elsewhere only from Richmondian strata. A metasicula of "Glyptograptus" hudsoni Jackson, several natural conodont assemblages, and fused enigmatic coniform elements were also found at Sixteen Mile Brook.The petroliferous unit in unnamed strata at Amadjuak Lake on Baffin Island contains Belodina area Sweet, which is indicative of a late Edenian to early Maysvillian age. Conodonts from the petroliferous strata at Jordan River on Baffin Island suggest a Trentonian to early Maysvillian age. The conodonts recovered from unnamed strata on Akpatok Island are not very diagnostic but indicate an age range from Shermanian to Gamachian.

An early nineteenth century meteorological register from the eastern Canadian Arctic

Polar Record ◽  
1995 ◽  
Vol 31 (178) ◽  
pp. 335-342 ◽  
Author(s):  
Paul A. Kay
Keyword(s):  
Nineteenth Century ◽  
Canadian Arctic ◽  
The Arctic ◽  
Research Centre ◽  
Historical Reconstruction ◽  
Early Nineteenth Century ◽  
Northwest Passage ◽  
Time Periods ◽  
Modern Experience ◽  
Eastern Canadian Arctic

AbstractSignificant warming in the Arctic is anticipated for doubled-CO2 scenarios, but temperatures in the eastern Canadian Arctic have not yet exhibited that trend in the last few decades. The spatial juxtaposition of the winter station in 1822–1823 of William Edward Parry's Northwest Passage expedition with the modern Igloolik Research Centre of the Science Institute of the Northwest Territories affords an opportunity for historical reconstruction and comparison. Parry's data are internally consistent. The association of colder temperatures with westerly and northerly winds, and wanner temperatures with easterly and southerly winds, is statistically significant. Temperatures are not exactly comparable between the two time periods because of differences in instrumentation, exposure, and frequency of readings. Nevertheless, in 1822–1823, November and December appear to have been cold and January to March mild compared to modern experience. Anomalously, winds were more frequently northerly (and less frequently westerly) in the latter months than in recent observations. Parry recorded two warm episodes in mid-winter, but, overall, it appears that the winter of 1822–1823 was not outside the range of modern experience.

scholarly journals Rare earth elements in freshwater, marine, and terrestrial ecosystems in the eastern Canadian Arctic

2017 ◽  
Vol 19 (10) ◽  
pp. 1336-1345 ◽  
Author(s):  
Gwyneth Anne MacMillan ◽  
John Chételat ◽  
Joel P. Heath ◽  
Raymond Mickpegak ◽  
Marc Amyot
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Canadian Arctic ◽  
Terrestrial Ecosystems ◽  
Eastern Canadian Arctic

Rare earth elements show consistent bioaccumulation patterns yet limited biomagnification in remote northern ecosystems.

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