Climatic evolution of the eastern Canadian Arctic and Baffin Bay during the past three million years

The outer east coast of Baffin Island is characterized by a series of sedimentary forelands. These contain a variety of litho- and biofacies associated with glacial marine and marine deposition into sea levels higher than those of the present. These high relative sea levels were associated with glacial isostatic loading and unloading of the crust by the NE sector of the Laurentide Ice Sheet. On the basis of amino acid epimerization ratios, eleven chronologically distinct units are delimited. The youngest unit is less than or equal to 10 ka, but all others are at or beyond the limits of radiocarbon dating. Based on biostratigraphy and amino acid data, the oldest units exposed in the forelands may be Pliocene in age. Molluscs, Foraminifera, and the palynology of buried soils and organics, indicate that the vast bulk of the exposed sequences contain floras and faunas that represent environments warmer than those at present. An analysis of modern and fossil pollen spectra suggests a steady decrease in low arctic conditions throughout the Quaternary.

1977 ◽  
Vol 14 (12) ◽  
pp. 2824-2857 ◽  
Author(s):  
G. H. Miller ◽  
J. T. Andrews ◽  
S. K. Short

A study of the stratigraphic sequence (14C and amino acid age control), marine bivalve faunal changes, and palynology of buried soils and organic-rich sediment collected from the Clyde Foreland Formation in the extensive cliff sections of the Clyde foreland, eastern Baffin Island, N.W.T., suggests the following last interglacial – Foxe (last glaciation) glacial – present interglacial sequence.(1) Cape Christian Member (ca. 130 000 years BP?)Consists of the Sledgepointer till overlain by the Cape Christian marine sediments. In situ molluscan fauna, collected from the marine sediments, contain a moderately warm bivalve assemblage. A well-developed soil that formed on the marine sediments (Cape Christian soil) contains an interglacial pollen assemblage dominated by dwarf birch. U-series dates of > 115 000 and ca. 130 000 years BP on molluscs from the Cape Christian marine sediments suggest that they were deposited during the last interglaciation, here termed the Cape Christian Interglaciation. The development of a subarctic pollen assemblage in the Cape Christian soil has not been duplicated during the present interglaciation, suggesting higher summer temperatures and perhaps a duration well in excess of 10 000 years for the last interglaciation.(2) Kuvinilk MemberConsists of fossiliferous marine sediments, locally divided by the Clyde till into upper and lower units. The Clyde till was deposited by the earliest and most extensive advance of the Foxe (last) Glaciation. Kuvinilk marine sediments both under- and overlying the Clyde till contain the pecten Chlamys islandicus, indicating that the outlet glacier advanced into a subarctic marine environment. Amino acid ratios from in situ pelecypod shells abovę and below the Clyde till are not statistically different, but contrast markedly with ratios obtained from the same species in the Cape Christian Member. Organic horizons within the Kuvinilk marine sediments contain a relatively rich pollen assemblage, although 'absolute' counts are low.(3) Kogalu Member (> 35 00014C years BP)Sediments of the Kogalu Member unconformably overlie those of the Kuvinilk Member, but are of a similar character. The dominant sediments are marine in origin, but in places are divided into upper and lower units by the Ayr Lake till. Amino acid ratios from in situ shells above and below the Ayr Lake till are indistinguishable, but substantially less than those in the Kuvinilk Member, suggesting the two members are separated by a considerable time interval. Radiocarbon dates on shells in the Kogalu marine sediments range from 33 000 to 47 700 years BP, but these may be only minimum estimates. The sea transgressed to a maximum level 70–80 m asl, coincident with the glacial maximum. Subarctic marine fauna of interstadial–interglacial character occur within the Kogalu marine sediments.(4) Eglinton Member (10 000 years BP to present)A major unconformity exists between the Kogalu and Eglinton Members. Ravenscraig marine sediments were deposited during an early Holocene marine transgression–regression cycle; the oldest dates on these sediments are ca. 10 000 years BP. Locally a vegetation mat occurs at the base or within the Ravenscraig unit. Pollen from these beds is sparse, but indicates a terrestrial vegetation assemblage as diverse as that of today. There is no evidence that Laurentide Ice reached the foreland during the last 30 000 years. Eolian sands that overlie a soil developed on the marine sediments record a late Holocene climatic deterioration. Pollen in organic-rich sediments at the base of, and within, the eolian sands record a vegetation shift in response to climatic change.


2020 ◽  
Author(s):  
Nicolas Young ◽  
Jason Briner ◽  
Gifford Miller ◽  
Alia Lesnek ◽  
Sarah Crump ◽  
...  

<p>The early Holocene (11.7 ka to 8.2 ka) represents the most recent period when the Laurentide and Greenland ice sheets underwent large-scale recession. Moreover, this ice-sheet recession occurred under the backdrop of regional temperatures that were similar to or warmer than today, and comparable to those projected for the upcoming centuries. Reconstructing Laurentide and Greenland ice sheet behavior during the early Holocene, and elucidating the mechanisms dictating this behavior may serve as a partial analog for future Greenland ice-sheet change in a warming world. Here, we use 123 new <sup>10</sup>Be surface exposure ages from two sites on Baffin Island and southwestern Greenland that constrain the behavior of the Laurentide and Greenland ice sheets, and an independent alpine glacier during the early Holocene. On Baffin Island, sixty-one <sup>10</sup>Be ages reveal that advances and/or stillstands of the Laurentide Ice Sheet and an alpine glacier occurred in unison around 11.8 ka, 10.3 ka, and 9.2 ka. Sixty-two <sup>10</sup>Be ages from southwestern Greenland indicate that the GrIS margin experienced re-advances or stillstands around 11.6 ka, 10.4 ka, 9.1 ka, 8.1 ka, and 7.3 ka. Our results reveal that alpine glaciers and the Laurentide and Greenland ice sheets responded in unison to abrupt early Holocene climate perturbations in the Baffin Bay region. We suggest that during the warming climate of the early Holocene, freshening of the North Atlantic Ocean induced by a melting Laurentide Ice Sheet resulted in regional abrupt cooling and brief periods of ice-sheet stabilization superimposed on net glacier recession. These observations point to a negative feedback mechanism inherent to melting ice sheets in the Baffin Bay region that slows ice-sheet recession during intervals of otherwise rapid deglaciation.</p>


2021 ◽  
Author(s):  
Johanna Hingst ◽  
Claude Hillaire-Marcel ◽  
Friedrich Lucassen ◽  
Christoph Vogt ◽  
Emmanuel Okuma ◽  
...  

<p>The reconstruction of late glacial ice sheet fluctuations helps understanding and modelling the local glacio-isostatic adjustment as well as global eustatic changes. From this viewpoint, the large-scale spatial and temporal variations of the Fox Basin-Baffin Island ice dome (NE Laurentide Ice Sheet, Canada) have been well documented. However, high frequency Holocene fluctuations and final decay of it are still poorly documented. We have thus investigated the behaviour of one of its eastern outlet glaciers in the Clyde Inlet fjord, northeastern Baffin Island. The reconstruction of ice sheet margin fluctuation is based on the radiogenic isotope composition (Sr-Pb-Nd) and mineral assemblage of detrital sediments in two marine cores raised within and off the Clyde Inlet (GeoB22346-3, Clyde Inlet head; GeoB22357-3, adjacent continental shelf). Radiogenic isotope ratios and bulk mineral assemblages from such sites are imprints of bedrock erosion along the active ice margin, as well as along ice-streams and subglacial drainage patterns. They may thus be used for the reconstruction of spatial and temporal variations in meltwater discharge into Baffin Bay and of the position of the active margin fluctuations inland. The location of the two sediment cores also informs on the traceability of radiogenic isotope signals from proximal to more distal areas of sediment deposition. Changes in mineralogical and radiogenic isotope compositions at the proximal core site suggest ice margin and drainage fluctuations rather than a constant retreat throughout the Holocene. Shelf sediment provenances are dominated by relatively homogenized Baffin Island inputs during the mid to late Holocene, but record a slightly offshore ice margin position from the late Pleistocene to the early Holocene.</p>


1983 ◽  
Vol 31 ◽  
pp. 86-106
Author(s):  
R. W. Feyling-Hanssen ◽  
S. Funder ◽  
K. Strand Petersen

A new occurrence of Plio-Pleistocene marine fossiliferous sediments from Jameson Land, East Green­land, is described and named the Lodin Elv Formation. The sedimentary sequence consists of sorted sand and silt overlain by diamicton containing erratic boulders. Both units contain in situ molluscs and foraminiferal assemblages. The sediments occur as an erosional remnant of local distribution, covered by Holocene deltaic sand, and probably rest on Jurassic shale. The thickness is c. 40 metres. The formation is dated faunistically by its foraminiferal faunas, which are correlated with occurrences in the North Sea and on Baffin Island. The suggested age is supported by amino acid analyses of mollusc shells. The Lodin Elv Formation records the earliest known evidence of glaciation and arctic conditions in Greenland in post-Precambrian time.


1979 ◽  
Vol 16 (5) ◽  
pp. 977-983 ◽  
Author(s):  
Stephen H. Waits

A variety of bedrock weathering features—both modern and remnant—including surface grus, polygonal cracks, siliceous glaze, tors, weathering pits, and tafoni typify upland outcrops on the Cumberland Peninsula. Tor ridges are particularly prevalent and at lower elevations they show significant modification and streamlining by flowing ice. On summit areas at elevations above 750 m, however, remnant corestones are preserved in situ, suggesting selective preservation of upland surfaces. Bedrock structure and composition, topographic position, and intensity of process strongly influence tor development. Weathering pits are common on high level, open summit surfaces where weathering occurs in response to both climate and continued removal of derived debris. Pit enlargement through lateral undercutting has been favoured by accumulation of protective bottom residua, mechanical weathering, and the presence of exfoliation crusts. It is postulated that salt crystallization plays a role in outcrop microweathering under present upland arctic conditions.


2021 ◽  
Vol 9 (10) ◽  
pp. 1050
Author(s):  
Marat Eseev ◽  
Dmitry Makarov

Usually, loading and unloading of cargo ships takes place in ports that are equipped with the infrastructure necessary to carry out such operations. In the Arctic, often a helicopter is the only way to get the cargo to the right place. Finding the optimal geographic location for unloading a ship using helicopters is an important task. It is necessary to create a support system for making the right decisions in such situations. Mathematical modeling has been used to find the geographical location that ensures the most favorable and quickest delivery of cargo from a vessel to its destination, using a helicopter. A criterion has also been found in which the search for the optimum point is a more rational way of unloading the vessel compared to other discharge options. The maps of the economic benefits of loading and unloading operations in this model have been developed. Using the example of the developed model, it is shown that during the transportation of goods in Ob Bay, significant economic and temporary advantages can be obtained. The developed model can be extended to the case of cargo delivery not only in the Arctic conditions, but also where the transport infrastructure is insufficiently developed.


1972 ◽  
Vol 9 (3) ◽  
pp. 233-238 ◽  
Author(s):  
J. T. Andrews ◽  
J. D. Ives ◽  
G. K. Guennel ◽  
J. L. Wray

A thin, impure limestone was found in situ on Precambrian bedrock at latitude 70°36.6′ N and longitude 75°20′ W some 26 km northwest of the Barnes Ice Cap. The unit consists of undulating laminations composed of alternating fine- and coarse-grained sediment, which are interpreted as a series of algal mats or algal-laminated sediments. An analysis of enclosed palynomorphs indicates the presence of Ulmus, Taxodiutm, Liriodendron, Carpinus, and Engelhardtia plus other genera. On the basis of the microflora a Paleogene age is assigned to the unit. The climate at that time was warm-temperate and the environment suggested is a freshwater marsh or swamp. The outcrop is restricted to a single hill summit and its location suggests considerable Neogene geomorphological activity, primarily river-cutting associated with vertical movements along the western margin of the Davis Strait/Baffin Bay Tift.


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