Late Quaternary Pollen Diagrams from the Canadian Arctic Barren Grounds at Pelly Lake, Northern Keewatin, N.W.T.

1970 ◽  
Vol 2 (1) ◽  
pp. 43 ◽  
Author(s):  
Harvey Nichols
Keyword(s):  
Late Quaternary ◽  
Canadian Arctic ◽  
Pollen Diagrams ◽  
Barren Grounds

Late Quaternary Pollen Records from the Kobuk and Noatak River Drainages, Northwestern Alaska

1988 ◽  
Vol 29 (3) ◽  
pp. 263-276 ◽  
Author(s):  
Patricia M. Anderson
Keyword(s):  
Picea Glauca ◽  
Regional Differences ◽  
Late Quaternary ◽  
Limited Effect ◽  
Local Expansion ◽  
Thermal Maximum ◽  
Pollen Diagrams ◽  
Northern Alaska ◽  
River Drainages ◽  
Pollen Records

Pollen diagrams from Joe and Niliq Lakes date to ca. 28,000 and 14,000 yr B.P., respectively. Mesic shurb tundra grew near Joe Lake ca. 28,000 to 26,000 yr B.P. with localPopuluspopulations prior to ca. 27,000 yr B.P. Shrub communities decreased as climate changed with the onset of Itkillik II glaciation (25,000 to 11,500 yr B.P.), and graminoid-dominated tundra characterized vegetation ca. 18,500 to 13,500 yr B.P. Herb tundra was replaced by shrubBetulatundra near both sites ca. 13,500 yr B.P. with local expansion ofPopulusca. 11,000 to 10,000 yr B.P. andAlnusca. 9000 yr B.P. MixedPicea glauca/P. marianawoodland was established near Joe Lake ca. 6000 yr B.P. These pollen records when combined with others from northern Alaska and northwestern Canada indicate (1) mesic tundra was more common in northwestern Alaska than in northeastern Alaska or northwestern Canada during the Duvanny Yar glacial interval (25,000 to 14,000 yr B.P.); (2) with deglaciation, shrubBetulaexpanded rapidly in northwestern Alaska but slowly in areas farther east; (3) an early postglacial thermal maximum occurred in northwestern Alaska but had only limited effect on vegetation; and (4) pollen patterns in northern Alaska and northwestern Canada suggest regional differences in late Quaternary climates.

scholarly journals Palaeoenvironmental Interpretation of Late Quaternary Marine Molluscan Assemblages, Canadian Arctic Archipelago

2002 ◽  
Vol 54 (3) ◽  
pp. 301-315 ◽  
Author(s):  
Sandra Gordillo ◽  
Alec E. Aitken
Keyword(s):  
Environmental Factors ◽  
Species Composition ◽  
Continental Shelf ◽  
Marine Sediments ◽  
High Latitude ◽  
Late Quaternary ◽  
Canadian Arctic ◽  
High Arctic ◽  
Canadian Arctic Archipelago ◽  
Preservation Potential

Abstract This study examines neonto- logical and palaeontological data pertaining to arctic marine molluscs with the goal of reconstructing the palaeoecology of Late Quaternary ca. 12-1 ka BP glaciomarine environments in the Canadian Arctic Archipelago. A total of 26 taxa that represent 15 bivalves and 11 gastropods were recorded in shell collections recovered from Prince of Wales, Somerset, Devon, Axel Heiberg and Ellesmere islands. In spite of taphonomic bias, the observed fossil faunas bear strong similarities to modern benthic molluscan faunas inhabiting high latitude continental shelf environments, reflecting the high preservation potential of molluscan taxa in Quaternary marine sediments. The dominance of an arctic-boreal fauna represented by Hiatella arctica, Mya truncata and Astarte borealis is the product of natural ecological conditions in high arctic glaciomarine environments. Environmental factors controlling the distribution and species composition of the Late Quaternary molluscan assemblages from this region are discussed.

Problems of inertia and threshold related to post-Glacial habitat changes

1965 ◽  
Vol 161 (984) ◽  
pp. 331-342 ◽  
Keyword(s):  
Late Quaternary ◽  
Great Distance ◽  
Radiocarbon Age ◽  
Habitat Changes ◽  
Pollen Zone ◽  
Relative Chronology ◽  
Pollen Diagrams ◽  
Circular Argument ◽  
History Of

Most of the major late-Quaternary vegetational changes deduced from the study of pollen diagrams have generally been supposed to have been brought about by climatic change. The assumption has also been made that widespread climatically controlled vegetational changes are likely to have been broadly synchronous (cf. for instance Godwin 1956, p. 57). Recently, however, it has become clear that differences of migration rate and the rates of pedogenesis should be given more attention; Faegri, in particular, has made this point very strongly with reference to the history of the Scandinavian flora (Faegri 1963). In addition, it is appropriate to note that Iversen (1960, p. 9) has questioned whether we can attach any climatic significance to the pollen zone transitions up to the beginning of the Atlantic period and whether they will prove to be synchronous over any great distance. Nevertheless, the assumption that the well-marked vegetational changes in a small area such as the British Isles are likely to have been synchronous has sufficed to allow the establishment of a useful relative chronology for archaeological and other purposes. While the radiocarbon age estimations so far obtained do not on the whole confute the assumptions, there are a number of exceptions (cf. Godwin 1960; Godwin & Willis 1959, 1962; McAulay & Watts 1961, etc.). For phytogeographical purposes, however, it is clearly to argue in a circle to use a chronology based on vegetational evidence; we must equally be on our guard against the circular argument in discussing the role of habitat changes in palaeoecology.

HEAT FLOW DETERMINATIONS IN THE CANADIAN ARCTIC ARCHIPELAGO

1965 ◽  
Vol 2 (2) ◽  
pp. 59-71 ◽  
Author(s):  
L. K. Law ◽  
W. S. B. Paterson ◽  
K. Whitham
Keyword(s):  
Heat Flow ◽  
Late Quaternary ◽  
Canadian Arctic ◽  
The Arctic ◽  
Northwestern Part ◽  
Thermal Probe ◽  
Portable Equipment ◽  
Weighted Mean ◽  
Near Surface ◽  
Made In

Three heat flow determinations a were made in M'Clure Strait between Prince Patrick and Banks Islands in the northwestern part of the Arctic Archipelago of Canada. The three stations lie within 55 km of a point some 130 km SSW. of Mould Bay, Prince Patrick Island, and yield a weighted mean heat flow of 0.84 ± 0.09 μcal cm−2 s−1, or 57% only of the worldwide continental average. The measurements were made from sea ice in water depths of some 430 m using a thermal probe and portable equipment carried in a fixed-wing aircraft.Instrumental limitations and errors are discussed, together with environmental factors. The uncertainties in interpreting this result as a truly subnormal equilibrium heat flow are outlined but it is concluded that the calculated systematic errors are unlikely to exceed 25%. Consequently in the absence of any known major perturbing effect, it must be concluded that the structure responsible for the suppression of vertical magnetic held variations at Mould Bay observatory does not extend 130 km to the south, is not produced by an anomalously high near-surface temperature, or is of late-Quaternary origin.

A landsystems approach to understanding the evolution of ice-cored topography and distribution of retrogressive thaw slumps, western Canadian Arctic

2020 ◽  
Author(s):  
Peter Morse ◽  
Stephen Wolfe ◽  
Steve Kokelj
Keyword(s):  
Late Quaternary ◽  
Canadian Arctic ◽  
Laurentide Ice Sheet ◽  
Glacial Ice ◽  
Basal Ice ◽  
Holocene Climatic Optimum ◽  
Glaciofluvial Deposits ◽  
Quaternary History ◽  
Retrogressive Thaw Slump ◽  
Marginal Region

<p>The landscape of the Tuktoyaktuk Coastlands, western Canadian Arctic is dominated by glacial and geocryological processes that have modified, imprinted and sculpted the surface, depositing surficial materials upon underlying bedrock. Climate warming continues in this region at a rate that is twice the global average, and retrogressive thaw slump (RTS) activity is increasing. Recently, RTS distribution was associated with glacial limits reached by the Laurentide Ice Sheet and corresponding morainal deposits, but RTS are common in other local terrain units. In this glacial-marginal region, permafrost existed pre-glacially, and non-glacial geomorphic processes occurred throughout the Late Quaternary. Superimposed on these conditions are the effects of thermokarst during the Holocene climatic optimum, followed by a period of cooling. Collectively, these processes and associated forms and deposits have contributed variously to preservation, development, or degradation of permafrost and ground ice. The multifaceted Late Quaternary history in this region has impeded understanding of the distributions of ice-cored topography and RTS. For example, rather than glaciogenic ice, the long reigning regional model for ice-cored topography is according to post-glacial development of intrasedimental segregation-intrusion ice. Toward better understanding the evolution of the whole landscape and the distribution of climate-sensitive terrain, we use a landsystems approach as a means to understand how the ice-cored topography developed where RTS form, through analysing the cryostratigraphy. To this end, we identify 6 RTS representing a suite of ice-cored topographic settings, including: (i) preserved basal glacial ice facies within clayey diamict that has been thrusted and folded by glacial push representing morainal deposits of the Sitidgi Stade; (ii) ice contact outwash sediments associated with the Sitidgi Stade, overlying a thermo-erosional contact with underlying basal glacial icy diamict of the Toker Point Stade; (iii) deformed basal glacial ice, eroded down by meltwater-deposited outwash sands some time between the Toker Point and Sitidgi Stades (could be ca. 12.9 kyr BP); (iv) massive, undeformed segregation-intrusion basal ice, likely formed subglacially by freezing of intrasedimental water in pre-existing Pleistocene sands into the base of the glacier, overlain by glacial diamicton;  (v) deformed basal ice facies of intermediate Toker Point – Sitidgi Stades, with an upper layer that may be supra-glacial melt-out till into which segregated ice formed; and (vi) segregation ice that formed as permafrost aggraded into glaciolacustrine clays deposited in proglacial or glacially dammed basins, that was subsequently eroded down by glaciofluvial outwash (Sitidgi Stade). To summarize, the distribution of RTS reflects primarily the distribution of icy basal glacial diamict preserved in moraines, but also basal ice and icy basal diamict that are preserved beneath glaciofluvial deposits, segregation ice in glaciolacustrine deposits, and massive segregation-intrusion ice in Pleistocene sands beneath a till plain.</p>

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