scholarly journals Climatic, geomorphologic and hydrologic perturbations as drivers for mid- to late Holocene development of ice-wedge polygons in the western Canadian Arctic

2018 ◽  
Vol 29 (3) ◽  
pp. 164-181 ◽  
Author(s):  
J. Wolter ◽  
H. Lantuit ◽  
S. Wetterich ◽  
J. Rethemeyer ◽  
M. Fritz
Keyword(s):  
Late Holocene ◽  
Canadian Arctic ◽  
Ice Wedge

Late Holocene syngenetic ice-wedge polygons development, Bylot Island, Canadian Arctic Archipelago

2004 ◽  
Vol 41 (8) ◽  
pp. 997-1012 ◽  
Author(s):  
Daniel Fortier ◽  
Michel Allard
Keyword(s):  
Late Holocene ◽  
Canadian Arctic ◽  
Canadian Arctic Archipelago ◽  
Thermal Contraction ◽  
Current Configuration ◽  
Outwash Plain ◽  
Bylot Island ◽  
Ice Wedge ◽  
The Mean ◽  
Organic Sediments

The initial configuration of the syngenetic ice-wedge polygons that developed in the outwash plain of glacier C-79 after 6000 BP was modified by the accumulation of wind-blown and organic sediments that began after 3670 ± 110 BP. The late Holocene sedimentation led to an increase in the thermal contraction coefficient of the soil and the formation of third- and fourth-order contraction cracks, partially explaining the current configuration of the polygonal network. The upturning of the sedimentary strata bordering the ice wedges was associated with the summer thermal expansion and resulting internal creep of the soil. The mean annual soil displacement coefficient was in the order of 2.5–2.7 × 10–5 /°C at the thousand-year scale. The late Holocene sedimentary strata under the centre of the polygons were undisturbed, which will make it possible to use this sedimentary record in further studies to attempt paleoenvironmental reconstructions from cores.

scholarly journals Late Holocene ice-wedge polygon dynamics in northeastern Siberian coastal lowlands

2018 ◽  
Vol 50 (1) ◽  
pp. e1462595 ◽  
Author(s):  
Lutz Schirrmeister ◽  
Anatoly Bobrov ◽  
Elena Raschke ◽  
Ulrike Herzschuh ◽  
Jens Strauss ◽  
...  
Keyword(s):  
Late Holocene ◽  
Ice Wedge ◽  
Coastal Lowlands

scholarly journals Thermokarst lake development in syngenetic ice-wedge polygon terrain in the Eastern Canadian Arctic (Bylot Island, Nunavut)

2019 ◽  
Author(s):  
Frédéric Bouchard ◽  
Daniel Fortier ◽  
Michel Paquette ◽  
Vincent Boucher ◽  
Reinhard Pienitz ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Canadian Arctic ◽  
Climatic Conditions ◽  
Gradual Transition ◽  
Freshwater Environment ◽  
Cooling Period ◽  
Lake Development ◽  
Thermokarst Lake ◽  
Ice Wedge ◽  
Eastern Canadian Arctic

Abstract. Thermokarst lakes are widespread and diverse across permafrost regions and they are considered significant contributors to global greenhouse gas emissions. Paleoenvironmental reconstructions documenting the inception and development of these ecologically important water bodies are generally limited to Pleistocene-age permafrost deposits (Yedoma) of Siberia, Alaska, and the western Canadian Arctic. Here we present the gradual transition from syngenetic ice-wedge polygon terrains to a thermokarst lake in the Eastern Canadian Arctic. We combine geomorphological surveys with paleolimnological reconstructions from sediment cores in an effort to characterize local landscape evolution from terrestrial to freshwater environment. Located on an ice-rich and organic-rich polygonal terrace, the studied lake is now evolving through active thermokarst, as revealed by subsiding and eroding shores, and was likely created by water pooling within a pre-existing topographic depression. Organic sedimentation in the valley started during the mid-Holocene, as documented by the oldest organic debris found at the base of one sediment core and dated at 4.8 kyr BP. Local sedimentation dynamics were initially controlled by fluctuations in wind activity, local moisture and vegetation growth/accumulation, as shown by alternating loess (silt) and peat layers. Fossil diatom assemblages were likewise influenced by local hydro-climatic conditions and reflect a broad range of substrates available in the past (both terrestrial and aquatic). Such conditions likely prevailed until ~ 2000 BP, when peat accumulation stopped as water ponded the surface of degrading ice-wedge polygons, and the basin progressively developed into a thermokarst lake. Interestingly, this happened in the middle of the Neoglacial cooling period, likely under wetter-than-average conditions. Thereafter, the lake continued to develop as evidenced by the dominance of aquatic (both benthic and planktonic) diatom taxa in organic-rich lacustrine muds. Based on these interpretations, we present a four-stage conceptual model of thermokarst lake development during the late Holocene, including some potential future trajectories. Such a model could be applied to other formerly glaciated syngenetic permafrost landscapes.

Holocene History of the Bering Sea Bowhead Whale (Balaena Mysticetus) in Its Beaufort Sea Summer Grounds off Southwestern Victoria Island, Western Canadian Arctic

2001 ◽  
Vol 55 (3) ◽  
pp. 371-379 ◽  
Author(s):  
Arthur S. Dyke ◽  
James M. Savelle
Keyword(s):  
Bering Sea ◽  
Late Holocene ◽  
Canadian Arctic ◽  
Beaufort Sea ◽  
Bowhead Whale ◽  
Bering Strait ◽  
Range Limit ◽  
Summer Range ◽  
Victoria Island ◽  
The Bering Sea

AbstractThe fossil remains of 43 bowhead whales were mapped on the raised beaches of western Wollaston Peninsula, Victoria Island, Canadian Arctic, near the historic summer range limit of the Bering Sea stock in the Beaufort Sea. The elevations and radiocarbon ages of the remains demonstrate that the bowhead ranged commonly into the region following the submergence of Bering Strait at ca. 10,000 14C yr B.P. until ca. 8500 14C yr B.P. During the same interval, bowheads ranged widely from the Beaufort Sea to Baffin Bay. Subsequently, no whales reached Wollaston Peninsula until ca. 1500 14C yr B.P. Late Holocene populations evidently were small, or occupations were brief, in comparison to those of the early Holocene. Although the late Holocene recurrence may relate to the expansion of pioneering Thule whalers eastward from Alaska, there are few Thule sites and limited evidence of Thule whaling in the area surveyed to support this suggestion.

scholarly journals Thermokarst lake inception and development in syngenetic ice-wedge polygon terrain during a cooling climatic trend, Bylot Island (Nunavut), eastern Canadian Arctic

2020 ◽  
Vol 14 (8) ◽  
pp. 2607-2627
Author(s):  
Frédéric Bouchard ◽  
Daniel Fortier ◽  
Michel Paquette ◽  
Vincent Boucher ◽  
Reinhard Pienitz ◽  
...  
Keyword(s):  
Sediment Cores ◽  
Canadian Arctic ◽  
Climatic Conditions ◽  
Gradual Transition ◽  
Freshwater Environment ◽  
Climatic Trend ◽  
Cooling Period ◽  
Thermokarst Lake ◽  
Ice Wedge ◽  
Eastern Canadian Arctic

Abstract. Thermokarst lakes are widespread and diverse across permafrost regions, and they are considered significant contributors to global greenhouse gas emissions. Paleoenvironmental reconstructions documenting the inception and development of these ecologically important water bodies are generally limited to Pleistocene-age permafrost deposits of Siberia, Alaska, and the western Canadian Arctic. Here we present the gradual transition from syngenetic ice-wedge polygon terrain to a thermokarst lake in Holocene sediments of the eastern Canadian Arctic. We combine geomorphological surveys with paleolimnological reconstructions from sediment cores in an effort to characterize local landscape evolution from a terrestrial to freshwater environment. Located on an ice- and organic-rich polygonal terrace, the studied lake is now evolving through active thermokarst, as revealed by subsiding and eroding shores, and was likely created by water pooling within a pre-existing topographic depression. Organic sedimentation in the valley started during the mid-Holocene, as documented by the oldest organic debris found at the base of one sediment core and dated at 4.8 kyr BP. Local sedimentation dynamics were initially controlled by fluctuations in wind activity, local moisture, and vegetation growth and accumulation, as shown by alternating loess (silt) and peat layers. Fossil diatom assemblages were likewise influenced by local hydro-climatic conditions and reflect a broad range of substrates available in the past (both terrestrial and aquatic). Such conditions likely prevailed until ∼2000 BP, when peat accumulation stopped as water ponded the surface of degrading ice-wedge polygons, and the basin progressively developed into a thermokarst lake. Interestingly, this happened in the middle of the Neoglacial cooling period, likely under colder-than-present but wetter-than-average conditions. Thereafter, the lake continued to develop as evidenced by the dominance of aquatic (both benthic and planktonic) diatom taxa in organic-rich lacustrine muds. Based on these interpretations, we present a four-stage conceptual model of thermokarst lake development during the late Holocene, including some potential future trajectories. Such a model could be applied to other formerly glaciated syngenetic permafrost landscapes.

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