Maximum extent and late glacial decay of the Laurentide Ice Sheet on Cumberland Peninsula, Baffin Island

AbstractOriented assemblages of parallel ridges and elongated lakes are widespread on the coastal lowlands of northeast Eurasia and Arctic North America, in particular, in Alaska, Arctic Canada, and northeast Siberia. So far, only the oriented lakes have been of much scientific interest. They are believed to be formed by thermokarst in perennially frozen ice-rich sediments, while their orientation is accounted for either by impact of modern winds blowing at right angles to long axes of the lakes (when it concerns individual lakes), or by the influence of underlying bedrock structures (in the case of longitudinal and transverse alignment of lake clusters).En masseexamination of space images suggests that oriented lake-and-ridge assemblages, not the oriented lakes alone, occur in the Arctic. Hence any theory about their formation should account for the origin and orientation of the assemblages as a whole. The existing hypotheses appear inadequate for this end, so this paper proposes that the assemblages were initially created by glacial activity, that is, by ice sheets that drumlinized and tectonized their beds, as well as by sub- and proglacial meltwater, and then they were modified by thermokarst, solifluction, and aeolian processes. This assumption opens up an avenue by which all known features of oriented landforms in the Arctic can be explained. The paper suggests that the oriented landforms in Siberia and Alaska are largely signatures of a marine Arctic ice sheet that transgressed from the north, while the Baffin Island and Mackenzie Delta forms were created by the respective sectors of the Laurentide ice sheet. The oriented features discussed belong to the last Late Glacial through the Early Holocene.

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First recognition of a Laurentide Ice Stream : Robert Bell on Hudson Strait

Géographie physique et Quaternaire ◽

10.7202/038993ar ◽

2010 ◽

Vol 61 (2-3) ◽

pp. 211-215 ◽

Cited By ~ 3

Author(s):

Ian A. Brookes

Keyword(s):

Ice Sheet ◽

Late Glacial ◽

Laurentide Ice Sheet ◽

Hudson Bay ◽

Baffin Island ◽

Ice Streams ◽

West Antarctic Ice Sheet ◽

West Antarctic ◽

Ice Stream ◽

Late Wisconsinan

Abstract In papers published in 1895 and 1901, and in undated notes for a 1907 paper he did not deliver or publish, Robert Bell of the Geological Survey of Canada interpreted the pattern of glacial striae, stossing of rock knobs, and surficial sediment composition along the margins of Hudson Strait, between Labrador, Ungava Bay and Baffin Island, as evidence of what he called an ice-stream, a long river-like glacier, fed from Hudson Bay and Foxe Basin, that had moved eastward along the Strait during the Late Glacial period. This was the earliest mention of such a glaciological feature within the Laurentide Ice Sheet (LIS). It was not until ice-streams were recognized in the West Antarctic Ice Sheet in the 1970’s that Bell’s concept was revived in the next decade and subsequently, in recognition of several ice-streams within the Late Wisconsinan LIS.

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An ice-marginal δ18O record from Barnes Ice Cap, Baffin Island, Canada

Annals of Glaciology ◽

10.3189/172756402781817031 ◽

2002 ◽

Vol 35 ◽

pp. 145-149 ◽

Cited By ~ 21

Author(s):

Christian M. Zdanowicz ◽

David A. Fisher ◽

Ian Clark ◽

Denis Lacelle

Keyword(s):

Ice Sheet ◽

Ice Cores ◽

Late Glacial ◽

Laurentide Ice Sheet ◽

Baffin Island ◽

Last Glacial ◽

Ice Cap ◽

White Band ◽

Arctic Ice ◽

The Last Glacial

AbstractBarnes Ice Cap, Baffin Island, Canada, is a remnant of the Laurentide ice sheet that separated from it about 8500 years ago. Owing to recession of the ice cap during the Holocene, Pleistocene-age ice is now exposed along the margin in a distinctive bubble-rich white band. δ18O variations across the white ice resemble those in Canadian Arctic ice cores, suggesting that Barnes Ice Cap preserves a climatic record through the last glacial period, possibly reaching back into the previous (Sangamon) interglacial. the δ18O shift at the Wisconsin–Holocene transition (15‰) exceeds that in other Canadian and Greenland records and cannot be explained solely in climatic terms. A steady-state model reconstruction of the Laurentide ice sheet during the Last Glacial Maximum suggests that Late-glacial strata in Barnes Ice Cap originated high up (>2400ma.s.l.) and far “inland” on the ice sheet, along a ridge that extended between the ancestral Foxe and Keewatin ice domes.

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Late Deglaciation of the Central Labrador Coast and Its Implications for the Age of Glacial Lakes Naskaupi and McLean and for Prehistory

Quaternary Research ◽

10.1016/0033-5894(90)90042-j ◽

1990 ◽

Vol 34 (3) ◽

pp. 296-305 ◽

Cited By ~ 25

Author(s):

Peter U. Clark ◽

William W. Fitzhugh

Keyword(s):

Sea Level ◽

Ice Sheet ◽

Late Glacial ◽

Time Frame ◽

Laurentide Ice Sheet ◽

Glacial Lakes ◽

Central Coast ◽

Relative Sea Level ◽

Level Curves

AbstractThe age of the marine limit and associated deglaciation has been estimated from relative sea-level curves for the Hopedale and Nain areas of the central Labrador coast as approximately 7600 ± 200 and 8500 ± 200 yr ago, respectively. These ages indicate that the ice margin remained on the coast for up to 3000 yr longer than previously estimated. Because the central coast is due east of glacial lakes Naskaupi and McLean, the earliest the lakes could have formed was <8500 ± 200 yr ago, with their largest phases being fully established only after 7600 ± 200 yr ago. This suggests that the age of the lakes, and associated deglaciation of the central Labrador-Ungava region, is younger by at least 1500 yr than previously estimated. A late-glacial marine-based ice mass in Ungava Bay that dammed the lakes collapsed ca. 7000 yr ago. Within this time frame, therefore, the glacial lakes only existed for <500 yr. The persistence of the Laurentide Ice Sheet margin on the central Labrador coast until 7600 yr ago probably restricted the northward movement of early prehistoric people into northern Labrador.

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Configuration and Dynamics of the Laurentide Ice Sheet During the Late Wisconsin Maximum

Géographie physique et Quaternaire ◽

10.7202/032467ar ◽

2007 ◽

Vol 36 (1-2) ◽

pp. 5-14 ◽

Cited By ~ 60

Author(s):

Arthur S. Dyke ◽

Lynda A. Dredge ◽

Jean-Serge Vincent

Keyword(s):

Ice Sheet ◽

Gravity Anomalies ◽

Late Glacial ◽

Laurentide Ice Sheet ◽

Geological Evidence ◽

Original Proposal ◽

Field Evidence ◽

Free Air ◽

Free Air Gravity ◽

Basin Region

ABSTRACT Prior to 1943 the Laurentide Ice Sheet was considered to have three major domes centered in Keewatin, Labrador, and Patricia (TYRRELL, 1898 a, b; 1913). FLINT (1943) argued that these centres were of only local and temporary importance and favoured a single-domed ice sheet. Despite the lack of supporting geological evidence, and despite the proposition of a Foxe Dome in the interim (IVES and ANDREWS, 1963), the single-dome concept was not seriously challenged until the late 1970's and, in fact, is still strenuously supported (HUGHES era/., 1977 ; DENTON and HUGHES, 1981). This paper extends and modifies recent conclusions that the Laurentide Ice Sheet had more than one dome at the Late Wisconsin maximum. We propose a model incorporating five domes (M'Clintock, Foxe, Labrador, Hudson, and (?) Caribou) based on the position of ice divides, ice flow patterns, drift composition, late-glacial features, postglacial isostatic recovery and free-air gravity anomalies. Our Labrador and Hudson domes closely correspond to Tyrrell's Labradorean and Patrician ice sheets; our Caribou and M'Clintock domes together with the Franklin Ice Complex over the Queen Elizabeth Islands north of the Laurentide Ice Sheet, correspond to Tyrrell's original Keewatin Ice Sheet. The style of glaciation of the Foxe Basin region was not known to Tyrrell, but our reconstruction of the Foxe Dome is in close agreement with the original proposal of Ives and Andrews. Like Tyrrell, our reconstruction is based on field evidence obtained through extensive mapping; the single dome model continues to be unsupported by geological data.

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GIS analyses of ice-sheet erosional impacts on the exposed shield of Baffin Island, eastern Canadian Arctic

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2015-0063 ◽

2015 ◽

Vol 52 (11) ◽

pp. 966-979 ◽

Cited By ~ 1

Author(s):

Karin Ebert

Keyword(s):

Ice Sheet ◽

Canadian Arctic ◽

Laurentide Ice Sheet ◽

Baffin Island ◽

Glacial Erosion ◽

Ice Sheet Erosion ◽

The Impact ◽

Exposure Ages ◽

Eastern Canadian Arctic ◽

Sheet Erosion

The erosional impacts of former ice sheets on the low-relief bedrock surfaces of Northern Hemisphere shields are not well understood. This paper assesses the variable impacts of glacial erosion on a portion of Baffin Island, eastern Canadian Arctic, between 68° and 72°N and 66° and 80°W. This tilted shield block was covered repeatedly by the Laurentide Ice Sheet during the late Cenozoic. The impact of ice-sheet erosion is examined with GIS analyses using two geomorphic parameters: lake density and terrain ruggedness. The resulting patterns generally conform to published data from other remote sensing studies, geological observations, cosmogenic exposure ages, and the distribution of the chemical index of alteration for tills. Lake density and terrain ruggedness are thereby demonstrated to be useful quantitative indicators of variable ice-sheet erosional impacts across Baffin Island. Ice-sheet erosion was most effective in the lower western parts of the lowlands, in a west–east-oriented band at around 350–400 m a.s.l., and in fjord-onset zones in the uplifted eastern region. Above the 350–400 m a.s.l. band and between the fjord-onset zones, ice-sheet erosion was not sufficient to create extensive ice-roughened or streamlined bedrock surfaces. The exception — where lake density and terrain ruggedness indicate that ice-sheet erosion had a scouring effect all across the study area — was in an area from Foxe Basin to Home Bay with elevations <400 m a.s.l. These morphological contrasts link to former ice-sheet basal thermal regimes during the Pleistocene. The zone of low glacial erosion surrounding the cold-based Barnes Ice Cap probably represents the ice cap’s greater extent during successive Pleistocene cold stages. Inter-fjord plateaus with few ice-sheet bedforms remained cold-based throughout multiple Pleistocene glaciations. In contrast, zones of high lake density and high terrain ruggedness are a result of the repeated development of fast-flowing, erosive ice in warm-based zones beneath the Laurentide Ice Sheet. These zones are linked to greater ice thickness over western lowland Baffin Island. However, adjacent lowland surfaces with similar elevations of non-eroded, weakly eroded, and ice-scoured shield bedrock indicate that—even in areas of high lake density and terrain ruggedness—the total depth of ice sheet erosion did not exceed 50 m.

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Subglacially precipitated carbonates record geochemical interactions and pollen preservation at the base of the Laurentide Ice Sheet on central Baffin Island, eastern Canadian Arctic

Quaternary Research ◽

10.1016/j.yqres.2013.10.014 ◽

2014 ◽

Vol 81 (1) ◽

pp. 94-105 ◽

Cited By ~ 6

Author(s):

Kurt A. Refsnider ◽

Gifford H. Miller ◽

Marilyn L. Fogel ◽

Bianca Fréchette ◽

Roxane Bowden ◽

...

Keyword(s):

Chemical Weathering ◽

Ice Sheet ◽

The Arctic ◽

Laurentide Ice Sheet ◽

Geochemical Data ◽

Baffin Island ◽

Columnar Crystal ◽

Ice Cap ◽

Basal Ice ◽

Isotopic Analyses

AbstractThe mineralogy and isotopic compositions of subglacially precipitated carbonate crusts (SPCCs) provide information on conditions and processes beneath former glaciers and ice sheets. Here we describe SPCCs formed on gneissic bedrock at the bed of the Laurentide Ice Sheet (LIS) during the last glacial maximum on central Baffin Island. Geochemical data indicate that the Ca in the crusts was likely derived from the subglacial chemical weathering Ca-bearing minerals in the local bedrock. C and Sr isotopic analyses reveal that the C in the calcite was derived predominantly from older plant debris. The δ18O values of the SPCCs suggest that these crusts formed in isotopic equilibrium with basal ice LIS preserved in the Barnes Ice Cap (BIC). Columnar crystal fabric and the predominance of sparite over micrite in the SPCCs are indicative of carbonate precipitation under open-system conditions. However, the mean δ18O value of the calcite crusts is ~ 10‰ higher than those of primary LIS ice preserved in the BIC, demonstrating that SPCCs record the isotopic composition of only basal ice. Palynomorph assemblages preserved within the calcite and basal BIC ice include species last endemic to the Arctic in the early Tertiary. The source of these palynomorphs remains enigmatic.

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The probable extent of Classical Wisconsin ice in southern and central Alberta

Canadian Journal of Earth Sciences ◽

10.1139/e77-226 ◽

1977 ◽

Vol 14 (11) ◽

pp. 2614-2619 ◽

Cited By ~ 35

Author(s):

A. MacS. Stalker

Keyword(s):

Ice Sheet ◽

Rocky Mountain ◽

Laurentide Ice Sheet ◽

The South ◽

Ice Flow ◽

Canadian Prairies ◽

Maximum Extent ◽

The North ◽

Glacier Advance

The margin of a former Laurentide ice sheet is traced through southern and central Alberta, from the Saskatchewan border southeast of Medicine Hat to beyond Rocky Mountain House, southwest of Edmonton. This margin, which marks the limit of a significant glacier advance or readvance, is thought to represent the maximum extent of Laurentide ice on the Canadian prairies during Classical Wisconsin time. In the south this margin follows a well-developed hummocky moraine; in the north it is indicated mainly by a discordance in trend of ice-flow markings, a disruption of drainage, and a change in maturity of topography on either side.

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Palaeo-ice streams in the northern Keewatin sector of the Laurentide ice sheet

Annals of Glaciology ◽

10.3189/172756405781812925 ◽

2005 ◽

Vol 42 ◽

pp. 135-144 ◽

Cited By ~ 41

Author(s):

Hernán De Angelis ◽

Johan Kleman

Keyword(s):

Potential Role ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Baffin Island ◽

Ice Streams ◽

Relative Age ◽

Ice Stream ◽

Deep Interior ◽

Ice Sheet Dynamics ◽

Streaming Flow

AbstractEvidence for ice streams in the Laurentide ice sheet is widespread. In the region of northern Keewatin and the Boothia Peninsula, Nunavut, Canada, palaeo-ice streams have been recognized, but their location, size and potential role in ice-sheet dynamics are poorly constrained. Based on the interpretation of satellite imagery, we produce a palaeo-ice-stream map of this region. Glacial directional landforms, eskers and moraines were mapped and integrated into landform assemblages using a glacial geological inversion model. Palaeo-frozen bed areas were also identified. Relative age of the geomorphic swarms was assessed by cross-cutting relationships and radiocarbon ages where available. Using this information we obtained a glaciologically plausible picture of ice-stream evolution within the northernmost Laurentide ice sheet. On the M’Clintock Channel corridor, three generations of pure ice streams are found. On Baffin Island and the Gulf of Boothia, glaciation was dominated by frozen-bed zones located on high plateaus and ice streams running along the troughs, i.e. topographic ice streams. A massive convergent pattern at the head of Committee Bay drained ice from both the Keewatin and Foxe sectors and was probably one of the main deglaciation channels of the Laurentide ice sheet. Finally, our results indicate that streaming flow was present in the deep interior of the Laurentide ice sheet, as recently shown for the Greenland and Antarctic ice sheets.

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Tors, felsenmeer, and glaciation in northern Cumberland Peninsula, Baffin Island

Canadian Journal of Earth Sciences ◽

10.1139/e77-248 ◽

1977 ◽

Vol 14 (12) ◽

pp. 2817-2823 ◽

Cited By ~ 102

Author(s):

D. E. Sugden ◽

S. H. Watts

Keyword(s):

Case Studies ◽

Ice Sheet ◽

Laurentide Ice Sheet ◽

Baffin Island

On the basis of two case studies in eastern Baffin Island it is suggested that tors and felsenmeer have survived beneath the Laurentide ice sheet. These features, therefore, need not be diagnostic of areas that escaped glaciation. Rather, the existence of tors and felsenmeer may reflect situations where the overlying Laurentide ice sheet was cold-based.

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