Late glacial and post-glacial history and emergence of the Ottawa Islands, Hudson Bay, Northwest Territories: Evidence on the deglaciation of Hudson Bay

1969 ◽  
Vol 6 (5) ◽  
pp. 1263-1276 ◽  
Author(s):  
J. T. Andrews ◽  
G. Falconer
Keyword(s):  
Northwest Territories ◽  
Sea Level ◽  
Late Glacial ◽  
Hudson Bay ◽  
Baffin Island ◽  
Glacial History ◽  
The West ◽  
Radiocarbon Dates ◽  
Northeastern Part ◽  
Present Rate

The Ottawa Islands are in the northeastern part of Hudson Bay. Evidence from crossing striations suggests that the earliest recorded glacial movement was toward the northeast. With deglaciation of Hudson Strait and central Hudson Bay the ice movement shifted progressively in an anti-clockwise direction, with the final movement being toward the west–southwest. The islands were deglaciated between 7610 and 7250 radiocarbon years ago. The marine limit is 158 m above sea level. Deltaic deposits below the marine limit are grouped into sets that correlate with glacial advances in Labrador–Ungava and Baffin Island, and with palynological results from Keewatin, suggesting that they reflect climatically induced processes rather than a balance in eustatic–isostatic movements. Radiocarbon dates on marine molluscs enable postglacial uplift and emergence curves to be drawn, which agree closely with predicted curves. Rates of uplift were about 0.06 m yr−1 at 6500 yr B.P., whereas the present rate is about 0.008 m yr−1. The deglaciation of Hudson Bay was marked by the splitting of the ice sheet along the submarine deep that trends southward between Mansel and Coats islands toward the southwest coast of the bay.

Late glacial ice margins and deglacial chronology for southeastern Baffin Island and Hudson Strait, eastern Canadian Arctic

1992 ◽  
Vol 29 (5) ◽  
pp. 1000-1017 ◽  
Author(s):  
Jay A. Stravers ◽  
Gifford H. Miller ◽  
Darrell S. Kaufman
Keyword(s):  
Canadian Arctic ◽  
Late Glacial ◽  
Hudson Bay ◽  
Baffin Island ◽  
Radiocarbon Dates ◽  
Glacial Ice ◽  
Sea Levels ◽  
Molluscan Fauna ◽  
Rising Sea Levels ◽  
Eastern Canadian Arctic

Radiocarbon dates from marine piston cores and from onshore raised marine stratigraphic sections in the Hudson Strait region were used to reconstruct deglacial isochrons for 9900, 9500, 8800–8500, and 8000 BP. At the culmination of the Gold Cove readvance (9900 BP), Labrador–Ungava ice flowed northeastward across Hudson Strait and outer Frobisher Bay and stood for the last time on the Baffin Island continental shelf. Subsequent retreat by calving was rapid and profound, opening the entire Hudson Strait marine trough by 9500 BP. At this time, ice dispersal from Foxe Basin, Labrador–Ungava, and local ice on Meta Incognita Peninsula supported tidewater margins along much of the coastline, with the exception of northernmost Ungava Peninsula, where the ice margin stabilized onshore. This onshore margin remained in place throughout the Cockburn Substage while a major northeastward readvance of Ungava Bay ice (the Noble Inlet readvance from 8800 to 8500 BP) crossed outer Hudson Strait, grounding on the Hudson Strait sill and the south coast of Meta Incognita Peninsula. Sedimentation continued in an enclosed basin in western Hudson Strait, but marine circulation was prohibited by the ice dam, and upper water column salinities became too low to support a marine molluscan fauna. Ungava Bay ice was not thick enough to sustain flow across eastern Hudson Strait, and rising sea levels soon destroyed the Noble Inlet ice dam. By 8300 BP normal marine waters were circulating in eastern Hudson Strait, followed shortly thereafter (at 8100 BP) by the deglaciation of western Hudson Strait and Hudson Bay.

scholarly journals Late Quaternary Deglaciation, Glaciomarine Sedimentation and Glacioisostatic Recovery in the Rivière Nastapoka Area, Eastern Hudson Bay, Northern Québec

2005 ◽  
Vol 57 (1) ◽  
pp. 65-83 ◽  
Author(s):  
Patrick Lajeunesse ◽  
Michel Allard
Keyword(s):  
Sea Level ◽  
Late Quaternary ◽  
Phase 1 ◽  
Second Phase ◽  
Hudson Bay ◽  
Silty Clay ◽  
Paleoenvironmental Reconstruction ◽  
Relative Sea Level ◽  
Radiocarbon Dates ◽  
Fluvial Terraces

Abstract This study presents a paleoenvironmental reconstruction of deglaciation dynamics and chronology, glaciomarine and postglacial sedimentation, as well as glacioisostatic recovery in the Rivière Nastapoka area, eastern Hudson Bay. Results indicate that the retreat of Québec-Labrador ice was mainly controlled by topography and was marked by four phases. Radiocarbon dates indicate that deglaciation began about 8.3 ka cal. BP and was characterized by a stillstand of the ice margin in the Nastapoka Hills that lead to the deposition of a drift belt in a high relative sea-level (Phase 1). After this stabilisation, the ice margin retreated rapidly eastward in a region of low relief and deposited a drape of silty clay in a falling relative sea-level (Phase 2). A second phase of stabilization of the ice margin lasted until at least 7.2 ka cal.BP on the higher shield peneplaine east of the limit of the Tyrrell Sea (Phase 3). This lead to the deposition of a belt of glaciofluvial deltas in a lower relative sea-level. Following this stillstand, the eastward retreat and subsequent ablation of the ice in central Québec-Labrador generated meltwater that transported large volumes of glacial sediments by fluvial processes and downcutting of fluvial terraces in previously deposited glaciofluvial and marine sediments (Phase 4). Glacioisostatic rebound reached 0.07 m/yr during the early phase of deglaciation and decreased to 0.04 m/yr between 6 and 5 ka cal. BP and 0.016 m/yr in the last 1000 years.

Evidence for reversal of basin polarity during carbonate ramp development in the Mesoproterozoic Borden Basin, Baffin Island

2002 ◽  
Vol 39 (4) ◽  
pp. 519-538 ◽  
Author(s):  
Anne G Sherman ◽  
Noel P James ◽  
Guy M Narbonne
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Deep Water ◽  
Foreland Basin ◽  
Baffin Island ◽  
The West ◽  
Marked Contrast ◽  
Accommodation Space ◽  
Basement Faults ◽  
Coppermine River

Distribution of facies in the lower half of the Bylot Supergroup suggests overall westward deepening of the Mesoproterozoic Borden Basin. In marked contrast, the upper half of the succession records a reversal in the overall bathymetric trend, such that the eastern portion underwent relative deepening as the west experienced relative shallowing. Strata deposited during this reversal belong to the Victor Bay Formation, a ramp composed predominantly of limestone. Karsting of carbonate strata and development of an angular unconformity in the west contrast with back-stepping and drowning of the ramp in the east, followed by mantling by deep-water limestone, carbonaceous carbonate, and turbidites. Increased accommodation space during this time, via both tectonic subsidence and eustatic sea-level rise, led to a profusion of stromatolite pinnacle reefs and large biostromes. The reversal of basin polarity is best reconciled with development of a distal foreland basin superimposed on the Borden aulacogen. Crustal rethickening and uplift occurred along reactivated basement faults during an eastward-directed compressional event and could be related to thrusting of similar age and vergence in the Coppermine River Group of northwestern Canada.

XIX.—The Late-glacial History of the Highlands and Islands of Scotland

1955 ◽  
Vol 62 (3) ◽  
pp. 769-928 ◽  
Author(s):  
J. K. Charlesworth
Keyword(s):  
Late Glacial ◽  
Glacial Period ◽  
Glacial History ◽  
The West ◽  
Orkney Islands ◽  
Second Stage ◽  
Late Glacial Period ◽  
The North ◽  
Moray Firth ◽  
History Of

SynopsisFrom the abounding moraines, drainage features (fig. 21) and other marginal indications an attempt has been made to reconstruct the successive phases of the ice in its retreat into the corries of the Highlands and Islands (Pl. I). Two late-glacial stages are recognised. During the first, the Highland Glaciation, an ice-margin ran from the Orkney Islands across the mouth of the Moray Firth to the Buchan and out to sea north of Aberdeen. Twelve substages (A–L) of retreat, arbitrarily selected, have been traced through the country, except in the Moraineless West where they are unrepresented.At the maximum of the second stage, the Moraine Glaciation, the ice readvanced to the line stage M (beaded line in Pl. I). The retreat from this line, the inner boundary of the Moraineless West and of the 100-foot raised beach (Pl. I), is divided into nine substages (N–V), based upon a consideration of snowlines. Substage N corresponds to the 50-foot raised beach, substage P to an important readvance.The snowline throughout the late-glacial period ran in the west parallel with the meridians and rose eastwards. The disposition of the snowlines for stage M is given in fig. 22, p. 900.The distribution of the ice in the British Isles during the North British, Highland and Moraine Glaciations is represented in fig. 23, p. 923.

scholarly journals Contraction-expansion dynamics of reef species in response to sea-level changes

2021 ◽  
Author(s):  
Thierry B Hoareau ◽  
Petrus Pretorius
Keyword(s):  
Sea Level ◽  
Subsequent Development ◽  
Population Level ◽  
Marine Species ◽  
Late Glacial ◽  
Sea Level Changes ◽  
Radiocarbon Dates ◽  
Last Glacial ◽  
Sea Level Fluctuations ◽  
The Last Glacial

The contraction-expansion model (CEM) describes the dynamics of species that survived in refugia during the last glacial maximum (LGM) and expanded their range when environmental conditions slowly improved from the Late Glacial through to the Holocene. The CEM has been proposed to describe the dynamics of reef species in response to sea-level fluctuations from a range of disciplines, but genetic inferences rather suggest stable population sizes since the last glacial period. Here, we address this paradox by providing a new model of modern reef development, by assessing the effect of LGM bottlenecks using genetic simulations, and by using a survey of the literature on reef species to compile both estimates of times to expansion and applied rates of molecular evolution. Using previously published radiocarbon dates of core data, we propose a synthetic model for the dynamics of modern coral reefs in the Indo-Pacific region. This model describes both an initiation at 9.9 ka and subsequent development that confirms a strong influence of sea-level fluctuations on reef dynamics. Simulations based on mtDNA datasets showed that pre-LGM genetic signatures of expansion are lost. Recent literature shows that, although genetic expansions of tropical marine species are frequent (>95%), the onset of these expansions is old (median ~110 ka), which indicates that most populations have remained stable since before the LGM. These pre-LGM expansions are explained by the low mutation rates (1.66% changes/site/Myr) known to be inadequate to calibrate time at population level. Specific calibrations should help solve the paradox and generalise the CEM for reef species.

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

2010 ◽  
Vol 61 (2-3) ◽  
pp. 211-215 ◽  
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.

Postglacial emergence of Ungava Peninsula, and its relationship to glacial history

1993 ◽  
Vol 30 (8) ◽  
pp. 1676-1696 ◽  
Author(s):  
James Gray ◽  
Bernard Lauriol ◽  
Denis Bruneau ◽  
Jean Ricard
Keyword(s):  
Tide Gauge ◽  
High Tide ◽  
Ice Sheet ◽  
Late Glacial ◽  
Hudson Bay ◽  
Radiocarbon Dates ◽  
Glacial Ice ◽  
Marine Terraces ◽  
New Synthesis ◽  
Rapid Deceleration

A series of 178 radiocarbon dates, of late glacial and postglacial age, from raised marine terraces on the Hudson Strait, Hudson Bay, and Ungava Bay coasts, permit a new synthesis of deglaciation history, postglacial emergence, and glacio-isostatic recovery of the Ungava Peninsula. Marine limits show three local highs, related to centres of ice loading: east of Hudson Bay; southwest of Ungava Bay, and in western Hudson Strait. Eastward extension of the latter to Cap de Nouvelle-France is attributed to early deglaciation. Emergence curves are presented from sites in (1) Hudson Strait ice-free prior to 9 ka; (2) Hudson Strait; (3) Hudson Bay; and (4) Ungava Bay liberated by Ungava ice between 8 and 6 ka. A sigmoidal pattern for the first group, with slow initial emergence, contrasts markedly with a pattern of rapid deceleration of emergence for the other groups. These differences are attributed to variations in rates of ice sheet unloading, immediately after coastal deglaciation. A stable onshore ice margin kept the northeastern tip of Ungava isostatically depressed, from initial deglaciation until 7 ka, whereas other mainland coasts were only liberated by retreat of the ice margin during a final phase of rapid thinning of the continental ice sheet. Isobases on emergence since 6.5, 5, and 2 ka, derived from marine and glacial lake shoreline data, indicate maximum ice loading centres in eastern Hudson Bay and in central Quebec–Labrador, with an extension northwards towards Ungava Bay. An uplift rate of 14 mm/year since 2 ka for Inukjuak on the Hudson Bay coast is compatible with very high tide gauge values. A downward gradient of 6.5 ka isobases in a northeasterly direction from southeastern Ungava towards present sea level on southern Resolution Island at the mouth of Hudson Strait suggests that Ungava Bay, despite late occupation by glacial ice, was probably not a major loading centre.

Holocene sea levels, paleoceanography, and late glacial ice configuration near the Northumberland Strait, Maritime Provinces

1987 ◽  
Vol 24 (4) ◽  
pp. 668-675 ◽  
Author(s):  
David B. Scott ◽  
Franco S. Medioli ◽  
Ann A. L. Miller
Keyword(s):  
Sea Level ◽  
Atlantic Coast ◽  
Late Glacial ◽  
Bay Of Fundy ◽  
Maritime Provinces ◽  
Glacial Ice ◽  
Sea Levels ◽  
Ice Caps ◽  
Present Rate ◽  
Nova Scotian

Work on new cores from old core sites in Baie Verte, New Brunswick, led to the identification of submerged salt-marsh peats, reported earlier as freshwater ones. A comprehensive sea-level curve, between 9 and 15 m below present, is based on marsh foraminiferal assemblages. These data indicate that between 4500 and 5400 BP relative sea-level (RSL) rise was comparatively slow (about 10 cm/100 years); the rate increased dramatically between 4500 and 4000 BP (1 m/100 years) and decreased between 2000 and 4000 BP to its present rate of 15 cm/100 years. We suggest RSL was falling before 5400 BP and that the sequence in our deepest core is similar to some observed in the Bay of Fundy and Nova Scotian Atlantic coast where early RSL fall is documented. To account for this sea-level record and others nearby we suggest that the ice history here is complex, with three separate ice caps thinning towards this area in late glacial times.Earlier work also indicated a number of sediment sequences barren of benthonic foraminifera, suggesting a complex marine–freshwater history for the area. The study of new cores containing the same sequences indicates no barren zones but a simple transgressive sequence with a warm-water calcareous fauna followed by an agglutinated transitional estuarine foraminiferal fauna.

Palynology and age of the Scott Inlet inliers of Baffin Island (Northwest Territories)

1985 ◽  
Vol 22 (10) ◽  
pp. 1542-1545 ◽  
Author(s):  
Elliott Burden ◽  
David Holloway
Keyword(s):  
Northwest Territories ◽  
Sea Level ◽  
Baffin Island ◽  
Quaternary Deposits

Scott Inlet inliers, previously regarded as Cretaceous–Paleogene, are reinterpreted on the basis of palynomorphs as Quaternary deposits derived from the erosion and transport of nearby (probably offshore) Cretaceous strata during periods of high sea level.

The Melville Moraine: sea-level change and response of the western margin of the Foxe Ice Dome, Melville Peninsula, Northwest Territories

1990 ◽  
Vol 27 (9) ◽  
pp. 1215-1224 ◽  
Author(s):  
L. A. Dredge
Keyword(s):  
Sea Level ◽  
Climatic Factors ◽  
Outer Part ◽  
Baffin Island ◽  
Ice Flow ◽  
Radiocarbon Dates ◽  
Western Margin ◽  
Level Change ◽  
Emergence Patterns ◽  
Lowland Area

Marine-limit elevations and radiocarbon dates from Melville Peninsula suggest rapid deglaciation of Committee Bay about 9100 years ago when sea level was 235 m higher than present. During deglaciation, an extensive prominent moraine with both terrestrial and glaciomarine segments developed along the western margin of the Foxe Ice Dome. It developed between 8500 and 6500 years ago as glaciologic response to the opening of the bay. By the time ice had receded from the moraine, sea level had dropped to about 140 m. Garry Bay was not deglaciated until ice lay east of the Melville Moraine. Lithologic evidence and the persistence of ice in this lowland area suggest that the outer part of Garry Bay was the calving terminus of a major ice stream flowing westwards across the peninsula. Four well-controlled emergence curves, based on 37 radiocarbon dates, are presented. The Baker Bay and Brevoort curves depict disjunct emergence patterns in which the disjunction corresponds in time and elevation to the formation of the moraine; the other two cover only the last 7000 years and depict a normal exponential style of emergence. Differences in timing and amount of emergence in the curve from Fury and Hecla Strait are attributed to a late ice flow southwards from Baffin Island. The Melville Moraine is younger than the age initially proposed for the Cockburn moraine system, of which it forms a part. It formed as a glaciodynamic response to a shift from marine-based to terrestrially grounded ice margin, rather than to climatic factors.

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