High-resolution seismo-stratigraphy and sedimentological properties of late- and postglacial sediments in Lac Guillaume-Delisle Estuary and Nastapoka Sound, eastern Hudson Bay

2008 ◽  
Vol 45 (4) ◽  
pp. 427-441 ◽  
Author(s):  
Caroline Lavoie ◽  
Philip R. Hill ◽  
Michel Allard ◽  
Guillaume St-Onge ◽  
Patrick Lajeunesse
Keyword(s):  
Late Quaternary ◽  
Sedimentary Basins ◽  
Distribution Patterns ◽  
Laurentide Ice Sheet ◽  
Eastern Coast ◽  
Hudson Bay ◽  
Mass Wasting ◽  
Stratigraphic Sequence ◽  
Acoustic Basement ◽  
Carbon Isotopic

Lac Guillaume-Delisle Estuary and Nastapoka Sound are two sedimentary basins that recorded the late Quaternary deglaciation on the eastern coast of Hudson Bay. Acoustic profiles reveal an average sediments thickness of 15 m in the estuary and 6 m in the sound. These sediments reach 70 m thick in deep glacial troughs. Within the studied basins, four seismo-stratigraphic units overlying the acoustic basement were recognized. Unit 1 (subaqueous ice-contact and draped glaciomarine deposits associated with the Quebec–Labrador Ice Sector (QLIS) of the Laurentide Ice Sheet (LIS) and the Tyrrell Sea) records the presence of a short ice-marginal stillstand during glacial retreat. Unit 2 (paraglacial and postglacial fluvial-deltaic deposits) and unit 3 (postglacial silty deposits) result from erosion of emerged sediments and redeposition in response to changes in relative sea level (RSL). Finally, unit 4 is composed of deformed deposits associated with a mass wasting event. The stratigraphic sequence and the spatial distribution patterns of deposits show that Lac Guillaume-Delisle is a good model to explain the dynamics of the QLIS margin during and after successive ice stillstands, continuous RSL fall, river discharge (ablation on land), and its final ablation inland. Additionally, seven cores were sampled in the southeast part of the estuary. Geochemical (organic carbon and total nitrogen) and carbon isotopic contents, used as alternative proxy, indicate that the sampled sediments correspond to the postglacial estuarine deposits of unit 3. Allochthonous sources of carbon dominate the supply to the sediments where the environment is regularly flushed by fresh and marine waters.

Stratigraphy, paleoecology, and glacial history of the Gillam area, Manitoba

1986 ◽  
Vol 23 (11) ◽  
pp. 1641-1661 ◽  
Author(s):  
Erik Nielsen ◽  
Alan V. Morgan ◽  
Anne Morgan ◽  
R. J. Mott ◽  
N. W. Rutter ◽  
...  
Keyword(s):  
Aspartic Acid ◽  
Late Quaternary ◽  
River Sediments ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Mass Wasting ◽  
Lake Agassiz ◽  
Glacial Lake Agassiz ◽  
Stratigraphic Position ◽  
History Of

Sections along the Nelson River in northern Manitoba, outcropping upstream and downstream from Limestone Dam, record a long succession of late Quaternary events. The oldest sediment exposed consists of sandy, nonfossiliferous Sundance till of northwestern provenance and related to a Kansan or Illinoian glaciation. The paleosol developed in the Sundance till is assigned to the Yarmouthian or Sangamon interglacial on its stratigraphic position and depth of weathering. Fossiliferous, clayey Amery till of eastern provenance overlies the Sundance till and underlies the nonglacial Nelson River sediments. Aspartic acid D/L ratios of wood fragments from the Nelson River sediments correlate with an aspartic acid D/L ratio of similar wood from the Missinaibi Formation in Ontario. Beetle analysis indicates the Nelson River sediments were deposited north of the tree line under conditions more severe than those found in the area today. The deposits are believed to be of latest Sangamon or possibly Mid-Wisconsinan age. The Wisconsinan Stage is represented by the Long Spruce and Sky Pilot tills deposited by ice from the east. These tills are texturally and compositionally similar but are different colours. The overlying Henday sediments record glaciofiuvial deposition and mass wasting along the eastward retreating ice margin. Varves indicate the area was covered by glacial Lake Agassiz for less than 100 years after the ice retreated. The breakup of the Laurentide Ice Sheet in Hudson Bay and the final drainage of Lake Agassiz took place 7800–8000 years ago when the Hudson Bay Lowland was inundated by the marine water of the Tyrrell Sea. The area emerged from the Tyrrell Sea about 6500 years BP.

Late Tertiary to late Quaternary record in the Mackenzie Mountains, Northwest Territories, Canada: stratigraphy, paleosols, paleomagnetism, and chlorine - 36

1996 ◽  
Vol 33 (6) ◽  
pp. 875-895 ◽  
Author(s):  
A. Duk-Rodkin ◽  
R. W. Barendregt ◽  
C. Tarnocai ◽  
F. M. Phillips
Keyword(s):  
Late Quaternary ◽  
Ice Sheet ◽  
Climatic Conditions ◽  
Unconsolidated Sediments ◽  
Laurentide Ice Sheet ◽  
Stratigraphic Sequence ◽  
Late Tertiary ◽  
Mackenzie Mountains ◽  
Late Wisconsinan ◽  
Stratigraphic Succession

A stratigraphic sequence of unconsolidated sediments ranging in age from Late Pliocene to Late Pleistocene is recorded in the Canyon Ranges of the Mackenzie Mountains. Three of the sections (Katherine Creek, Little Bear River, and Inlin Brook) expose bedrock and Tertiary gravel overlain by colluvium and a multiple till sequence of montane origin, separated by paleosols and capped by a till of Laurentide origin. The sections are correlated on the basis of lithology, paleosol development, paleomagnetism, and chlorine dating of surface boulder erratics. A formal stratigraphic nomenclature is proposed for the deposits of this region. The sequence of glacial tills separated by paleosols reflects a long record of glacial–interglacial cycles. Soil properties from the oldest paleosol to modern soil show a general decrease in the degree of soil development, suggesting a progressive deterioration of interglacial climatic conditions. A normal–reverse–normal sequence of remanent magnetization was determined within the stratigraphic succession and assigned to the Gauss–Matuyama–Brunhes chrons, respectively. A Gauss age was assigned to the basal colluvium, an early Matuyama age (including Olduvai) to the first two tills, and a Brunhes age to the last three tills. Laurentide deposits are of Late Wisconsinan age and are restricted to the uppermost part of the stratigraphic succession. Chlorine dates for surface boulders place the all-time limit of the Laurentide Ice Sheet at about 30 ka. The Late Wisconsinan Laurentide Ice Sheet was the only continental ice to reach the Mackenzie and Richardson mountains of the northern Cordillera.

Ice-flow patterns and glacial transport in the eastern Hudson Bay region: implications for the late Quaternary dynamics of the Laurentide Ice Sheet

1995 ◽  
Vol 32 (12) ◽  
pp. 2057-2070 ◽  
Author(s):  
Michel Parent ◽  
Serge J. Paradis ◽  
Éric Boisvert
Keyword(s):  
Compositional Data ◽  
Late Quaternary ◽  
Regional Distribution ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Flow ◽  
Flow Phase ◽  
Late Wisconsinan

Recent field surveys in the eastern Hudson Bay region have led to the discovery of regional ice-flow sequences that require a significant reassessment of the late Quaternary dynamics of the Laurentide Ice Sheet. Two regional ice-flow phases can be recognized from till compositional data and from crosscutting relationships observed on striated bedrock surfaces: the oldest is directed toward the northwest and north-northwest, while the youngest is directed toward the west and includes a late-glacial deflection toward the southwest. The wide regional distribution of striae formed during the early northwestward glacial movement together with the recognition of palimpsest glacial dispersal trains associated with this phase suggest that it was a long-lived, time-transgressive regional event. The ensuing glacial movement is a regionally dominant westward ice-flow phase during which several large glacial dispersal trains were formed downglacier from distinctive bedrock sources. The largest of these trains extends westward over a distance of 120 km from Lac à l'Eau Claire to Hudson Bay. Regional glacial transport data as well as glacial and deglacial landforms indicate that this was a long-lived glacial phase, likely lasting throughout the Late Wisconsinan glacial maximum and until déglaciation about 8000 BP. The erosional and depositional record of the northwestward ice-flow event is quite comparable to that of the ensuing glacial phase, and it is thus thought to represent the Early Wisconsinan glacial maximum. In view of the large regional extent of the northwestward ice-flow phase, it must postdate the early buildup of the ice sheet. Along the southeastern Hudson Bay coast, the Late Wisconsinan westward glacial movement was followed by a southwestward deflection that was likely caused by glacial streaming prior to 8000 BP in James Bay, in response to calving and surging into Glacial Lake Ojibway.

scholarly journals Evidence from 40Ar/39Ar Ages for a Churchill province source of ice-rafted amphiboles in Heinrich layer 2

1996 ◽  
Vol 42 (142) ◽  
pp. 440-446 ◽  
Author(s):  
Roberto H. Gwiazda ◽  
Sidney R. Hemming ◽  
Wallace S. Broecker ◽  
Tullis Onsttot ◽  
Chris Mueller
Keyword(s):  
North Atlantic ◽  
Drainage Basin ◽  
Ice Sheets ◽  
Bimodal Distribution ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Glacial Sediment ◽  
The North ◽  
Layer 2 ◽  
Eastern North Atlantic

Abstract40Ar/39Ar ages of most single ice-ratted amphiboles from Heinrich layer 2 (H2) from a core in the Labrador Sea, a core in the eastern North Atlantic and a core in the western North Atlantic range from 1600 to 2000 Ma. This range is identical to that for K/Ar ages from the Churchill province of the Canadian Shield that outcrops at Hudson Strait and forms the basement of the northern part of Hudson Bay. The ambient glacial sediment includes some younger and older grains derived from Paleozoic, Mesoproterozoic and Archean sources, but still the majority of the amphiboles have ages in the 1600–2000 Ma interval. The Ca/K ratios of these 1600–2000 Ma old amphiboles, however, have a bimodal distribution in contrast with the uniformity of the Ca/K ratios of H2 amphiboles. This indicates that 1600–2000 Ma old amphiboles of the ambient sediment were derived from an additional Early Proterozoic source besides Churchill province. In H2, Churchill-derived grains constitute 20–40% of the ice-rafted debris (IRD). The fraction in the ambient glacial sediment is 65–80%. Results presented here are consistent with the hypothesis that Heinrich events were produced by a sudden intensification of the iceberg discharge through Hudson Strait that mixed, in the North Atlantic, with icebergs that continued to calve from other ice sheets. The shift from mixed sources in the background sediment to a large dominance of Churchill province grains in H2 indicates that, even if calving of other ice sheets intensified during the Heinrich episode, the increase in the iceberg discharge via Hudson Strait from the Hudson Bay drainage basin of the Laurentide ice sheet was by far the largest.

Holocene deltaic sedimentation along an emerging coast: Nastapoka River delta, eastern Hudson Bay, Quebec

2002 ◽  
Vol 39 (4) ◽  
pp. 505-518 ◽  
Author(s):  
Caroline Lavoie ◽  
Michel Allard ◽  
Philip R Hill
Keyword(s):  
River Delta ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Fluvial Erosion ◽  
Fine Grained ◽  
Isostatic Rebound ◽  
Geophysical Surveys ◽  
Deltaic Sedimentation ◽  
Forced Regression ◽  
Natural Laboratory

Eastern Hudson Bay is characterized by falling relative sea level as a result of post-glacial isostatic rebound, which makes the region a natural laboratory for rapid forced regression, where the evolution of deltaic systems and offshore sedimentation patterns can be studied. A multidisciplinary approach involving airphoto analysis, offshore geophysical surveys, sediment coring, and facies and diatom analyses was used in this study of the Nastapoka River delta. The delta has formed as a result of the fluvial erosion of emerged Quaternary sediments but is mainly subaqueous. Offshore, in the prodelta zone, the oldest deposits are glaciomarine, laid down when the ice front of the receding Laurentide ice sheet stood on the Nastapoka hills some 7700–6800 years BP. Lateral equivalents of this glaciomarine unit are presently exposed on land. The shallow-water platform of the delta shows a thin surficial unit of wave-worked sand that overlies fine-grained, deeper water deposits derived from erosion of clay soils in the river catchment a few centuries ago, probably during periods of intense thermokarst activity. As the isostatic uplift continues, the deltaic platform will gradually emerge and be incised by the river channel.

scholarly journals Objective Reconstructions of the Late Wisconsinan Laurentide Ice Sheet and the Significance of Deformable Beds

2007 ◽  
Vol 39 (3) ◽  
pp. 229-238 ◽  
Author(s):  
D. A. Fisher ◽  
N. Reeh ◽  
K. Langley
Keyword(s):  
Yield Stress ◽  
Flow Direction ◽  
Three Dimensional ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Ice Streams ◽  
Ice Flow ◽  
Surface Slopes ◽  
Late Wisconsinan

ABSTRACT A three dimensional steady state plastic ice model; the present surface topography (on a 50 km grid); a recent concensus of the Late Wisconsinan maximum margin (PREST, 1984); and a simple map of ice yield stress are used to model the Laurentide Ice Sheet. A multi-domed, asymmetric reconstruction is computed without prior assumptions about flow lines. The effects of possible deforming beds are modelled by using the very low yield stress values suggested by MATHEWS (1974). Because of low yield stress (deforming beds) the model generates thin ice on the Prairies, Great Lakes area and, in one case, over Hudson Bay. Introduction of low yield stress (deformabie) regions also produces low surface slopes and abrupt ice flow direction changes. In certain circumstances large ice streams are generated along the boundaries between normal yield stress (non-deformable beds) and low yield stress ice (deformabie beds). Computer models are discussed in reference to the geologically-based reconstructions of SHILTS (1980) and DYKE ef al. (1982).

Late Quaternary Paleotemperatures Derived from a Speleothem from Cango Caves, Cape Province, South Africa

1992 ◽  
Vol 37 (2) ◽  
pp. 203-213 ◽  
Author(s):  
A.S. Talma ◽  
John C. Vogel
Keyword(s):  
South Africa ◽  
Isotopic Composition ◽  
Late Quaternary ◽  
Carbon Isotopic Composition ◽  
Temperature Record ◽  
The Past ◽  
Carbon Isotopic ◽  
Groundwater Aquifer ◽  
Combining Data ◽  
The Last Glacial

AbstractAn oxygen isotope temperature record over a large part of the past 30,000 yr has been obtained for the southern Cape Province of South Africa by combining data on the isotopic composition of a stalagmite from a deep cave with that of a confined groundwater aquifer in the same region. Results show that temperatures during the last glacial maximum were on average about 6°C lower than those today, with peaks up to 7°C lower. A detailed analysis of the past 5000 yr suggests multiple fluctuations, with generally lower temperatures (1–2°C) around 4500 and 3000 yr B.P. The carbon isotopic composition of the stalagmite indicates significant vegetation changes between the late Pleistocene and today, and also during the second half of the Holocene.

Recent Advance of the Arctic Treeline Along the Eastern Coast of Hudson Bay

1995 ◽  
Vol 83 (6) ◽  
pp. 929 ◽  
Author(s):  
Kateri Lescop-Sinclair ◽  
Serge Payette
Keyword(s):  
The Arctic ◽  
Eastern Coast ◽  
Hudson Bay ◽  
Arctic Treeline

scholarly journals Simulating the Early Holocene demise of the Laurentide Ice Sheet with BISICLES (public trunk revision 3298)

2020 ◽  
Vol 13 (9) ◽  
pp. 4555-4577
Author(s):  
Ilkka S. O. Matero ◽  
Lauren J. Gregoire ◽  
Ruza F. Ivanovic
Keyword(s):  
Mass Balance ◽  
General Circulation ◽  
Ice Sheet ◽  
Circulation Model ◽  
Early Holocene ◽  
Laurentide Ice Sheet ◽  
Hudson Bay ◽  
Surface Mass Balance ◽  
Surface Mass ◽  
The North

Abstract. Simulating the demise of the Laurentide Ice Sheet covering Hudson Bay in the Early Holocene (10–7 ka) is important for understanding the role of accelerated changes in ice sheet topography and melt in the 8.2 ka event, a century long cooling of the Northern Hemisphere by several degrees. Freshwater released from the ice sheet through a surface mass balance instability (known as the saddle collapse) has been suggested as a major forcing for the 8.2 ka event, but the temporal evolution of this pulse has not been constrained. Dynamical ice loss and marine interactions could have significantly accelerated the ice sheet demise, but simulating such processes requires computationally expensive models that are difficult to configure and are often impractical for simulating past ice sheets. Here, we developed an ice sheet model setup for studying the Laurentide Ice Sheet's Hudson Bay saddle collapse and the associated meltwater pulse in unprecedented detail using the BISICLES ice sheet model, an efficient marine ice sheet model of the latest generation which is capable of refinement to kilometre-scale resolutions and higher-order ice flow physics. The setup draws on previous efforts to model the deglaciation of the North American Ice Sheet for initialising the ice sheet temperature, recent ice sheet reconstructions for developing the topography of the region and ice sheet, and output from a general circulation model for a representation of the climatic forcing. The modelled deglaciation is in agreement with the reconstructed extent of the ice sheet, and the associated meltwater pulse has realistic timing. Furthermore, the peak magnitude of the modelled meltwater equivalent (0.07–0.13 Sv) is compatible with geological estimates of freshwater discharge through the Hudson Strait. The results demonstrate that while improved representations of the glacial dynamics and marine interactions are key for correctly simulating the pattern of Early Holocene ice sheet retreat, surface mass balance introduces by far the most uncertainty. The new model configuration presented here provides future opportunities to quantify the range of plausible amplitudes and durations of a Hudson Bay ice saddle collapse meltwater pulse and its role in forcing the 8.2 ka event.

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