Lithostratigraphie et dynamique glaciaires au Wisconsinien, île d'Anticosti, golfe du Saint-Laurent

1987 ◽  
Vol 24 (9) ◽  
pp. 1847-1858 ◽  
Author(s):  
Luc St-Pierre ◽  
Q. H. J. Gwyn ◽  
J. M. M. Dubois
Keyword(s):  
Marine Sediments ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
The South ◽  
Ice Cap ◽  
South West ◽  
Slow Moving ◽  
Late Wisconsinan ◽  
Anticosti Island ◽  
Shell Fragments

The Laurentide Ice Sheet deposited three tills on Anticosti Island. The oldest, the Rivière à la Patate Till, was formed by southeastward-flowing ice as determined from till fabrics. The till has an estimated age of 85 000 years BP based on the aminoacid racemization of shell fragments in overlying marine sediments. Thus it is probably Early Wisconsinan in age. The Middle Wisconsinan Rivière Jupiter Till and the Late Wisconsinan Île d'Anticosti Till are the result of the southwest-flowing Laurentide ice. The ice flowed without restriction though without accomplishing deep erosion of the bedrock, as indicated by glaciotectonic structures and till fabrics. However, striated blocks and pebbles in the tills reveal that basal shearing occurred. The ice limit in the Gulf of St. Lawrence from about 36 000 years BP onwards was located along the south coast of the island. This was the result of active calving at the margin of the relatively slow moving ice sheet. During retreat of the ice sheet, an ice cap became isolated on the island. It appears to have remained active in the western part of the island, where it formed the Sainte-Marie Moraine on the south, west, and north coasts, but was less active in the eastern part of the island, where a loose, sandy, but rare till (the Sainte-Marie Till) is the only proof of its activity. Deeper water in the eastern end of the Jacques-Cartier Strait, north of the island, accelerated ice calving and thus probably reduced the ice dynamic in the eastern part of the island. The names of tills used here are proposed as formal nomenclature.

Genesis of carbonate till in the lee sides of Precambrian Shield uplands, Hemlo area, Ontario

1987 ◽  
Vol 24 (10) ◽  
pp. 2004-2015 ◽  
Author(s):  
Stephen R. Hicock
Keyword(s):  
Ice Sheet ◽  
Glacial Maximum ◽  
Laurentide Ice Sheet ◽  
The South ◽  
Precambrian Shield ◽  
Basal Zone ◽  
Compressive Flow ◽  
Late Wisconsinan ◽  
Basal Till

Near Hemlo, Ontario, highly calcareous till is confined to areas located downglacier from Precambrian uplands, at least 150 km from the Paleozoic–Precambrian boundary. It comprises subglacial meltout till between lodgment tills, and the calcareous package overlies noncalcareous basal till (not studied) and underlies noncalcareous supraglacial meltout till. The tills can be distinguished by textural, carbonate, and clast compositions. Glaciotectonic deformations, stone fabrics and striae, and stone provenance from the tills, as well as erosional and depositional landforms, indicate that ice advanced to the south–southwest across bedrock contacts and over Precambrian uplands.Deposition of all five tills can be explained with one glacial event. As the Late Wisconsinan margin of the Laurentide ice sheet advanced against uplands about 20 km northeast of Hemlo it experienced compressive flow while depositing the non calcareous basal till. Upshearing of stoss-side local debris high into the ice also occurred as englacial ice overrode the slowed basal zone. Once over the upland, englacial ice assumed extending flow, and downshearing of distal debris, which was deposited as calcareous lodgment till on the lee sides of uplands. After the glacial maximum, the glacier ceased internal movement and subglacial meltout till was laid down. A late reactivation of the ice deposited the upper lodgment till and final stagnation formed the supraglacial meltout till.

scholarly journals Data on elemental concentrations in marine sediments from the South and South West of England

Data in Brief ◽  
2021 ◽  
Vol 35 ◽  
pp. 106901
Author(s):  
Jonathan Richir ◽  
Simon Bray ◽  
Tom McAleese ◽  
Gordon J. Watson
Keyword(s):  
Marine Sediments ◽  
The South ◽  
Elemental Concentrations ◽  
South West

Absence of Glaciation in Illinois during Marine Isotope Stages 3 through 5

1996 ◽  
Vol 46 (1) ◽  
pp. 19-26 ◽  
Author(s):  
B. Brandon Curry ◽  
Milan J. Pavich
Keyword(s):  
Oxygen Isotope ◽  
Late Stage ◽  
Lake Michigan ◽  
Early Stage ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Argillic Horizon ◽  
Late Wisconsinan ◽  
Lake Michigan Lobe

A10Be inventory and14C ages of material from a core from northernmost Illinois support previous interpretations that this area was ice free from ca. 155,000 to 25,000 yr ago. During much of this period, from about 155,000 to 55,000 yr ago, 10Be accumulated in the argillic horizon of the Sangamon Geosol. Wisconsinan loess, containing inherited 10Be, was deposited above the Sangamon Geosol from ca. 55,000 to 25,000 yr ago and was subsequently buried by late Wisconsinan till deposited by the Lake Michigan Lobe of the Laurentide Ice Sheet. The Sangamonian interglacial stage has been correlated narrowly to marine oxygen isotope substage 5e; our data indicate instead that the Sangamon Geosol developed during late stage 6, all of stages 5 and 4, and early stage 3.

Pleistocene stratigraphy, paleopedology, and paleoecology of a multiple till sequence exposed on the Little Bear River, Western District of Mackenzie, N.W.T., Canada

1993 ◽  
Vol 30 (4) ◽  
pp. 851-866 ◽  
Author(s):  
O. L. Hughes ◽  
C. Tarnocai ◽  
C. E. Schweger
Keyword(s):  
Transition Zone ◽  
Ice Sheet ◽  
Climatic Conditions ◽  
Canadian Shield ◽  
Laurentide Ice Sheet ◽  
Spruce Forest ◽  
River Section ◽  
Valley Glacier ◽  
Bear River ◽  
Late Wisconsinan

The Little Bear River section lies in a transition zone between Mackenzie Lowland and Canyon Ranges of Mackenzie Mountains. Within the transition zone, the maximum extent of the Laurentide ice sheet overlaps the former extent of montane glaciers that emanated from the higher parts of Canyon Ranges or from the still higher Backbone Ranges to the southwest. Five montane tills, each with a paleosol developed in its upper part, indicate five separate glaciations during each of which a valley glacier emanating from the headwaters of Little Bear River extended eastward into the transition zone. The uppermost of the montane tills is overlain by boulder gravel containing rocks of Canadian Shield origin deposited by the Laurentide ice sheet.Solum and B horizon depths, red colours, and lack of leaching and cryoturbation indicate that although each successive interglacial interval was cooler than the preceding one, even the last of the intervals was warmer than the Holocene. Climatic conditions during one of the intervals inferred from the paleobotanic data, particularly spruce forest development, are consistent with conditions inferred from the associated paleosol.The uppermost of the montane tills is thought to correlate with till of Reid (Illinoian) age in central Yukon. The paleosol developed on that till is, accordingly, thought to correlate with the Diversion Creek paleosol developed on drift of Reid age. The Laurentide boulder gravel is assigned to a stade of Hungry Creek Glaciation of Late Wisconsinan age. The Laurentide ice sheet reached its apparent all-time western limit during the Hungry Creek Glaciation maximum.

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).

Expanded Late Wisconsinan ice cap and ice sheet margins in the western Queen Elizabeth Islands, Arctic Canada

2014 ◽  
Vol 91 ◽  
pp. 146-164 ◽  
Author(s):  
F. Chantel Nixon ◽  
John H. England
Keyword(s):  
Ice Sheet ◽  
Arctic Canada ◽  
Ice Cap ◽  
Late Wisconsinan

scholarly journals Glaciological Reconnaissance of the Sukkertoppen Ice Cap, South-West Greenland

1963 ◽  
Vol 4 (36) ◽  
pp. 813-816 ◽  
Author(s):  
C. Bull
Keyword(s):  
Snow Accumulation ◽  
The South ◽  
West Greenland ◽  
Ice Cap ◽  
South West ◽  
Eastern Edge

AbstractGravity studies indicate that the Sukkertoppen ice cap is about 400 m. thick. The annual snow accumulation increases westwards from about 13 g. cm.−2near the eastern edge of the ice cap to about 34 g. cm.−2near Mount Atter, in the south-west. Probably all of the ice cap is “temperate”.

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.

scholarly journals Late Wisconsinan grounding zones of the Laurentide Ice Sheet margin off the Québec North Shore (NW Gulf of St Lawrence)

2018 ◽  
Vol 475 (1) ◽  
pp. 241-259 ◽  
Author(s):  
P. Lajeunesse ◽  
P. Dietrich ◽  
J.-F. Ghienne
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
North Shore ◽  
Late Wisconsinan

Modelling Last Glacial Maximum ice cap with the Parallel Ice Sheet Model to infer palaeoclimate in south‐west Turkey

2020 ◽  
Vol 35 (7) ◽  
pp. 935-950
Author(s):  
Adem Candaş ◽  
M. Akif Sarikaya ◽  
Oğuzhan KÖSE ◽  
Ömer L. Şen ◽  
Attila Çiner
Keyword(s):  
Last Glacial Maximum ◽  
Ice Sheet ◽  
Glacial Maximum ◽  
Last Glacial ◽  
Ice Cap ◽  
South West
Sign in / Sign up

Export Citation Format

Share Document