scholarly journals Age Relationships of Laurentide and Montane Glaciations, Mackenzie Mountains, Northwest Territories

2007 ◽  
Vol 45 (1) ◽  
pp. 79-90 ◽  
Author(s):  
Alejandra Duk-Rodkin ◽  
Owen L. Hughes
Keyword(s):  
Northwest Territories ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Mountain Front ◽  
Bear River ◽  
Mackenzie Mountains ◽  
Late Wisconsinan

ABSTRACT The Mackenzie Mountains were glaciated repeatedly by large valley glaciers that emanated from the Backbone Ranges, and by much smaller valley glaciers that emanated from peaks in the Canyon Ranges. During the Late Wisconsinan the Laurentide Ice Sheet reached its all-time maximum position. The ice sheet pressed against the Canyon Ranges and moved up major valleys causing the diversion of mountain waters and organizing a complex meltwater system that drained across mountain interfluve areas towards the northwest. Two ages of moraines deposited by montane glaciers occur widely in the Mackenzie Mountains. Near the mountain front certain of the older moraines have been truncated by the Laurentide Ice Sheet, and others have been incised by meltwater streams emanating from the Laurentide ice margin, indicating that these older moraines predate the maximum Laurentide advance. Locally, certain of the younger montane moraines breach moraines and other ice marginal features of the Laurentide maximum, indicating that the younger montane glaciation post-dated the Laurentide maximum. Some large montane glaciers extended out from the mountains to merge with the retreating Laurentide Ice Sheet. There are several localities that display the age relationships between montane and Laurentide glaciations such as Dark Rock Creek, Durkan-Lukas Valley, Little Bear River and Katherine Creek. The older of the local montane glaciations is correlated tentatively with Reid Glaciation (lllinoian?) of central Yukon, and the younger with the Late Wisconsinan McConnell Glaciation. The Laurentide Glaciation is correlated with Hungry Creek Glaciation of Bonnet Plume Depression, which probably culminated about 30,000 years ago or somewhat later.

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.

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.

Laurentide and montane glaciation along the Rocky Mountain Foothills of northeastern British Columbia

2007 ◽  
Vol 44 (4) ◽  
pp. 445-457 ◽  
Author(s):  
Jan M Bednarski ◽  
I Rod Smith
Keyword(s):  
British Columbia ◽  
Ice Sheet ◽  
Rocky Mountain ◽  
Laurentide Ice Sheet ◽  
Cosmogenic Dating ◽  
Surficial Geology ◽  
Continental Divide ◽  
Mountain Front ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

Mapping the surficial geology of the Trutch map area (NTS 94G) provides new data on the timing of continental and montane glaciations along the Foothills of northeastern British Columbia. Striated surfaces on mountain crests were dated to the Late Wisconsinan substage by cosmogenic dating. The striations were produced by eastward-flowing ice emanating from the region of the Continental Divide. This ice was thick enough to cross the main ranges and overtop the Rocky Mountain Foothill summits at 2000 m above sea level (asl). It is argued here that such a flow, unhindered by topography, could only have been produced by the Cordilleran Ice Sheet and not by local cirque glaciation. During this time, the Cordilleran Ice Sheet dispersed limestone and schist erratics of western provenance onto the plains beyond the mountain front. Conversely, the Laurentide Ice Sheet did not reach its western limit in the Foothills until after Cordilleran ice retreated from the area. During its maximum, the Laurentide ice penetrated the mountain valleys up to 17 km west of the mountain front, and deposited crystalline erratics from the Canadian Shield as high as 1588 m asl along the Foothills. In some valleys a smaller montane advance followed the retreat of the Laurentide Ice Sheet.

Landform assemblages produced by the Laurentide Ice Sheet in northeastern British Columbia and adjacent Northwest Territories — constraints on glacial lakes and patterns of ice retreatThis article is one of a selection of papers published in this Special Issue on the theme Geology of northeastern British Columbia and northwestern Alberta: diamonds, shallow gas, gravel, and glaciers.

2008 ◽  
Vol 45 (5) ◽  
pp. 593-610 ◽  
Author(s):  
Jan M. Bednarski
Keyword(s):  
British Columbia ◽  
Northwest Territories ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Ice Flow ◽  
The North ◽  
Relative Chronology ◽  
Mountain Front ◽  
Ice Retreat ◽  
Cordilleran Ice Sheet

The Laurentide Ice Sheet reached the Canadian Cordillera during the last glacial maximum in northeastern British Columbia and adjacent Northwest Territories and all regional drainage to unglaciated areas in the north was dammed by the ice. Converging ice-flow patterns near the mountain front suggest that the Laurentide Ice Sheet likely coalesced with the Cordilleran Ice Sheet during the last glaciation. With deglaciation, the ice masses separated, but earlier ice retreat in the south meant that meltwater pooled between the mountain front and the Laurentide margin. The level of the flooding was controlled by persistent ice cover on the southern Franklin Mountains. Glacial Lake Liard formed when the Laurentide Ice Sheet retreated east of the southern Liard Range and, at its maximum extent, may have impounded water at least as far south as the Fort Nelson River. Deglaciation of the plains was marked by local variations in ice flow caused by a thin ice sheet becoming more affected by the topography and forming lobes in places. These lobes caused diversions in local drainage readily traced by abandoned meltwater channels. Radiocarbon ages from adjacent areas suggest the relative chronology of deglaciation presented here occurred between 13 and 11 ka BP.

scholarly journals Pleistocene Montane Glaciations in the Mackenzie Mountains, Northwest Territories

2007 ◽  
Vol 46 (1) ◽  
pp. 69-83 ◽  
Author(s):  
Alejandra Duk-Rodkin ◽  
Owen L. Hughes
Keyword(s):  
Northwest Territories ◽  
Ice Sheet ◽  
Mountain Region ◽  
Mountain River ◽  
The West ◽  
Continental Divide ◽  
Single Pattern ◽  
Mackenzie Mountains ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

ABSTRACT During the Pleistocene the Mackenzie Mountains were affected by a series of glaciations. Through all the glaciations a single pattern seems to have been repeated: a Cordilleran ice sheet formed to the west of the continental divide and montane valley glaciers formed to the east. The montane glaciers in the Mackenzie Mountains emanated from two differents sources: a) a glacial divide, lying generally along the topographic divide between Pacific and Arctic drainage, and dividing the westerly flowing Cordilleran Ice Sheet from easterly and northerly flowing montane glaciers, b) local peaks in the Canyon Ranges. There were two well defined glacial advances in this mountain region: lllinoian, Late Wisconsinan, and one or more less defined pre-lllinoian glaciation(s). lllinoian and Late Wisconsinan glaciations are herein named Mountain River and Gayna River glaciations respectively. These advances are usually identifiable in valleys by frontal and segments of lateral moraines and glacial erosional features. Pre-lllinoian glaciation(s) have been recognized so far only in stratigraphie sections. The older advances were more extensive than the Gayna River advance; associated deposits occur higher on the valley sides and further down the valley than those associated with Gayna River Glaciation. During Mountain River Glaciation some of the montane glaciers in the Canyon Ranges merged to form piedmont glaciers. In contrast, during Gayna River Glaciation, the local glaciers consisted of single tongues, and these were mostly restricted to tributary valleys that had northward facing cirques.

Late Wisconsinan Cordilleran and Laurentide glaciation of the Peace River Valley east of the Rocky Mountains, British Columbia

2018 ◽  
Vol 55 (12) ◽  
pp. 1324-1338 ◽  
Author(s):  
Gregory M.D. Hartman ◽  
John J. Clague ◽  
René W. Barendregt ◽  
Alberto V. Reyes
Keyword(s):  
Rocky Mountains ◽  
Ice Sheet ◽  
River Valley ◽  
Laurentide Ice Sheet ◽  
Eastern Front ◽  
Peace River ◽  
Stratigraphic Framework ◽  
Mountain Front ◽  
Late Wisconsinan ◽  
Cordilleran Ice Sheet

In the past, researchers have disagreed over the maximum extent of the Cordilleran Ice Sheet in the Peace River valley during the Late Wisconsinan. Some workers argued that Cordilleran ice reached beyond the Rocky Mountains and briefly coalesced with the Laurentide Ice Sheet on the westernmost Interior Plains. In contrast, others asserted that Cordilleran ice did not reach beyond the eastern front of the Rocky Mountains. Stratigraphic interpretation of three sections within a Middle Wisconsinan paleovalley and re-examination of a previously published regional stratigraphic framework show that western-sourced ice (likely the Cordilleran Ice Sheet) extended east of the mountain front during the Late Wisconsinan, prior to the incursion of the Laurentide Ice Sheet into the area. This conclusion has implications for Cordilleran Ice Sheet reconstruction and modelling, and provides insight into the interactions between the Cordilleran and Laurentide ice sheets during the last glaciation.

The deglacial dynamics of the Laurentide and Cordilleran ice sheets in the Mackenzie Mountains, Northwest Territories, Canada

2021 ◽  
Author(s):  
Benjamin J Stoker ◽  
Martin Margold ◽  
Duane G. Froese ◽  
John C. Gosse
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Geomorphological Mapping ◽  
Dating Methods ◽  
Mountain Front ◽  
Modelling Studies ◽  
Mackenzie Mountains ◽  
Cordilleran Ice Sheet ◽  
The Individual ◽  
Glacial Landforms

<p>The northwestern sector of the Laurentide Ice Sheet coalesced with the Cordilleran Ice Sheet over the southern Mackenzie Mountains, and with local montane glaciers along the eastern slopes of the Mackenzie Mountains. Numerical modelling studies have identified rapid ice sheet thinning in this region as a major contributor to Meltwater Pulse 1A. Despite advances in remote sensing and numerical dating methods, the configuration and chronology of the northwestern sector of the Laurentide Ice Sheet have not been reconstructed in detail. The last available studies date back to the 1990s, when field surveys and mapping from aerial imagery were used to reconstruct the glacial history in the Mackenzie Mountains. Cross-cutting relations between glacial landforms and a series of <sup>36</sup>Cl cosmogenic nuclide dates were used to propose a deglacial model involving a significant readvance of the Laurentide Ice Sheet in the region. However, the chronological evidence supporting the readvance is uncertain because the individual ages are few and poorly clustered. Here we present an updated map of the glacial limits during the local Last Glacial Maximum and the recessional record in the Mackenzie Mountains, based on glacial geomorphological mapping from the ArcticDEM. We provide sixteen new <sup>10</sup>Be dates from four sites that were previously glaciated by the Laurentide Ice Sheet to constrain the deglacial sequence across the region. These dates indicate ice sheet detachment from the eastern Mackenzie Mountains at ~16 ka as summits in the mountain front became ice-free. The Mackenzie Valley at ~ 65 °N became ice-free at ~ 14 – 13  ka, towards the end of the Bølling-Allerød warm period. Combining these dates with existing <sup>10</sup>Be dates, these chronological constraints on the deglaciation of the Laurentide Ice Sheet allow us to reinterpret landform relations in the Mackenzie Mountains in order to reconstruct the ice sheet retreat. Our reconstruction provides updated constraints on the LGM extent, and the timing and pattern of deglaciation in the Mackenzie Mountains. This new understanding is useful to future efforts to quantify past sea-level contributions from the western Laurentide Ice Sheet.</p>

Glacial history and stratigraphy of the Alberta portion of the Kananaskis Lakes map area

1980 ◽  
Vol 17 (4) ◽  
pp. 459-477 ◽  
Author(s):  
L. E. Jackson Jr.
Keyword(s):  
Ice Sheets ◽  
Ice Sheet ◽  
Rocky Mountain ◽  
Laurentide Ice Sheet ◽  
Glacial History ◽  
Mountain Valley ◽  
Eastern Margin ◽  
Mountain Front ◽  
Late Wisconsinan ◽  
Land Mammal

Deposits of till, glaciofluvial, and glaciolacustrine sediments representing four glaciations are recognized in the Alberta portions of the Kananaskis Lakes 1:250 000 map sheet (82J). The oldest episode is represented by scattered erratics and patches of till above 1400 m in the Porcupine Hills. This episode involved nonsynchronous advances of Laurentide and Rocky Mountain ice sheets. The next glacial episode involved coalescence of Rocky Mountain and Laurentide ice in the eastern Foothills, north of the Porcupine Hills. The Rocky Mountain Maycroft Till, the Laurentide Maunsell Till, and the glaciolacustrine Chain Lakes Clays and Silts were deposited during this episode. The next glaciation involved the last coalescence of Rocky Mountain and Laurentide ice sheets in the vicinity of the study area. The Rocky Mountain Bow Valley Till and the mixed Rocky Mountain – Laurentide provenance Erratics Train Till were deposited during this episode along with the Foothills Erratics Train. The latest glaciation involved an advance of the Laurentide ice sheet to the eastern margin of the study area and Rocky Mountain valley glaciers to the mountain front. One readvance of Rocky Mountain valley glaciers during retreat is recognized. The glaciolacustrine Midnapore Silts and Clays were deposited due to Laurentide ice damming of Bow River valley while the Canmore and Eisenhower Junction Tills were deposited by valley glaciers. On the basis of land mammal chronology, the two oldest glaciations are believed to be Illinoian in age. Radiocarbon evidence indicates the Erratics Train Glaciation to be at least Early Wisconsinan in age and the post-Erratics Train to be of Late Wisconsinan age.

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.

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).

Sign in / Sign up

Export Citation Format

Share Document