scholarly journals Interaction of Laurentide and Cordilleran ice in the Beaver Mines area, southwestern Alberta

2002 ◽  
Vol 54 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Philip J. Holme ◽  
Stephen R. Hicock ◽  
Lionel E. Jackson
Keyword(s):  
Canadian Shield ◽  
River Valley ◽  
Ice Thickness ◽  
Glacial Lakes ◽  
Quaternary Sediments ◽  
Surficial Geology ◽  
Area Distribution ◽  
Ice Retreat ◽  
Late Wisconsinan

Abstract Surficial geology mapping of the Beaver Mines area, distribution of Canadian Shield erratics, stratigraphy of Quaternary sediments exposed along the Castle River valley and its tributaries and correlation with southwestern Alberta geochronology, indicate that Cordilleran and Laurentide ice were in contact in the lower Castle River valley during the Late Wisconsinan Substage. During this time two Cordilleran glacial advances are recognised in the lower reaches of the valley, its tributaries and the western Interior Plains: 1) an earlier advance (M1), during which ice thickness averaged between 320 - 350 m thick in the Beaver Mines area, and 2) a later readvance (M2). A single Laurentide advance (C2) into the Beaver Mines area was contemporaneous with retreat of Cordilleran ice from the M2 maximum position, resulting in coalescence of the two ice masses. This followed a C1 advance that is recognised outside the area. During montane advances, glaciers were topographically-controlled and efficiently eroded their substrates. Deglaciation was characterised by ice retreat, stagnation of detached ice masses, and damming of glacial lakes by retreating Laurentide ice.

Quaternary stratigraphy and glacial history of the Peace River valley, northeast British ColumbiaThis 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. 549-564 ◽  
Author(s):  
Gregory M.D. Hartman ◽  
John J. Clague
Keyword(s):  
British Columbia ◽  
River Valley ◽  
Quaternary Sediments ◽  
Shallow Gas ◽  
Peace River ◽  
Last Glaciation ◽  
Quaternary Stratigraphy ◽  
History Of ◽  
Late Wisconsinan ◽  
Selection Of

Two Cordilleran and three Laurentide glacial advances are recorded in Quaternary sediments and landforms in the Peace River valley, northeast British Columbia. The advances are inferred from fluvial gravels, glaciolacustrine sediments, and tills within nested paleovalleys excavated during three interglaciations and from the distribution of granitoid clasts derived from the Canadian Shield. Till of the last (Late Wisconsinan) Laurentide glaciation occurs at the surface, except where it is overlain by postglacial sediments. The advance that deposited this till was the most extensive in the study area, and the only advance definitively recognized in western Alberta south of the study area. Late Wisconsinan Cordilleran till has not been found in the study area, but Cordilleran and Laurentide ice may have coalesced briefly during the last glaciation. Support for this supposition is provided by the inferred deflection of Laurentide flutings to the southeast by Cordilleran ice. The earliest Laurentide advance may have been the least extensive of the three Laurentide events recognized in the study area. Erratics attributed to this advance occur only east of the Halfway River – Beatton River drainage divide.

Submarine and onshore end moraines in southern Newfoundland: implications for the history of late Wisconsinan ice retreat

Boreas ◽  
2008 ◽  
Vol 29 (4) ◽  
pp. 295-314 ◽  
Author(s):  
JOHN SHAW ◽  
DOUGLAS R. GRANT ◽  
JEAN-PIERRE GUILBAULT ◽  
THANE W. ANDERSON ◽  
D. RUSSELL PARROTT
Keyword(s):  
History Of ◽  
Ice Retreat ◽  
Late Wisconsinan

scholarly journals Reduced ice thickness in Arctic Transpolar Drift favors rapid ice retreat

2008 ◽  
Vol 35 (17) ◽  
Author(s):  
Christian Haas ◽  
Andreas Pfaffling ◽  
Stefan Hendricks ◽  
Lasse Rabenstein ◽  
Jean-Louis Etienne ◽  
...  
Keyword(s):  
Ice Thickness ◽  
Ice Retreat ◽  
Transpolar Drift

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.

Source and Origin of Roxana Silt and Middle Wisconsinan Midcontinent Glacial Activity

1989 ◽  
Vol 31 (3) ◽  
pp. 319-331 ◽  
Author(s):  
W. Hilton Johnson ◽  
Leon R. Follmer
Keyword(s):  
Mississippi River ◽  
Lake Michigan ◽  
Drainage System ◽  
River Valley ◽  
Upper Mississippi River ◽  
Upper Great Lakes ◽  
Mississippi River Valley ◽  
Depositional System ◽  
Stratigraphic Position ◽  
Late Wisconsinan

AbstractThick Roxana Silt (middle Wisconsinan) in central and southwestern Illinois traditionally has been interpreted as loess derived from valley-train deposits in the ancient Mississippi River valley. Winters et al. (H. A. Winters, J. J. Alford, and R. L. Rieck, Quaternary Research 29, 25–35, 1988) recently suggested that the Roxana was not directly related to glacial activity, but was derived from sediment produced by increased shoreline and spillway erosion associated with a fluctuating ancestral Lake Michigan. Because (1) paleoenvironmental and paleohydrologic conditions inferred in the hypothesis are unlikely for a loess depositional system and (2) loess did not accumulate during late Wisconsinan deglaciation under conditions similar to those hypothesized, we suggest the hypothesis should be rejected. Roxana distribution suggests the major source was drainage from the upper Mississippi River valley, and variations in loess thickness in Illinois can be explained by consideration of valley width, depth, orientation, and postdepositional erosion. Tills in the headwaters region of the ancient Mississippi drainage system in Minnesota and Wisconsin occur in the appropriate stratigraphic position and have colors and mineralogic compositions that suggest they could be the parent till of the Roxana. We believe a valley-train source for thick Roxana is most probable and urge continued consideration of middle Wisconsinan glaciation in the upper Great Lakes area.

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.

scholarly journals Quaternary geology of part of the McLeod Lake map area (NTS 093J), central British Columbia: lithostratigraphy, glacial history, and chronology

2017 ◽  
Vol 54 (10) ◽  
pp. 1063-1084
Author(s):  
David A. Sacco ◽  
Brent C. Ward ◽  
Olav B. Lian ◽  
Denny E. Maynard ◽  
Marten Geertsema
Keyword(s):  
Quaternary Geology ◽  
Similar Data ◽  
Ice Flow ◽  
Surficial Geology ◽  
Front Position ◽  
Aeolian Activity ◽  
Stratigraphic Record ◽  
Glaciofluvial Deposits ◽  
Flow Features ◽  
Ice Retreat

The coalescence and subsequent divergence of glaciers near the McLeod Lake map area during the last (Fraser) glaciation are recorded by landforms, ice-flow indicators, and the distribution of sediments. Ice initially flowed into the study area from the northwest, with at least one fluctuation in the ice-front position. Ice flow during glacial maximum was generally to the northeast and transitioned to the east during deglaciation. The Quaternary stratigraphic record spans the Fraser Glaciation and is represented by a sequence of advance glaciolacustrine sediments, multiple till units, retreat glaciolacustrine and glaciofluvial sediments, and associated postglacial aeolian material. The surficial geology is dominated by thick, streamlined till that thins where relief is high. Glaciofluvial outwash occurs mostly in northeast- and southeast-trending meltwater channels, while ice-contact glaciofluvial deposits and ablation till occur in depressions throughout the region. Extensive glaciolacustrine deposits blanket low-lying regions in the southern parts of the study area. Meltwater and ice-flow features suggest that deglaciation in the region was dominantly frontal retreat and that ice was largely active as it retreated through the study area. Postglacial aeolian activity was brief; optical dating on K-feldspar from aeolian landforms indicates that the landforms had stabilized by between 8.71–10.71 and 12.3–14.3 ka, and provides minimum ages for ice retreat. The data from the study area are evaluated with similar data from adjacent regions to develop an ice-flow history, and refine the conceptual model of deglaciation for the northern Interior Plateau.

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