Sedimentology, stratigraphy, and geomorphology of glacial Lake Calgary at Cochrane, Alberta, Canada

1999 ◽  
Vol 36 (5) ◽  
pp. 791-803 ◽  
Author(s):  
Timothy G Fisher
Keyword(s):  
Field Data ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Fluvial Sediment

Stratigraphic and sedimentologic field data in the Cochrane, Alberta, area demonstrate that glaciolacustrine sediment comprising the Calgary Formation underlies glaciofluvial and fluvial sediment of the Bighill Creek Formation, previously dated at 11.4 ka BP. A continuous, conformable contact between sediments of glacial Lake Calgary and underlying till indicates that the lake was coeval with initial deglaciation of the area. The lake formed during retreat of the Cordilleran ice up the Bow Valley that was once previously coalescent with the Laurentide Ice Sheet. Rhythmic, graded, and convoluted glaciolacustrine sediments record continuous and high rates of sedimentation in this reach of glacial Lake Calgary, further implying that the lake formed early in deglacial time.

The recession of the Laurentide Ice Sheet in southeast Northwest Territories during the Pleistocene-Holocene transition

2020 ◽  
Author(s):  
Samuel E. Kelley ◽  
Brent Ward ◽  
Jason Briner ◽  
Martin Ross ◽  
Philippe Normandeau ◽  
...  
Keyword(s):  
Northwest Territories ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Lake Basin ◽  
Great Slave Lake ◽  
Northwestern Margin ◽  
Ice Retreat ◽  
Oriented Parallel ◽  
Exposure Ages

<p>The Laurentide Ice Sheet (LIS) during the Pleistocene-Holocene transition provides a useful natural laboratory for examining the behavior of a mid- to high-latitude ice sheet during a period of climatically driven ice sheet thinning and retreat. While the timing and pattern of Pleistocene recession of the LIS are well-constrained along the southern and eastern margins, there is limited chronology constraining the ice margin retreat along the northwestern margin. Here we present new cosmogenic <sup>10</sup>Be exposure ages retreat of the western margin of the LIS during the Pleistocene-Holocene transition. Sampling was performed along three transects located between the northern shore of Great Slave Lake and Lac de Gras. Each of the transects is oriented parallel to the inferred ice retreat direction in an attempt to capture a regional rate of retreat. Our new <sup>10</sup>Be cosmogenic exposure ages from the southeastern Northwest Territories demonstrate that regional deglaciation occurred around 11,000 years ago. The population of ages broadly overlaps, indicating that either the retreat occurred within the resolution of our chronology or that the ice sheet experienced widespread stagnation and rapid down-wasting. These ages, not corrected for changes in atmospheric depth due to isostatic rebound, are older than minimum limiting radiocarbon constraints by ~1000 years, indicating that existing LIS reconstructions may underestimate the timing and pace of ice margin recession for this sector. Constraining the timing of the recession of the northwest sector of the LIS has the potential to inform our understanding about the damming of large proglacial lakes, such as Glacial Lake McConnell. The ages from our southern transect, collected from elevated bedrock hills, indicate LIS retreat from through the McConnell basin occurred after 12,000 years ago, and thus constitute maximum limiting constraints on the expansion of Glacial Lake McConnell southeastward into the present-day Great Slave Lake basin. Our chronology, combined with other emerging cosmogenic exposure ages constraining LIS deglaciation indicates retreat of the ice margin over 100s of kilometres during the Pleistocene-Holocene transition, exhibiting no evidence of a significant readvance during the Younger Dryas stadial.</p>

Evidence of late glacial paleoseismicity from submarine landslide deposits within Lac Dasserat, northwestern Quebec, Canada

2016 ◽  
Vol 86 (2) ◽  
pp. 184-199 ◽  
Author(s):  
Gregory R. Brooks
Keyword(s):  
Ice Sheet ◽  
Late Glacial ◽  
Relative Strength ◽  
Submarine Landslide ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Event Horizons ◽  
Lake Ojibway

AbstractAn integrated seismo- and chronostratigraphic investigation at Lac Dasserat, northwestern Quebec, identified 74 separate failures within eight event horizons. Horizons E and B, and H and G have strong or moderately-strong multi-landslide signatures, respectively, composed of 11-23 failures, while horizons F, D, C, and A have minor landslide signatures consisting of a single or pair of deposit(s). Cores collected at six sites recovered glacial Lake Ojibway varve deposits that are interbedded with the event horizons. The correlation of the varves to the regional Timiskaming varve series allowed varve ages or ranges of varve ages to be determined for the event horizons. Horizons H, G, E, and B are interpreted to be evidence of paleoearthquakes with differing levels of interpretative confidence, based on the relative strength of the multi-landslide signatures, the correlation to other disturbed deposits of similar age in the region, and the lack or possibility of alternative aseismic mechanisms. The four interpreted paleoearthquakes occurred between 9770 ± 200 and 8470 ± 200 cal yr BP, when glacial Lake Ojibway was impounded behind the Laurentide Ice Sheet during deglaciation. They probably represent an elevated period of seismicity at deglaciation that was driven by crustal unloading.

Changes in the Bathymetry and Volume of Glacial Lake Agassiz between 9200 and 7700 14C yr B.P.

2002 ◽  
Vol 57 (2) ◽  
pp. 244-252 ◽  
Author(s):  
David W. Leverington ◽  
Jason D. Mann ◽  
James T. Teller
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Areal Extent ◽  
Lake Agassiz ◽  
Southern Margin ◽  
Glacial Lake Agassiz ◽  
Water Volumes ◽  
Two Phases ◽  
Lake Waters

AbstractComputer reconstructions of the bathymetry of the lake were used to quantify variations in the size and form of Lake Agassiz during its final two phases (the Nipigon and Ojibway phases), between about 9200 and 7700 14C yr B.P. (ca. 10,300–8400 cal yr B.P.). New bathymetric models for four Nipigon Phase stages (corresponding to the McCauleyville, Hillsboro, Burnside, and The Pas strandlines) indicate that Lake Agassiz ranged between about 19,200 and 4600 km3 in volume and 254,000 and 151,000 km2 in areal extent at those times. A bathymetric model of the last (Ponton) stage of the lake, corresponding to the period in which Lake Agassiz was combined with glacial Lake Ojbway to the east, shows that Lake Agassiz–Ojibway was about 163,000 km3 in volume and 841,000 km2 in areal extent prior to the final release of lake waters into the Tyrrell Sea. During the Nipigon Phase, a number of catastrophic releases of water from Lake Agassiz occurred as more northerly (lower) outlets were made available by the retreating southern margin of the Laurentide Ice Sheet; we estimate that each of the four newly investigated Nipigon Phase releases involved water volumes of between 1600 and 2300 km3. The final release of Lake Agassiz waters into the Tyrrell Sea at about 7700 14C yr B.P. is estimated to have been about 163,000 km3 in volume.

Paleotopographic reconstructions of the eastern outlets of glacial Lake Agassiz

2003 ◽  
Vol 40 (9) ◽  
pp. 1259-1278 ◽  
Author(s):  
David W Leverington ◽  
James T Teller
Keyword(s):  
Great Lakes ◽  
Lake Level ◽  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Lake Agassiz ◽  
Flow Paths ◽  
Southern Margin ◽  
Glacial Lake Agassiz ◽  
Complex Manner

Paleotopographic reconstructions of the eastern outlets of glacial Lake Agassiz provide a foundation for understanding the complex manner in which terrain morphology controlled the routing of overflow through the eastern outlets during the lake's Nipigon Phase (ca. 9400–8000 14C years BP) and for understanding the causes of outlet-driven declines in lake level during that period. Although flow paths across the divide between the Agassiz and Nipigon basins were numerous, eastward releases from Lake Agassiz to glacial Lake Kelvin (modern Lake Nipigon) were channeled downslope into a relatively small number of major channels that included the valleys of modern Kopka River, Ottertooth Creek, Vale Creek, Whitesand River, Pikitigushi River, and Little Jackfish River. From Lake Kelvin, these waters overflowed into the Superior basin. The numerous lowerings in lake level between stages of the Nipigon Phase, controlled by topography and the position of the retreating southern margin of the Laurentide Ice Sheet, had magnitudes of between 8 and 58 m, although some of these drawdowns may have occurred as multiple individual events that could have been as small as several metres. The total volumes of water released in association with these drops were as great as 8100 km3, and for all Nipigon stages were probably between about 140 and 250 km3 per metre of lowering. The topographic reconstructions demonstrate that Lake Agassiz occupied the area of glacial Lake Nakina (located northeast of modern Lake Nipigon) by the The Pas stage (ca. 8000 14C years BP) and that Lake Agassiz drainage through the Nipigon basin to the Great Lakes ended before the succeeding Gimli stage.

LAURENTIDE ICE SHEET READVANCE CA. 21.7 K CAL YR BP AND FORMATION OF GLACIAL LAKE EMINENCE, SOUTH-CENTRAL INDIANA

2017 ◽  
Author(s):  
Henry M. Loope ◽  
◽  
Robert J. Autio ◽  
G. William Monaghan ◽  
José Luis Antinao ◽  
...  
Keyword(s):  
Ice Sheet ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
South Central

scholarly journals Ice Scours in the Sediments of Glacial Lake Iroquois, Prince Edward County, Eastern Ontario

2007 ◽  
Vol 46 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Robert Gilbert ◽  
Karen J. Handford ◽  
John Shaw
Keyword(s):  
Shallow Water ◽  
Ice Sheet ◽  
Ground Surface ◽  
Laurentide Ice Sheet ◽  
Glacial Lake ◽  
Lake Ice ◽  
Prince Edward County ◽  
Westerly Direction ◽  
Eastern Ontario

ABSTRACT Straight or slightly curved ice scours are found in thin glacilacustrine sediment of eastern Lake Iroquois, especially near the crest of an escarpment in Prince Edward County. They are large (to 3.57 km long and 174 m wide), shallow (about 1 m deep) and oriented in a nearly westerly direction. Irregular ridges of sediment have been pushed up along the sides and at the western end of some scours. Bedrock is near the ground surface, but had little influence on the formation of the scours. Based on their shape, location and pattern, we conclude that the scours were most likely formed in shallow water of the short-lived Sydney phase of Lake Iroquois by lake ice driven by prevailing northeasterly winds from the retreating Laurentide Ice Sheet.

Sign in / Sign up

Export Citation Format

Share Document