Glacial dispersal and flow history, East Arm area of Great Slave Lake, NWT, Canada

Sharpe, D R; Kjarsgaard, Bruce A.; Knight, R D; Russell, H A J; Kerr, D E

doi:10.1016/j.quascirev.2017.04.011

Cited by 18 publications

(23 citation statements)

References 63 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Rampton (2000) observed partially meltwater-modified till flanking scoured corridors, and beyond corridor margins, thus highlighting the erosional role of variable width meltwater flows, capable of focused incision to produce corridors. Similar morphology has been recognized in other Keewatin corridors (Utting et al 2009;Sharpe et al 2014Sharpe et al , 2017Campbell et al 2020;Lewington et al 2020a). Extensive field-based studies have expanded the inventory of landforms associated with corridors, including various esker elements (fans, splays, and beads; Gorrell and Shaw 1990;Brennand and Sharpe 1993;Brennand 1994;Cummings 2011b), and erosional and/or depositional hummocks (Utting et al 2009;Lewington et al 2020a).…”

Section: Regional Settingsupporting

confidence: 80%

Regional stagnation of the western Keewatin ice sheet and the significance of meltwater corridors and eskers, northern Canada

et al. 2021

Self Cite

View full text Add to dashboard Cite

The glacial landsystem of western Keewatin region, northern Canada, consists of three significant events. First, was regional emplacement of subglacial sediments, mainly till (a pre-existing landscape). Second, was regional-scale erosion (land surface modification) leading to development of an integrated, anabranched network of meltwater drainage routes producing meltwater corridors. Third, was deposition of an extensive array of eskers, and related forms, within meltwater corridors. Integration of field observations, mapping and remotely-sensed data allow us to link scoured bedrock and till surfaces, truncated drumlins, scour pits, glaciofluvial terraces, boulder lags, and the extensive network of erosional corridors, as part of regional meltwater erosion events. The network of long (~100-200 km), relatively wide (~1-3 km) meltwater corridors record confined subglacial erosion that scoured sediment (and bedrock) prior to glaciofluvial sedimentation (predominately eskers). Despite considerable sediment erosion along corridors, moraines and other ice-marginal deposits are rare on the western Keewatin landscape. The absence of these features is inconsistent with deglacial models relying on step-wise active retreat of the ice-margin. Instead, we propose that deglaciation of the western Keewatin Sector of the Laurentide Ice Sheet (LIS) was controlled by regional thinning and stagnation. These findings raise fundamental questions about deglacial patterns and processes and thus suggest that further evaluation and revision of existing models of deglacial chronology for this sector of the LIS is needed..

show abstract

Section: Regional Settingsupporting

confidence: 80%

Regional stagnation of the western Keewatin ice sheet and the significance of meltwater corridors and eskers, northern Canada

et al. 2021

Self Cite

View full text Add to dashboard Cite

show abstract

“…Another feature developed by subglacial meltwater are glaciofluvial corridors or Subglacial meltwater corridors (GFC). GFCs are elongated sub‐parallel tracts in the glaciated landscape where till has been eroded and in places glaciofluvial material deposited and have been mapped mostly on areas with crystalline bedrock in Canada (St‐Onge, ; Brennand and Sharpe, ; Rampton, ; Utting et al ., ; Dredge et al ., ; Sharpe et al, ; Sharpe et al, ). Glaciofluvial corridors have similar spacing to the hummock corridors in the SSU (Table ).…”

Section: Discussionmentioning

confidence: 99%

Hummock corridors in the south‐central sector of the Fennoscandian ice sheet, morphometry and pattern

Peterson

Johnson

2017

Earth Surf Processes Landf

View full text Add to dashboard Cite

Subglacial conditions strongly influence the flow of ice‐sheets, in part due to the availability of melt water. Contemporary ice sheets are retreating and are affected by increased melting as climate warms. The south Swedish uplands (SSU) were deglaciated during the relatively warm Bølling‐Allerød interval, and by studying the glacial landforms there it is possible to increase the understanding of the subglacial environment during this period of warming. Across the study area, vast tracts of hummocks have long been recognized. However, recent mapping shows a pattern of elongated zones of hummocks radially oriented, hereafter referred to as ‘hummock corridors’. Morphometric parameters were measured on the hummock corridors using a 2 m horizontal resolution digital elevation model. Corridor width varies between 0.2 and 4.9 km and their length between 1.5 and 11.8 km. A majority of hummock corridors are incised in drumlinised till surfaces. The pattern of hummock corridors shows a clear relation to the overall ice‐flow. Further, hummock corridors do not follow topographic gradients, and in at least one place an esker overlies hummocks on the corridor floor. The lateral spacing of hummock corridors and corridor morphology are similar to tunnel valleys, eskers and glaciofluvial corridors reported elsewhere. Such relationships support a subglacial genesis of the corridors in the SSU by water driven by the subglacial hydraulic gradient and that hummock corridors are forms that can be identified as tunnel valleys and glaciofluvial corridors (GFC). Ages were assigned to hummock‐corridor cross‐sections from a deglacial reconstruction of the Fennoscandian Ice Sheet. By comparing the frequency of corridors per age interval with climate variations from a Greenland ice core, we hypothesize that an increase in the number of corridors is related to the Bølling‐Allerød warming, indicating a higher rate of delivery of surface melt water to the bed at this time. Copyright © 2017 John Wiley & Sons, Ltd.

show abstract

“…Many of the hummock tracts exist as corridors, and they occur in a radial pattern that is roughly parallel to regional iceflow direction (Figures 3 and 4). Moreover, hummock corridors have been suggested to reflect former largescale subglacial meltwater flow beneath ice sheets (Peterson & Johnson, 2018;Sharpe et al, 2017;Utting et al, 2009). Although glacial hummocks have been commonly associated with dead-ice processes, we consider the hummock tracts to be the product of multiple processes including dead-ice melting (Johnson & Clayton, 2003;Peterson & Johnson, 2018).…”

Section: Hummock Tracts and Corridorsmentioning

confidence: 99%

Glacial geomorphology between Lake Vänern and Lake Vättern, southern Sweden

2020

View full text Add to dashboard Cite

The glacial geomorphology between the lakes Vänern and Vättern is presented on a 1:220,000 scale, LiDAR-based map covering approximately 18,000 km 2. Fifteen landform units have been mapped; end moraines, De Geer moraines, drumlins, crag-and-tails, hummock tracts and corridors, irregular ridges, murtoos, eskers, deltas/sandur, outwash complexes, meltwater channels, boulder bars/sheets, the Timmersdala ridge, raised shorelines, sand dunes and prominent landslide scars (the last three are post-glacial). The area includes moraines associated with the Younger Dryas cold interval and drainage deposits of the Baltic Ice Lake. Additionally, the map reveals previously undetected geomorphic features including (1) murtoos, (2) abundant traces of meltwater erosion manifested as channels and hummock corridors, (3) laterally extensive end-moraine systems (the Remmene and Kungslena icemargin positions) and (4) the distinct lobate shape of end moraines formed above the highest shoreline. This map provides a uniform base for future use in georesources, paleo ice-sheet modelling, geologic history, and geoconservation.

show abstract

Glacial dispersal and flow history, East Arm area of Great Slave Lake, NWT, Canada

Cited by 18 publications

References 63 publications

Regional stagnation of the western Keewatin ice sheet and the significance of meltwater corridors and eskers, northern Canada

Regional stagnation of the western Keewatin ice sheet and the significance of meltwater corridors and eskers, northern Canada

Hummock corridors in the south‐central sector of the Fennoscandian ice sheet, morphometry and pattern

Glacial geomorphology between Lake Vänern and Lake Vättern, southern Sweden

Contact Info

Product

Resources

About