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

• Main Authors: Sharpe, David, Lesemann, Jerome, Knight, Ross, Kjarsgaard, Bruce
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: University of Toronto 2021
• Subjects: Canada; Ice Sheet; Keewatin
• Online Access: http://hdl.handle.net/1807/107271; http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2020-0136

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. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.