Glacial geomorphology of the northern Kivalliq region, Nunavut, Canada, with an emphasis on meltwater drainage systems

Abstract

This paper presents a glacial geomorphological map of glacial lineations, ribbed terrain, moraines, meltwater channels (subglacial and ice-marginal/proglacial), eskers, glaciofluvial deposits, ice-contact outwash fans and deltas and abandoned shorelines on the bed of the former Laurentide Ice Sheet in northern Canada. Mapping was compiled from satellite imagery and digital elevation data and landforms were digitised directly into a Geographical Information System. The map reveals a complex glacial history characterised by multiple iceflow events, including fast-flowing ice streams. Moraines record a series of pauses or readvances during overall SE retreat towards the Keewatin Ice Divide. The distribution of subglacial meltwater landforms indicates that several distinctive scales and modes of drainage system operated beneath the retreating ice sheet. This includes a large (>100 km) integrated network of meltwater channels, eskers, ice-contact outwash fans and deltas and glaciofluvial deposits that originates at the northern edge of Aberdeen Lake. The map comprises zone 66 of the Canadian National Topographic System, which encompasses an area of 160,000 km 2 . It is presented at a scale of 1:500,000 and is designed to be printed at A0 size. ARTICLE HISTORY

Large-scale integrated subglacial drainage around the former Keewatin Ice Divide, Canada reveals interaction between distributed and channelised systems

“…St-Onge, 1984;Aylsworth and Shilts, 1989;Rampton, 2000;Utting et al, 2009;Sharpe 185 et al, 2017;Lewington et al, 2019) and meltwater channels (e.g. Storrar and Livingstone, 2017) have also been recorded. At a large scale, eskers radiate out from the ice divide, beneath which they are rare (Shilts et al, 1987;Aylsworth and Shilts, 1989;Storrar et al, 2013Storrar et al, , 2014a.…”

“…Clark and Walder, 1994;Brennand, 2000;Storrar et al 2013;Burke et al, 2015;Livingstone and Clark, 2016;Mäkinen et al, 2017) rather than as a holistic drainage signature (c.f. 155 Storrar and Livingstone, 2017). As such, it is not yet clear whether or how differing expressions of subglacial drainage are interrelated and to what extent variations in drainage and / or background conditions (e.g.…”

Glacial geomorphological mapping: A review of approaches and frameworks for best practice

“…glacial valleys, meltwater channels), as well as major glacial depositional landforms produced by larger ice masses (e.g. Greenwood and Clark, 2008;Heyman et al, 2008;Livingstone et al, 2008;Hughes et al, 2010;Morén et al, 2011;Barr and Clark, 2012;Stroeven et al, 2013;Turner et al, 2014a;Margold et al, 2015a;Blomdin et al, 2016a, b;Lindholm and Heyman, 2016;Mäkinen et al, 2017;Storrar and Livingstone, 2017). However, the recent development of UAV (see section 3.2.2.5) and LiDAR technologies have allowed the generation of very high resolution DEMs (<0.1 m), enabling the application of DEMs to map small glacial landforms (e.g.…”

“…First-and second-order DEM-derivatives, including surface gradient (slope) and curvature, have also been found to be useful for mapping (e.g. Smith and Clark, 2005;Evans, 2012;Storrar and Livingstone, 2017).…”

“…Geomorphological mapping using a combination of field mapping and remotely-sensed data interpretation (hereafter 'remote mapping'), or a number of remote sensing methods, permits a holistic approach to mapping, wherein the advantages of each method/dataset can be combined to produce an accurate map with robust genetic interpretations (e.g. Boston, 2012a, b;Darvill et al, 2014;Storrar and Livingstone, 2017). As such, approaches are required that allow the accurate transfer and assimilation of data from these various sources, particularly where data are transferred from analogue (e.g.…”