CGRG Bibliography of Canadian Geomorphology
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Author : Bennett, R.; Blasco, S.; and MacLean, B.
Date : 2007.
Title : Seabed features related to glacial ice dynamics in Amundsen Gulf.
Publication : CANQUA Ottawa 2007. Canadian Quaternary Association Conference, June 4-8, 2007. Carleton University, Ottawa, Ontario, Canada.
Issue :
Page(s) :
Abstract
Seabed features interpreted to be related to glacier ice and/or meltwater movement have been identified from multibeam echosounder data in Amundsen Gulf and Dolphin and Union Strait. This area was glaciated during the Late Wisconsinan by an ice stream from the Laurentide Ice Sheet with the low sedimentation rate in Amundsen Gulf leading a lack of sediment cover over these features. Glacial sole marks are widespread throughout Amundsen Gulf and Dolphin and Union Strait. The sole marks are linear, parallel ridges and troughs in about 400m water depth that are orientated in a northwest – southeast direction. The ridges are approximately 40 to 300m wide, 30m high, up to 5km long, and each individual ridge has a well defined lee and stoss side. Erosion is visible at the foot of the lee side of some of the ridges. It is not certain if these features originated from the movement of a large ice sheet or if they were created by sub-glacial meltwater processes. Similar features are observed onshore on nearby Wollaston Peninsula, Victoria Island. Ice scours with irregular paths and scour depths up to 3.6m deep have been observed to water depths of 410m in Amundsen Gulf. The ice scours are not observed to be present over the glacial sole marks. These scours are not active features as sea ice has only been observed to generate ice scours to water depths of only 60m. These scours could have been caused by large icebergs calved from the ice stream that was once present in the area. The current interpretation of these data in Amundsen Gulf is that the glacial sole marks were formed underneath a glacial ice stream during the last glaciation and the ice scours in ~410m water depth were formed by icebergs that calved from the ice stream. Some theories have been put forward that suggest that Amundsen Gulf was the site of an ice stream which extended out over the Beaufort Shelf break and even to the Chukchi Shelf in Russia. Seabed evidence from multibeam and sub-bottom data suggests that the Amundsen Gulf ice stream did not extended past Banks Island. The ice stream extent as defined by the seabed glacial features supports the Deglaciation of North America maps by Dyke et al. 2003. Glacial sole marks have also been observed by multibeam data in Peel Sound, Viscount Melville Sound, Lancaster Sound, and Pond Inlet.
Bibliography of Canadian Geomorphology