M'Clure Strait in the Canadian Beaufort Sea (Fig. 1) is one of the largest cross-shelf troughs in the High Arctic, with a length of over 1000 km and a maximum cross-trough width of about 250 km (Batchelor & Dowdeswell 2014). It is thought to be the former location of a fast-flowing ice stream which drained the northwestern Laurentide Ice Sheet during the Late Wisconsinan, and probably a number of earlier Quaternary full-glacial periods (Stokes et al. 2006, 2009; Niessen et al. 2010; Batchelor et al. 2013). The Late Wisconsinan ice stream in M'Clure Strait is interpreted to have extended to the shelf break between 21–16 ka before undergoing rapid retreat (Stokes et al. 2009). Low rates of postglacial sedimentation have led to the preservation of an unusual assemblage of cross-cutting glacigenic landforms on the seafloor of outermost M'Clure Strait (Fig. 1).
(a) Swath bathymetry of the outer shelf of M'Clure Strait, Arctic Canada, superimposed on IBCAO v. 3.0 bathymetry (5 m contours). Multibeam acquisition system Kongsberg EM302. Frequency 30 kHz. Grid-cell size 10 m. Dashed line D indicates that the linear ridge-and-groove structures are probably continuous either side of the data gap. (b) Location of the study area (red box; map from IBCAO v. 3.0). MS, M'Clure Strait. (c) Schematic diagram showing the interpreted distribution of submarine landforms on the seafloor of M'Clure Strait which is described in the text. The probable direction of former ice flow is shown by a black arrow.
Description
The outer-shelf of M'Clure Strait contains several sets of landforms: linear ridge-and-groove structures, sinuous ridges, a wide trough-parallel ridge and three types of linear to curvilinear depressions. Multibeam imagery of the landforms is shown in Figure 1, together with a map of their distribution. Linear ridge-and-groove structures have an east–west orientation, parallel …
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