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  • 1
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    Geological Society
    In:  In: Atlas of submarine glacial landforms. , ed. by Dowdeswell, J. A., Canals, M., Jakobsson, M., Todd, B. J., Dowdeswell, E. K. and Hogan, K. A. Geological Society London Memoirs, 46 . Geological Society, London, pp. 17-40.
    Publication Date: 2017-02-14
    Description: The mapping of submarine glacial landforms is largely dependent on marine geophysical survey methods capable of imaging the seafloor and sub-bottom through the water column. Full global coverage of seafloor mapping, equivalent to that which exists for the Earth's land surface, has, to date, only been achieved by deriving bathymetry from radar altimeters on satellites such as GeoSat and ERS-1 (Smith & Sandwell 1997). The horizontal resolution is limited by the footprint of the satellite sensors and the need to average out local wave and wind effects, resulting in a cell size of about 15 km (Sandwell et al. 2001). A further problem in high latitudes is that the altimeter data are extensively contaminated by the presence of sea ice, which degrades the derived bathymetry (McAdoo & Laxon 1997). Consequently, the satellite altimeter method alone is not suitable for mapping submarine glacial landforms, given that their morphological characterization usually requires a much finer level of detail. Acoustic mapping methods based on marine echo-sounding principles are currently the most widely used techniques for mapping submarine glacial landforms because they are capable of mapping at a much higher resolution.
    Type: Book chapter , NonPeerReviewed
    Format: text
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  • 2
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    Unknown
    Geological Society
    In:  In: Atlas of submarine glacial landforms. , ed. by Dowdeswell, J. A., Canals, M., Jakobsson, M., Todd, B. J., Dowdeswell, E. K. and Hogan, K. A. Geological Society London Memoirs, 46 . Geological Society, London, pp. 519-552.
    Publication Date: 2017-03-10
    Description: Glacimarine processes affect about 20% of the global ocean today, and this area expanded considerably under cyclical full-glacial conditions during the Quaternary (Fig. 1) (Dowdeswell et al. 2016b). Many of the submarine landforms produced at the base and margin of past ice sheets remain well preserved on the seafloor in fjords and on high-latitude continental shelves after the retreat of the ice that produced them. These glacial landforms, protected from subaerial erosion and beneath wave-base and tidal currents in water that is often hundreds of metres deep, are gradually buried by both hemipelagic and glacimarine sedimentation; they may be preserved over long periods in the geological record if palaeo-continental shelves are not reworked by subsequent glacier advances or bottom currents (Dowdeswell et al. 2007). This means that, first, submarine glacial landforms can be observed at or close to the modern seafloor after retreat of the last great ice sheets from their most recent Quaternary maximum about 18–20 000 years ago using swath-bathymetric mapping systems and, secondly, buried glacial landforms may also be identified and examined within glacial-sedimentary sequences from Quaternary and earlier ice ages using seismic-reflection methods.
    Type: Book chapter , NonPeerReviewed
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  • 3
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    Unknown
    Geological Society
    In:  In: Atlas of submarine glacial landforms. , ed. by Dowdeswell, J. A., Canals, M., Jakobsson, M., Todd, B. J., Dowdeswell, E. K. and Hogan, K. A. Geological Society London Memoirs, 46 . Geological Society, London, pp. 3-14.
    Publication Date: 2020-08-03
    Description: Glacial landforms and sediments exposed sub-aerially have been the subject of description, analysis and interpretation for more than a century (e.g. De Laski 1864; De Geer 1889). Indeed, such features provided important initial observations informing Louis Agassiz's ideas that ice was a key instrument in sculpting the landscape and that glaciers and ice sheets had extended to mid-latitudes during the past, implying that Earth's climate must have changed considerably through time (Agassiz 1840). It is only in the last few decades that attention has begun to focus on the marine evidence for the past growth and decay of ice sheets that is recorded in submarine landforms and sediments preserved on high-latitude continental margins. This interest has been driven, in part, by the recognition that sediments deposited below wave-base are often well preserved in the Quaternary geological record, and may be less subject to erosion and reworking than their terrestrial counterparts. In addition, new marine-geophysical technologies have enabled increasingly high-resolution imaging and penetration of the high-latitude seafloor, most notably using multibeam swath-bathymetric and three-dimensional (3D) seismic-reflection methods, and modern ice-strengthened and ice-breaking research vessels have allowed the effective deployment of these increasingly sophisticated instruments in the often ice-infested waters of the Arctic and Antarctic seas.
    Type: Book chapter , NonPeerReviewed
    Format: text
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