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Swath sonar bathymetry during POLARSTERN cruise ANT-XXII/5 (PS67) with links to multibeam raw data files

Authors
Publisher
PANGAEA
Publication Date
Identifiers
DOI: 10.1594/pangaea.680791
Keywords
  • Ant-Xxii/5
  • Awi_Paleo
  • Paleoenvironmental Reconstructions From Marine Sediments @ Awi
  • Polarstern
  • Ps67
  • Ps67/5-Track
  • Standard For Geospatial Metadata V
  • 2
  • Swath-Mapping System Atlas Hydrosweep Ds-2
  • Underway Cruise Track Measurements
  • Uniform Resource Locator/Link To Image
  • Uniform Resource Locator/Link To Metadata File
  • Uniform Resource Locator/Link To Raw Data File
Disciplines
  • Economics
  • Political Science

Abstract

larter_25505.indd GEOLOGY, May 2009 411 INTRODUCTION The Intergovernmental Panel on Climate Change (IPCC, 2007) has highlighted future changes in the dynamics of large ice sheets as the largest uncertainty in sea level–rise projec- tions. Understanding processes that control ice discharge is therefore of societal and economic importance. Ice discharge from the Antarctic and Greenland ice sheets occurs mainly through fast-fl owing ice streams (Bamber et al., 2007). Geophysical and drilling investigations of mech- anisms at ice-stream beds that enable streaming fl ow have been conducted over more than two decades (e.g., Alley et al., 1986; Engelhardt and Kamb, 1998; Smith et al., 2007), but have been limited by inaccessibility of fi eld sites and the diffi culty of investigating an interface buried beneath hundreds of meters of ice. Although investigating modern ice sheet beds is diffi cult, pristine subglacial bedforms from a formerly more extensive ice sheet are preserved in many deep troughs on the Antarctic continen- tal shelf, and large areas of the former ice base can be imaged using modern swath sonar tools (Pudsey et al., 1994; Canals et al., 2000; Wellner et al., 2001, 2006; Ó Cofaigh et al., 2002). Wellner et al. (2001) described a typical progression of bedform types along paleo–ice fl ow paths, from grooves, roches moutonnées, and subglacial meltwater channels on the inner shelf, through a zone of drumlins associated with a transition from crystalline to sedimen- tary substrates, to mega-scale glacial lineations on the outer shelf. Furthermore, Wellner et al. (2001, 2006) interpreted this progression of bedform types as being associated with accel- erating ice fl ow rates, with the zone of drumlins marking the onset of streaming fl ow. Ó Cofaigh et al. (2002) showed that extensive multibeam swath bathymetry data collected along Margue- rite trough, Antarctic Peninsula, was generally consistent with this model. Here we present new multibe

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