Scientific highlights
Multibeam data from Pine Island Bay reveal imprints of the past extent and dynamics of Pine Island Glacier, one of the largest outlet glaciers draining the West Antarctic Ice Sheet. The seafloor morphology is characterized by large elongated groves that resemble so called mega-scale glacial lineations typically formed underneath fast flowing ice streams. These groves end in ridges, here referred to as “iceberg plow ridges”, comprised of material from the seafloor pushed in front of the grounded ice.
There is a well-developed grounding zone wedges visible in the multibeam bathymetry, formed where the grounded ice margin was stable for some time. The groves are in several places characterized by small regular corrugations, interpreted to have been formed in the trail of an armada of mega sized icebergs as tides moved the ice icebergs up and down in a regular pace. The mega sized icebergs were formed when the entire ice stream broke-up in the outer Pine Island Bay.
The interpretation from the combined sets of glacial landforms revealed from the multibeam bathymetry suggests that the Pine Island Ice Stream rapidly (<1 year) broke up and disintegrated during the deglaciation sometime prior to 12,000 years ago.
Citation
Björn Eriksson, Nina Kirchner, Frank Nitsche, Rezwan Mohammad, Richard Gyllencreutz (2021) High-resolution bathymetry data from expedition OSO, Southern Ocean, 2010. Dataset version 1. Bolin Centre Database. https://doi.org/10.17043/oden-oso-2010-bathymetry-1
References
Jakobsson M, Anderson JB, Nitsche FO, Dowdeswell JA, Gyllencreutz R, Kirchner N, O’Regan MA, Alley RB, Anandakrishnan S, Mohammad R, Eriksson B, Fernandez R, Kirshner A, Minzoni R, Stolldorf T, Majewski W (2011) Geological record of Ice Shelf Breakup and Grounding Line Retreat, Pine Island Bay, West Antarctica. Geology 39:691 – 694. https://doi.org/10.1130/G32153.1
Jakobsson M, Anderson JB, Nitsche FO, Gyllencreutz R, Kirshner AE, Kirchner N, O'Regan M, Mohammad R, Eriksson B (2012) Ice sheet retreat dynamics inferred from glacial morphology of the central Pine Island Bay Trough, West Antarctica. Quaternary Science Reviews 38:1 – 10. https://doi.org/10.1016/j.quascirev.2011.12.017
Graham AGC, Jakobsson M, Nitsche FO, Larter RD, Anderson JB, Hillenbrand C-D, Gohl K, Klages JP, Smith JA, Jenkins A (2016) Submarine glacial-landform distribution across the West Antarctic margin, from grounding line to slope: the Pine Island–Thwaites ice-stream system. Geological Society, London, Memoirs 46, 493 – 500. https://doi.org/10.1144/M46.173
Wise MG, Dowdeswell JA, Jakobsson M, Larter RD (2017) Evidence of marine ice-cliff instability in Pine Island Bay from iceberg-keel plough marks. Nature 550:506 – 510. https://doi.org/10.1038/nature24458
Data
Data description
The bathymetric data are provided as processed grids, divided into survey areas, with a grid cell size of 15 – 100 m. The grids are provided both in polar stereographic projection (Antarctic Polar Stereographic, EPSG 3031, true scale at 71° south) and in geographic coordinates (WGS 84, latitude and longitude). The horizontal datum is WGS 84 and the vertical datum is instantaneous sea level, implying that the vertical level has not been corrected for tides. For each projection, the bathymetric data grids are available in four formats: GeoTiff, netCDF, ASCII XYZ and ESRI Arc ASCII grid. Data are also illustrated as JPEG images.
Comments
The data were acquired in austral summer 2009/10 from Swedish icebreaker (IB) Oden during the OSO 2009/10 expedition. A Kongsberg EM122 1° × 1°, 12 kHz, multibeam echo-sounder was hull-mounted in IB Oden. Position, heading and attitude data were received from a Kongsberg-Seatex Seapath 320 navigation unit (GPS and GLONASS) with attached MRU5 motion sensor. The exact speed of sound at the multibeam transducers was provided by a Valeport Mini SVS/T sound speed and temperature sensor mounted in the sea-chest in Oden’s hull, close to the multibeam transducer arrays. This was interfaced with the multibeam system directly. In addition, sound speed profiles for the entire water column were provided by CTD (Conductivity, Temperature, Depth) stations as well as XBT (Expendable Bathy Thermograph) probes.
The data were collected in a mixture of sea-ice conditions, ranging from 5/10 to 8/10 coverage. Navigation was provided by a Seatex Seapath 320 without local augmentation as this is not available in the area. Sound speed correction was done regularly using data from a Seabird 911+ CTD (conductivity, temperature depth) or Valeport SVP (sound velocity profiler).
The OSO 2009/10 expedition started in McMurdo Station, Antarctica, and ended in Punta Arenas, Chile, and lasted from February 8 to March 12, 2010. IB Oden was chartered by the US National Science Foundation (NSF) to break an ice channel to the McMurdo station on the Ross Sea, to enable researchers to conduct trans-disciplinary studies in the Antarctic region. On the voyage back to South America, the icebreaker served as a research platform for the OSO expedition.
Contact information
Email address
[javascript protected email address]Phone number
+46-8-164719
Postal address
Martin Jakobsson
Department of Geological Sciences
Stockholm University
SE-106 91 Stockholm
Sweden
GCMD science keywords
Earth science > Oceans > Bathymetry/seafloor topography > Bathymetry
GCMD location
Ocean > Southern Ocean
Status
Completed
Dataset language
English
Project
Oden Southern Ocean (OSO) 2009/10 expedition
Publisher
Bolin Centre Database
Begin date
2010-02-08
End date
2010-03-12
Dataset version
1
DOI
10.17043/oden-oso-2010-bathymetry-1
Published
2021-11-04 15:12:41