In multibeam echosounder and subbottom profiler data acquired during R/V Polarstern cruise ARK-VII/3a from the Hovgaard Ridge (Fram Strait), we found evidence for very deep (>1200 m) iceberg scouring. Five elongated seafloor features have been detected that are interpreted to be iceberg scours. The scours are oriented in north-south/south-north direction and are about 15 m deep, 300 m wide, and 4 km long crossing the entire width of the ridge. They are attributed to multiple giant paleo-icebergs that most probably left the Arctic Ocean southward through Fram Strait. The huge keel depths are indicative of ice sheets extending into the Arctic Ocean being at least 1200 m thick at the calving front during glacial maxima. The deep St. Anna Trough or grounded ice observed at the East Siberian Continental Margin are likely source regions of these icebergs that delivered freshwater to the Nordic Seas.
Multibeam data were collected during R/V Polarstern cruise ARK-VII/3a. Data recording and systematic profiling was executed in Fram Strait and was supervised by five hydrographers. Data are unprocessed and may contain outliers and blunders. Therefore the data should not directly be used for grid calculations and charting projects but need to be edited furthermore. The dataset consists of 3 files in ATLAS ascii multibeam format including 'record control words' (*.dux) which are compressed with GZIP to size of 26.6 MB. Atlas DUX data files can be processed using the open source software package MB-System (http://www.ldeo.columbia.edu/res/pi/MB-System/). Values of depths and lateral distances are averaged with neighbouring beams. The file ark07_3a-hyd.tar.gz includes the bathymetry in AWI Hyd-format (hdl:10013/epic.37976) including not averaged depths and lateral distances. Contact mailto:infobathy@awi.de for data access.
Supplement to: Arndt, Jan Erik; Niessen, Frank; Jokat, Wilfried; Dorschel, Boris (2014): Deep water paleo-iceberg scouring on top of Hovgaard Ridge-Arctic Ocean. Geophysical Research Letters, 41(14), 5068-5074
