Iceberg Scours

Researchers from the Center for Marine and Wetland Studies at Coastal Carolina University, South Carolina Department of Natural Resources and Scripps Institution of Oceanography have discovered evidence of iceberg scouring along the upper slope of the continental margin, approximately 70 miles offshore of Georgetown, South Carolina. The iceberg keel marks were found along a hardground platform surrounding a popular offshore fishing area known as the Georgetown Hole.

High resolution swath bathymetry data collected as part of the NOAA Ocean Explorations program in 2006 and 2007 show evidence of numerous furrows, 10−100 m wide and <10 m deep, oriented WSW along regional bathymetric contours. Piles of upturned blocks and boulders along the length of the furrows suggest the plowing of iceberg keels along the seafloor. Many of the furrows terminate in semicircular pits ringed by several meters high ridges. These are interpreted as terminal grounding pits, indicating icebergs have come to rest on the seafloor. The location and orientation of the keel marks suggests icebergs were entrained a southwestward flowing coastal current, most likely during the last glaciation. This may be the first evidence of iceberg transport to subtropical latitudes in the north Atlantic.

This research was presented at the 2007 Fall Meeting of the American Geophysical Union and appeared in the June 2008 issue of the journal GEOLOGY.

Publications

Hill, J.C.,  Gayes, P.T., Driscoll, N.W., Johnstone, E.A., and Sedberry, G, 2008, Iceberg scours along the southern U.S. Atlantic margin. Geology, v.36, no. 6, p 447-450.