Linear scour depressions observed along the upper slope offshore of South Carolina are among the largest and most extensive iceberg ploughmarks found at subtropical latitudes. These features record the drifting of large, tabular icebergs south from the Laurentide Ice Sheet (LIS), along the entire length of US Atlantic margin during the last deglaciation (Hill et al. 2008).
Description
Over 400 individual, kilometre-length-scale furrows are observed in swath bathymetry along the upper slope (170–380 m water depth) of the southern US Atlantic margin (Fig. 1). The furrows are present along the entire continental slope from Cape Hatteras (c. 35° N) to the Florida Straits (c. 24.5° N), but are most prominent and well documented along a shoaling platform offshore of South Carolina (c. 32.5° N; Hill & Condron 2014). The furrows in this region are orientated predominantly WSW, sub-parallel to regional bathymetric contours (Fig. 1c). While some larger furrows are up to 400 m wide and 20 m deep, the scoured troughs are generally 10–100 m wide and <10 m deep (Fig. 1a, e). The furrows range from linear to arcuate with numerous cross-cutting tracks, particularly in deeper water where the ploughmarks are more densely spaced. Several of the more prominent linear furrows are traceable for more than 30 km along the margin. Many of …
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