| Summary: | ABSTRACT Each year in the Alaskan Beaufort Sea, shear and compressional forces within the seasonal sea-ice canopy cause the formation of ice keels which may contact the seafloor and become grounded. When a grounded ice keel plows through seafloor sediment it creates a furrow termed an ice gouge. Two tracklines in eastern Harrison Bay, Alaska, were resurveyed with precise navigation techniques each year between 1977 and 1982 using side-scan sonar and a high resolution fathometer in order to determine the yearly rate at which ice gouges are added to the seafloor. The observation and measurement of the number, size and distribution of ice gouges dated as less than one year old indicate that there is significant variability from year to year in the ice gouge process. The tracklines are divided into 1-km segments, each 250-m wide, in order to tabulate the data. It was found that an average of 8 to 9 new gouges are added to the seafloor each year in each 1-km segment; however, as many as 64 ice gouges can occur in a 1-km segment in any one year. The average depth of the newly formed gouges is calculated as 18-cm. Gouge depth frequency is described as a negative exponential distribution. The area of seafloor disrupted by ice gouging is considerable. Seafloor disruption averages 37-m/km/year with a maximum of 214-m of disruption occurring in a 1-km segment. Average height of the sediment ridges bounding the gouges is 14-cm with a maximum of 90-cm. The largest and deepest gouges generally occur in water depths deeper than 10-m. Between water depths of 5-to 18-m, the amount of area! disruption caused by new ice gouges increases with increasing water depth when unaffected by seafloor morphology such as shoals. Deep gouges may occur in all water depths if similarly unaffected by seafloor morphology . The area of seafloor disrupted each year by ice gouging ranges between 1 and 6 percent and averages 3.7 percent. The volume of sediment disrupted averages about 6000-m /km /year. Gouge orientations and terminations indicate ...
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