Iceberg scouring and sea bed morphology on the eastern Weddell Sea shelf, Antarctica

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Abstract
A detailed shallow seismic and side scan sonar study, combined with vibrocoring on the continental shelf off Riiser Larsenisen ice shelf, East Antarctica, has provided information on the different morphological patterns present in the area. Features related to the motion of grounded icebergs prevail, with relatively narrow iceberg plough marks being predominant. A‘washboard pattern’probably results from a wobbling motion of grounded, tabular icebergs under influence of direct push by the advancing ice shelf, and a hummocky disturbed sea bed morphology results from small scale sediment slumping, often triggered by iceberg action. Narrow, elongate depressions incise the sea floor sediments, which are composed of glacigenic diamictons. Formation of the depressions is not fully understood, but erosion by subglacial meltwater under an expanded East Antarctic ice sheet is a possibility, although this requires a different glacier thermal regime than that of the present-day. Although this study is restricted in area, the processes of the region are typical of the Antarctic continental shelf. The results may hence have a more regional significance.