Submarine mass wasting on the Crary Fan, Antarctica

• Main Authors: Gales, J. A., Larter, R. D., Leat, P.T., Long, Dave, Jokat, Wilfried
• Format: Conference Object
• Language: unknown
• Published: 2015
• Subjects: Antarctic; The Antarctic; Weddell Sea; Weddell; Antarc*; Antarctica
• Online Access: https://epic.awi.de/id/eprint/36827/; https://hdl.handle.net/10013/epic.44582

Multibeam data from the southern Weddell Sea, Antarctica show three submarine slides on the upper slope of the Crary Fan, a large Trough Mouth Fan offshore from the glacially calved Filchner cross-shelf trough. These slides are the first Quaternary examples to be documented on an Antarctic Trough Mouth Fan and provide evidence for rarely observed submarine mass wasting on the Antarctic continental margin. Their occurrence contrasts many other previously glaciated continental margins, where mass wasting is common. All submarine slides head at the shelf edge (~500 m water depth), with two styles of mass wasting observed. The first style is characterised by a complex and wide (~20 km long) headwall, with a relief of 60 m and coverage of ~800 km2. Large, tabular slabs are observed down slope of the headwall. Two slides follow the second style of mass wasting. This style is characterised by a small, narrow and steep scarp at the shelf edge with increasing slide width (maximum 6 km) down slope. No large sediment deposits or lobes are observed down slope of these slides, although this may be limited by data extent. The large-scale differences in slide occurrence along the Antarctic continental margin suggest a significant variation in slope and sedimentary processes, environmental characteristics and/or glacial dynamics. It is likely that the slides are influenced by failure of weak layers within the subsurface, which may have been affected by rapid sediment transport and mass flow generation at the shelf edge, as indicated by widespread debris flow deposits observed in subbottom profiler data on the Crary Fan.