Geomorphology of the South Sandwich Trench: escarpments, seamounts and deeps

The Five Deeps Expedition acquired multibeam bathymetry data in the South Sandwich Trench using a latest-generation, full-ocean depth, Kongsberg EM124 multibeam echosounder. Prior to this fieldwork campaign, little high-resolution bathymetric data were available to underpin a range of marine biodiversity and geodiversity research for better-informed management of the deepest reaches of the South Georgia and South Sandwich Islands Marine Protected Area. The resulting map, covering a ~15,000 km2 area, is based on a combination of semi-automated techniques and expert interpretation of geomorphological features. This work presents the first detailed mapping of the South Sandwich Trench, revealing previously known seamounts and ridge complexes, sedimentary basins, and prevalent step-like escarpments. Smaller scale terraces and submarine landslide scars have also been mapped in detail. Geological and geomorphological interpretation and map production was funded by a grant awarded through the Darwin Initiative funded by the UK Government: Hadal Zones of our Overseas Territories (DPLUS093). doi: 10.13140/RG.2.2.31975.27048