Seabed images and substrata of the southern Lucky Strike hydrothermal vent field

Located on the Mid-Atlantic Ridge, Lucky Strike is a large basalt hosted hydrothermal vent field ranging from a depth of 1500 to 2000 m. Starting from 2010, the deployment of a deep-sea observatory aimed to investigating hydrothermal processes in that vent field. The yearly cruises MoMARSAT to maintain the observatory allowed to gather additional datasets. This particular one comprises four sets of non-overlapping images that were retrieved by a downward-looking camera (OTUS) mounted on the remotely operated vehicle Victor6000. The latter was flown at constant altitude (~ 4 m) and speed (~ 0.2 m/s) over parallel transects planned in four sites (Eiffel Tower, Montsegur, Sapins, White Castle) and around different active vent edifices in order to acquire seabed images for investigation of spatial patterns of the geology and of the biology. The seabed characteristics observable in images was categorised by labeling manually in Biigle (for Eiffel Tower, Montsegur and White Castle) or automatically (for Sapins with a deep-learning model trained and validated on the other sites). Categories considered for substratum classification were the shell/white fragment cover (0-10%; 10-50%; 50-100% of surface covered), the lithology (basalt; slab; sulphurs; volcanoclastic sediment) and the geomorphology (brecciated; fractured; marbled; sedimented; presence of scree rubbles). Annotations and .jpg images were georeferenced as .gpkg shapefiles and .geotiff images respectively.