Amundsen Basin Amundsen Basin The Amundsen Basin, with depths up to 4.4 km, is the deepest abyssal plain in the Arctic Ocean. The Amundsen Basin is embraced by the Lomonosov Ridge (from to ) and the Gakkel Ridge (from to ). It is named after the polar researcher Roald Amundsen. Together with the Nansen Basin, the Amundsen Basin is often summarized as Eurasian Basin. The Russian-American cooperation Nansen and Amundsen Basin Observational System (NABOS) aims "to provide a quantitative observationally based assessment of circulation, water mass transformations, and transformation mechanisms in the Eurasian and Canadian Basins of the Arctic Ocean". The Amundsen
Welsh Basin Welsh Basin The Welsh Basin was a northeast-southwest aligned back-arc depositional basin during the Cambrian, Ordovician and Silurian periods during which a considerable thickness of marine sediments was laid down in the area. To the southeast lay the Midland Platform (a part of the micro-continent of Avalonia) and to the northwest, within the Iapetus Ocean, through what is now Ireland and the Lake District, was an island arc; a northeast-southwest aligned Irish Sea landmass which was associated with volcanic activity. Examination of the sediments and associated fossils allows the deeper centre of the basin to be distinguished from shallower 'platform'