The Britannia Guyots (also known as Britannia Bank, Britannia Tablemount, Britannia Tablemounts, Brittania Guyots or Brittania Tablemounts) are a line of extinct volcanic seamounts in the Tasmantid Seamount Chain.
They are basaltic volcanoes that erupted between 17,600,000 and 20,800,000 years ago,[2] with survey data that indicates they rise about 4,000 m (13,000 ft) above the local sea floor to a minimum depth of 421 m (1,381 ft).[1] The sediments deposited on top of the alkali olivine basalt[2] originate from the early Middle Miocene when the ocean water was tropical to subtropical.[3] They were described as seamounts in 1961.[4]