ICELANDIA

Continental crust and lithosphere is more widely distributed in the oceans than generally assumed. It may comprise blocks of full-thickness continental lithosphere or extended, magma-inflated continental layers that form hybrid continental/oceanic lithosphere. We propose a new, sunken continent beneath the North Atlantic Ocean that we name Icelandia. It underlies the Greenland-Iceland-Faroe Ridge and the Jan Mayen Microplate Complex, covering an area of ~ 600,000 km². It is contiguous with the Faroe Plateau and known parts of the submarine continental rifted margin offshore Britain. If these are included to form a “Greater Icelandia” the entire area is ~ 1,000,000 km² in size. The existence of Icelandia needs to be tested. Candidate approaches include magnetotelluric surveying in Iceland, ultra-long, entire-crust-penetrating reflection profiling along the length of the Greenland-Iceland-Faroe Ridge, dating zircons collected in Iceland, deep drilling, and re-appraising the geology of Iceland. Some of these methods could be applied to other candidate sunken continents.