Also known as Majuán Bank, Spartel Bank was once an island located in the Strait of Gibraltar at 35°55'N 5°58'W near Cape Spartel.
Currently it's highest point is 56 meters below sea level. Spartel Bank was flooded approximately 12,000 to 14,000 years ago due to rising sea levels at the end of the last Glacial Maximum.
Two hypotheses suggest Spartel Bank as the location of Atlantis.
In 2001 French geologist Jacques Collina-Girard noted that during the most recent Glacial Maximum of the Ice Age sea level was 135m below its current level. Coastlines were therefore different, and landmasses once existed that are now sunk. The Gibraltar Strait was narrower, creating a small semi-enclosed sea measuring 70km by 20km between the Mediterranean Sea and Atlantic Ocean. Spartel Bank formed an archipelago within this small sea with the largest island measuring about 10 to 12 kilometers across.
With rising ocean levels the island began to slowly shrink, until around 9400 BCE (11,400 years ago) there was an accelerated sea level rise of 4 meters per century known as Meltwater Pulse 1A, which drowned the top of the main island. A possible magnitude 9 earthquake proposed by marine geographer Marc-Andrè Gutscher as occurring in this region at about this time may have contributed to this relatively sudden disappearance by generating tsunamis. Collina-Girard proposes that the disappearance of this island was recorded in prehistoric Egyptian tradition for 5,000 years until it was written down by the first Egyptian scribes around 3000–4000 BCE, and the story then subsequently inspired Plato to write a fictionalized version interpreted to illustrate his own principles.
The lesser-known hypothesis was first published by Spanish-Cuban investigator Georgeos Díaz-Montexano in an April 2000 issue of Spanish magazine Más Allá de la Ciencia (Beyond Science), and later in August 2001 issues of Spanish magazines El Museo (The Museum) and Año Cero (Year Zero).
The origin of Collina-Girard's hypothesis is disputed, with Díaz-Montexano claiming it as plagiarism of his own earlier hypothesis, and Collina-Girard denying any plagiarism. Both individuals claim the other's hypothesis is pseudoscience.
In 2005, geophysicist Marc-André Gutscher examined the geological evidence at the site with interesting results: an unusually large earthquake and tsunami did hit this area in the time period referenced by Plato.
Numerous geographical similarities exist between Plato's descriptions of Atlantis and a paleoisland (Spartel) in the western Straits of Gibraltar. The dialogues recount a catastrophic event that submerged the island ca. 11.6 ka in a single day and night, due to violent earthquakes and floods. This sudden destruction is consistent with a great earthquake (M > 8.5) and tsunami, as in the Gulf of Cadiz region in 1755 when tsunami run-up heights reached 10 m. Great earthquakes (M 8–9) and tsunamis occur in the Gulf of Cadiz with a repeat time of 1.5–2 k.y., according to the sedimentary record. An unusually thick turbidite dated as ca. 12 ka may coincide with the destructive event in Plato's account. The detailed morphology of Spartel paleoisland, as determined from recently acquired high-resolution bathymetric data, is reported here. The viability of human habitation on this paleoisland ca. 11.6 ka is discussed on the basis of a new bathymetric map.
Later in 2005, after attending the Milos Atlantis conference, Gutscher clarified his position in that the area was above sea level and could have supported a fishing community, but nothing on the scale that Plato describes.
Currently no archaeology has been undertaken in the area. There is currently no evidence that Spartel Bank was ever inhabited.
http://usuarios.lycos.es/atlantisiberia/release_news.htm (offline 8/1/2016)
Collina-Girard, J. "Atlantis off the Gibraltar Strait? Myth and geology Comptes," Rendus de l'Académie des Sciences de Paris, Sciences de la Terre et des Planètes. 333, 2001, pp. 233-240.
Díaz-Montexano, Georgeos. Dossier: La Atlántida en España. Huellas Atlantes en la Península Ibérica. ¿La Atlántida de Platón? Revista '.. nº 134 (Mar/Apri-2000) 20-31
Gutscher, Marc-André. "Destruction of Atlantis by a great earthquake and tsunami? A geological analysis of the Spartel Bank hypothesis," in Geology Vol. 33, No. 8, 2005, pp. 685–688.
Ornelas, Genevra. "Atlantis Rises Again"," Science 722 (1), July 2005.
Parker, Bruce. The Power of the Sea. New York: MacMillan, 2012, pp. 138 & 139.