What Was the Lost Atlantic Island

In each of his Atlantis dialogues, Plato describes the size of the Atlantic Island. From the Timaeus“the (Atlantic) island was larger than Libya and Asia put together”. From the Critias“was an island greater in extent than Libya and Asia”.

In the time of Solon and Plato, “Libya” was a region of North Africa to the west of Egypt, while “Asia” was about half of modern-day Turkey. Those combined areas are about one million square kilometres, so Plato’s Atlantic Island was even larger. If the complete Atlantic Island were still above sea level, it would be the second-largest island on Earth, somewhere between the size of Greenland and New Guinea.

From Plato’s precise geographical descriptions of the location and size of his “Atlantic island”, it had to be located in the Caribbean region because no other site satisfies all of his exact details. Plato’s Caribbean Atlantis argues that the Atlantic Island was once a large landmass, which then “sank” and now forms a large part of the floor of the Caribbean Sea.

The Caribbean from Space
The Caribbean – North America at the top; Mesoamerica and South America on the left; the Greater and the Lesser Antilles on the right - Source: NASA

Plato’s Caribbean Atlantis suggests that the now submerged Beata and Aves Ridges and the Venezuelan Basin were uplifted in the extremely distant past and eventually emerged above sea level. These geological structures formed the complete Atlantic Island when they joined with the already emergent Caribbean islands of Hispaniola and Puerto Rico.

Sometime after 11,000 years ago, the Beata and Aves Ridges and the Venezuelan Basin submerged. The islands of Hispaniola and Puerto Rico are now the only remains of the once-great Atlantic Island.

The Caribbean Region - Source: Google Earth
Map of the Caribbean showing major named features - Source: Case, J.E., MacDonald, W.D. & Fox, PJ. 1990. Caribbean crustal provinces; seismic and gravity evidence: in Dengo, G. & Case, I.E. (eds), The Geology of North America, Volume H, The Caribbean Region, 15-36. Geological Society of America