Atlantis: Was it Geologically Possible?

by Rod Martin, Jr.

The story of Atlantis has been fascinating us for the last 2,300 years. Many have debated its meaning and existence. In another article, I wrote about scientific proof that something very, very big occurred the year Plato's mythical island empire was swallowed by the sea. That by itself is exciting, but it does not prove Atlantis existed. In any serious discussion of this legend, the subject of geology is at the core. Without a reasonable explanation for how Atlantis was geologically possible, any argument for the past reality of that lost island is weak at best.

Geology 101

Modern geology includes the subject of plate tectonics. The Earth is divided into more than a dozen such plates — several large ones and many smaller ones. These plates are not perfectly rigid, homogenous material. They are fractured, broken, split and buckling from the forces of movement against each other. At the boundaries of these plates, actions can be,

• Transverse — sliding past each other
• Convergent — moving toward each other
• Divergent — moving away from each other.

Plate boundaries are prone to earthquakes and volcanic activity. Most of the world's mountains are formed near plate boundaries, caused by plate convergence forcing the buckling of the Earth's crust, or an action known as "subduction" and the subsequent formation of volcanoes. This folded or buckled crust becomes many of the mountains. Examples include the Andes of South America, the Alps of Europe and the Himalayas of Asia. Subduction is merely the action of one plate attempting to slide underneath another. The action of billions of tons of rock rubbing against billions of tons of other rock creates lots of friction. Crustal folding is the result of this friction. This friction is, in effect, resistance to the movement of the plates against each other. And that resistance is converted into mountains.

Atlantis: Location

There have been numerous locations picked for Atlantis, from Sweden to Indonesia. Nearly all of them are wrong. Plato was quite clear on the location. All of the others are, by definition, not Atlantis. According to Timaeus and Critias, the two dialogues which are the source of the Atlantis story, the lost island was beyond the Strait of Gibraltar, in the Atlantic Ocean. The nearest portion of Atlantis was facing a region in Southwestern Spain called Gadira. This is the region surrounding modern Cádiz (Phoenician Gadir, Roman Gades and Moorish Qādis). Most claimants ignore this very specific detail from Critias.

Movement of the Africa Plate

Two hundred million years ago, Africa was nestled against the eastern coastline of South America. The bulk of Eurasia was far to the North, across the Tethys Sea. Over millions of years, Africa rotated away from South America, forming the South Atlantic and closing the Western Tethys to become the Mediterranean. The North Atlantic had already begun opening a few million years earlier between North America and Eurasia.

At some point in the last hundred million years, Africa and Eurasia were moving together away from the Americas. The mid-Atlantic Ridge (a largely divergent boundary) was creating new oceanic crust, adding new material to the plates on either side. An animation of plate movement for the last 240 million years, supplied by the United States Geological Service, shows that Africa moved northward toward Eurasia, finally closing the Mediterranean in the East.

Atlantis: Geological Hypothesis

Atlantis, if it existed, would have been the result of crustal folding as the Africa plate attempted to subduct underneath the Eurasian in the North Atlantic. The northward movement of the Africa plate created a subduction zone all across its border with the Eurasian plate. Approximately 50 million years ago, something caused damage to the plate boundary in the vicinity of what is now the Azores underwater plateau. This damage created an impediment to subduction locally. All northward movement by the Africa plate, here, was converted into crustal folding.

Several million years later, according to R. Searle (1980, "Earth and Planetary Science Letters," v. 51, p. 415–434), a new divergent boundary was created. The mutual boundary between Africa and Eurasia is largely east-west in direction. This new stretch of boundary, called the Terceira Ridge, is toward the Northwest. Something happened. The Africa plate started moving in a different direction.

This Terceira Ridge in the West is a divergent boundary (also called a "spreading center," like the mid-Atlantic Ridge). Farther east before Gibraltar, the boundary is currently only slightly and intermittently convergent. Beyond Gibraltar, in the Mediterranean, the boundary becomes heavily convergent. The pattern is clear. The Africa plate is rotating away from Eurasia in the West, and toward it in the East. But why?

Approximately 36 million years ago, the Africa plate could no longer push against the area of boundary damage. The mountains created there had poked above the ocean surface, creating an island. With an immovable barrier at the new Atlantis, but with continued subduction farther east, the only result would be one of rotation — deflected around the impediment. With this new pattern of plate movement, the linear support of the new mountains was withdrawn. The new angular motion around the area of boundary damage gradually would have weakened those mountains, causing the island to break up over the next several million years.

There is much more to this geological tale. Much of the evidence cannot be included in this short article. Briefly, the damage was not confined to the area of Atlantis, but created stresses across North Africa, breaking off a portion of the plate, creating the new Arabia plate, and forming the Great Rift Valley, still in the process of formation today. Millions of years after the new rotation had started, the damage had crept along the plate boundary toward Gibraltar and resulted in its eventual closure. For nearly a million years, the Mediterranean was cut off from the oceans of the world and dried up. This was the Messinian Salinity Crisis — 5.9–5.3 million years ago. And for awhile, Atlantis was a peninsula of Europe and Africa.

I had always wondered how Plato's Atlantis got its elephants. For 600,000 years, elephants from Europe and Africa could merely walk across to that fabled land.

Atlantis had its effects on the geology of Earth, and also on its climate. But there are also clues that the children of Atlantis — its refugees — may have been matriarchal (ruled by women). From this we may have gotten the myths of the Amazons and the patterns of many cultures across Eurasia and North America. These, however, are the subject of another article.