When underwater divers discovered what looked like paved floors, courtyards and colonnades, they thought they had found the ruins of a long-forgotten civilisation that perished when tidal waves hit the shores of a Greek island, Zakynthos.
But what was thought to be an underwater, lost city is actually a naturally occurring geological phenomenon. This ‘city’ was in fact created by a naturally occurring phenomenon up to five million years ago as revealed by a new research.
Archaeologists with the Ephorate of Underwater Antiquities of Greece found no further evidence that this was indeed an ancient civilisation. Suspecting a geological explanation, the Greek Ministry brought in researchers from the University of East Anglia and the University of Athens to investigate the structures.
“The site was discovered by snorkelers and first thought to be an ancient city port, lost to the sea,” said author Julian Andrews, a professor at UEA’s School of Environmental Sciences.
Using microscopy, X-ray techniques and chemical analyses, the researchers studied the mineral content of the underwater formations.
These analyses showed that the “ruins” are likely the fossilised remains of a natural plumbing system, located beneath the seafloor, for ancient hydrocarbon seeps. Here, methane and other hydrocarbons escape from the seafloor into the water above.
While beneath the seafloor, microbes in the sediment would have used the carbon in methane as fuel, forming a natural cement around the structures. The resulting structures are known to geologists as concretion.
Erosion then exposed the underground structures to the bustling ecosystem in the modern, shallow sub-tidal zone, where the structures were “encrusted by modern marine organisms,” Andrews and colleagues stated.
Original article on http://www.livescience.com/54965-zakynthos-underwater-city-formed-by-geology.html