Washington - Artefacts found at the bottom of the Black Sea provide new evidence that humans faced a great flood, perhaps that of the biblical Noah, thousands of years ago, the discoverers say.
Remnants of human habitation were found 900m underwater, about 19,2km off the coast of Turkey, undersea explorer Robert Ballard said on Tuesday.
"There's no doubt about it, it's an exciting discovery," Ballard said in a telephone interview from his research ship. "We realise the broad significance the discovery has and we're going to do our best to learn more."
Fredrik Hiebert, of the University of Pennsylvania, chief archaeologist for the Black Sea project, said from the ship: "This find represents the first concrete evidence for the occupation of the Black Sea coast prior to its flooding."
Many ancient Middle Eastern cultures have legends of a great flood, including the Bible story of Noah.
Columbia University researchers William Ryan and Walter Pittman speculated in their 1997 book Noah's Flood that when the European glaciers melted about 70 00 years ago, the Mediterranean Sea overflowed into what was then a smaller freshwater lake to create the Black Sea.
Last year, Ballard found indications of an ancient coastline kilometres off the current Black Sea coast. His new discovery provides evidence that people once lived in that region.
Ballard, a National Geographic Society explorer-in-residence, said he had studied shells found along the ancient coastline and found two types. One group is an extinct type of freshwater shell, while the second is from saltwater shellfish.
The saltwater shells date back 6 500 years, while the freshwater shells all date to 7 000 years ago and older.
"So, we know that there was a sudden and dramatic change from a freshwater lake to a saltwater sea 7 000 years ago," he said on Tuesday.
"And we know that as a result of that flood a vast amount of land went underwater.
"And we now know that that land was inhabited. What we don't know is who these people are, we don't know how broad their settlements were ... but we're expanding our studies to try to determine that."
Ballard said his team, using remote-controlled underwater vessels with cameras, located a former river valley beneath the sea and in that valley was a collapsed structure, including some preserved wooden beams that had been worked by hand.
The structure was "clearly built by humans", and was characteristic of stone-age structures built 7 000 years ago in the interior of Turkey, Ballard said.
It contained a stone chisel and two other stone tools with holes drilled through them, he said, adding that nothing had been removed from the site.
"When you first find a site you don't just run in there and start picking up things," he said.
The group is now mapping the site and looking for other structures in the area.
"This is a work in progress," Ballard said. "It is critical to know the exact era of the people who lived there, and to that end we hope to recover artifacts and wood for carbon dating so we can figure out what sort of people lived there and the nature of their tools."
The discovery was made within Turkey's coastal waters and that country's directorate of monuments and museums has a representative on the research vessel. - Sapa-AP