Four years ago, scientists thought they had found the perfect place to settle the debate: a farmer's house, on a bluff overlooking the Black Sea, built about 7,500 years ago -- just before tidal waves inundated the homestead, submerged miles of coastline and turned the freshwater lake into a salty sea.
Some believed the rectangular site of stones and wood could help solve the age-old question of whether the Black Sea's flooding was the event recounted in the Biblical story of Noah.
That story tells of a calamitous flood occurring over 40 days and nights. Scientists had largely dismissed it, believing the Black Sea filled up gradually with gently rising waters. That wisdom was rocked, however, when two scholars claimed seven years ago that the Black Sea's flooding was more recent -- and so rapid and widespread that it forced people to move as far away as mainland Europe.
Scientists who in the summer of 2003 visited the underwater site off the northern Turkish coastal town of Sinop couldn't arrive at any conclusions. The settlement, about 330 feet underwater, was "contaminated" by wood that had drifted in, foiling any attempt to accurately date the ruin -- and thus date the flood.
"We were not able to get a smoking gun," said Robert Ballard, the underwater explorer and discoverer of the Titanic, who led the $5 million Black Sea expedition.
But the trip was successful, and the scientists are preparing to publish their findings early next year.
Ballard heralded the work of Hercules, an underwater excavator that was used for the first time. The 7-foot robot gingerly dug around the deep-water ruins and retrieved artifacts using pincers outfitted with sensors that regulated the pressure they exerted -- much like a human hand.
Fredrik Hiebert, an archaeology fellow at National Geographic, said the mechanical excavator's success ushers in a new era in ocean archaeology.
"We now have the technical capabilities to excavate scientifically in underwater environments," the former University of Pennsylvania professor said. "We've moved beyond the grab-and-look part of [underwater] archaeology."
The team also used high-definition cameras, a new Internet bandwidth and satellite hookups to link scientists and schoolchildren live to the mission -- the first time all such technologies had been employed simultaneously on an expedition.
On another leg of the journey, the explorers took a closer look at a 1,500-year-old trading vessel that they say is the best-preserved ship of the Byzantine period ever located.
Scientists were especially interested in this site, dubbed "Shipwreck D," because the Black Sea's unique, oxygen-less water leaves everything on the bottom mostly intact. Shipwreck D is so well-preserved that a cord tied in a V-shape at the top of the trading vessel's wooden mast is still clearly visible.
Researchers noted the ship's planks are coated with a substance believed to be wax, an indication the merchants were transporting honey, said Cheryl Ward, a maritime archaeologist at Florida State University who led the study of Shipwreck D and three other ship ruins nearby.
Hercules brought up six amphorae -- slender, carrot-shaped shipping jars -- from which the sediment will be analyzed for traces of pollen that would solidify the honey theory.
Ward thinks the ship could have been part of a transport fleet for a family-owned grocery store.
"These were like the 18-wheelers that hauled our food from production to market," Ward, 43, explained by telephone from an archaeological dig in Turkey.
She thinks the boat was one of hundreds plying the Black Sea in the 5th and 6th centuries in a frenetic outburst of commercial activity, as Rome ordered more taxes to be collected from its eastern provinces. The edict spawned a boom in local production and trading among communities across the Mediterranean and north to the Crimea.
"It was a very, very dynamic time," Ward said. "It's like the early '90s Silicon Valley takeoff [when] everyone had a lot of great ideas.
"It proves we're part of a longtime continuum of humanity," she added.
Ballard, 62, hoped he would draw a more definitive line to the Noah flood theory that the trip's main sponsor, National Geographic, had highlighted to spur public interest in the expedition.
Scholars agree the Black Sea flooded when rising world sea levels caused the Mediterranean to burst over land and fill the then-freshwater lake. The flood was so monstrous it raised water levels by 509 feet and submerged up to 58,000 square miles of land, an area about the size of the state of Georgia.
But scholars are divided on when the flood occurred, and how rapidly. Most believed it took place about 9,000 years ago and was gradual. But Columbia University marine geologists Walter Pitman and William Ryan wrote in 1997 that the flood was sudden and took place about 7,150 years ago. The scientists' conclusions reinvigorated the Noah flood debate.
Hiebert had hoped wood pieces from the suspected homestead would prove it was built before the flood, which would help date the event once and for all. But some of the retrieved pieces dated to after the flood, meaning no one can say exactly when the settlement had been built.
Also, scientists found nothing that could have established whether the site was a human settlement.
"We didn't find a farmer or his tools," Ballard said.
Still, scientists are puzzled why a ruin, then located on a 40-foot rise and at the mouth of a river, would be anything but an ancient, well-situated home. They don't understand how the debris floated in and settled around the site, especially considering there's no other similar pile of underwater matter for miles around.
Ballard ponders this in his office at the Institute for Exploration in Mystic, Conn., a four-foot-long amphora from the 1st century B.C. encased under the glass table where he sits. "We found the [ancient] shore. And we did find a hill. And we found a thing on top of the hill. Did we just not pick up the right thing?"