Washington, Feb 23 : Scientists say that the Black Sea didn't come into being following what is called as the "Noah''s Flood", but after something much more catastrophic that happened 9,500 years ago, leading to the formation of the only inland sea in the world.

The Black Sea, which is surrounded by Turkey, Georgia, Russia, Ukraine, Romania, and Bulgaria, was once a freshwater lake surrounded by rich and fertile plains.

However, about 9,500 years ago, sea levels rose as the climate warmed, and saltwater poured in from the Mediterranean through the Sea of Marmara.

One of the theories has suggested that a huge flood drowned the landscape, forcing some of the planet''s first farmers to move elsewhere.

"I would say there was never a big flood. What we showed was that it''s impossible," Discovery News quoted Liviu Giosan, a geologist at Woods Hole Oceanographic Institute in Cape Cod, Massachusetts, and lead author of the study, as saying.

However, the new work has instigated a debate about the geologic history of the Black Sea.

Fossil record has clearly showed a shift from freshwater to saltwater species around the time, but scientists are still not clear whether the change happened gradually or dramatically.

Soviet studies have not provided many details about the history of the region, but in the mid-1990s, a team led by Columbia University geologist William Ryan concluded that there had been a massive, catastrophic flood, which they dubbed "Noah''s Flood," but their theory has been controversial since then.

However, researchers in the new study, instead of looking underwater, drilled a 42-meter (140-foot) hole in the Danube delta -- a flat plain that has formed out of sediments deposited by the Danube River as it pours into the Black Sea.

By every layer, their core samples were found to go back more than 10,000 years, which enabled them to see what happened both before and after the flood.

By dating sediment layers as well as clam shells that were still closed shut, researchers determined that the Black Sea was 30 meters (98 feet) below present its level at the time of the flood, not 80 meters (262 feet) as Ryan''s team maintains.

Thus, the researchers suggested that the flood was much smaller than originally thought.

"It moves the balance of evidence from this being a big, catastrophic event to its not being such a big event," said oceanographer Mark Siddall, of the University of Bristol in the United Kingdom.

Giosan said that he had invited Ryan to join him in an effort to replicate and extend the results by drilling more cores in the Danube delta. (ANI)