Visiting scientist explores science behind Noah's flood

5/3/2005 5:55:14 AM

A torrent of water about 200 times as powerful as Niagara Falls was likely the cause of the great flood depicted in the bible and the story Gilgamesh, said a visiting researcher from Columbia University.

Schaible Auditorium was packed last Tuesday night for Walter C. Pitman's lecture "Noah's Flood: Myth or Reality?" He explained how a catastrophic geological event became the plot line for several of our culture's most prevalent legends.

Pitman, of the Lamont-Doherty Earth Observatory at Columbia, said that the legend exists because large, populated areas of ancient Mesopotamia around the Black Sea were flooded as a result of rising global sea levels.

Prior to the flood, the Black Sea was a flow-through basin, with water coming from the mountains in the north, Pitman said. As the glaciers that fed the Black Sea melted away, the water shifted course away from the Black Sea and toward the Baltic Sea or Arctic Ocean. A dry period in the area of the Black Sea followed, forcing many people to abandon villages and move closer as the sea level dropped.

But everywhere else, sea level was rising.

Around 14,000 years ago, glacial melting had caused sea levels, once much lower than today, to rise to within 100 meters of present levels. Pitman said sometime around 5600 B.C. the global sea level was high enough to flood the previously isolated Black Sea basin.

The water carved a gouge 500 meters deep as it poured in, leaving a flat layer of sediment that researchers were able to see in a sediment core. The layer differed from sediment beneath it because it did not show evidence of gradual deposition over time.

"This means the water came in in a huge rush," Pitman said. By his calculations, 12 cubic miles of water flowed through that groove over a 30 to 60 day time span.

"It had to be very fast?we call it a transgression," he said.

An area as big as Florida was flooded on the north side of the Black Sea, along with a Connecticut-sized ring around the perimeter.

"There were not many people around back then, and they tended to be around places they could do farming," Pitman said. Writing was developing around the same time, but Pitman said the stories were probably transferred away from the area orally and then written down later.