Aug 4, 2016
Evidence for China's Great Flood Found
Folk traditions and written records recount how the hero Yu dredged and tamed the destructive floodwaters about 4,000 years ago.
Yu's decades-long feat earned him "the divine mandate to establish the Xia dynasty, the first in Chinese history, and marked the beginning of Chinese civilization," Qinglong Wu, a researcher at Peking University and Nanjing Normal University, China, and colleagues wrote in Science.
Until now no direct evidence of the cataclysm had been discovered.
"In the absence of geological evidence for such a flood, some scholars have argued that the story is either a historicized version of an older myth or propaganda to justify the centralized power of imperial rule," David Montgomery, professor of Earth and Space Sciences at the University of Washington in Seattle, wrote in a related Science paper.
Mapping distinctive sediments that are widely distributed along the Yellow River valley, Wu and colleagues were able to reconstruct the sequence of events that led to the flood. The sediments included deposits sourced from the gorge upstream.
"They are the direct and solid evidence of a great flood. Only a large flood can deposits such sediments," Wu told Discovery News.
According to the researchers, it all began with an earthquake which destroyed the Lajia site, a settlement of the Qijia culture, which is famous for having produced the world's earliest noodles.
Cave dwellings at Lajia collapsed, killing all the people there.
But the quake was even more destructive. It triggered a massive rock slide that dammed the river and backed up a lake.
"The lake was at least 200 meters (approx. 650 feet) deep," Purdue University professor Darryl Granger said.
Within six to nine months, the lake overflowed and the landslide dam failed catastrophically, sweeping over the Lajia site.
The researchers were able to determine the dimension of the flood channel and exactly how high the flood waters reached.
"The evidence found in our investigations along the Yellow River in Qinghai Province includes remains of a landslide dam, dammed lake sediments upstream, and outburst flood sediments downstream that allow us to reconstruct the size of the lake and flood," the researchers wrote.
The ancient landslide dam deposits reach an elevation of 785 feet above the present river level and stretch for more than 4,200 feet along Jishi Gorge.
Overall, the flood that broke the dam was of enormous proportions.
"It was about 300-500,000 cubic meters per second. To put that into perspective, it is among the largest known floods to have happened on Earth during the past 10,000 years," Granger said.
Using radiocarbon dating techniques on samples that included the skeletons of children who died in the earthquake at Lajia, the researchers dated the flood to 1920 B.C.
Read more at Discovery News