Archeologists find proof of China’s Great Flood
4,000-year-old swelling of Yellow River could be linked to fabled first dynasty
Like others worldwide, ancient texts that describe the beginning of Chinese civilization mark it with a Great Flood.
China’s earliest written histories tell of a 22-year-long flood of the Yellow River and a hero, Yu the Great, who dredged the lands and returned order. Yu’s leadership earned him the divine mandate to establish Xia dynasty, China’s first.
The Xia Dynasty was succeeded by the Shang and every dynasty thereafter. But while the existence of the Shang is supported by archeological evidence, the Xia have remained a mystery. Was the Xia a real historical culture, or a convenient myth to support centuries of political succession?
Now, archeologists say they have stumbled across geological evidence of a devastating prehistoric flood of the Yellow River, providing tantalizing clues about the Xia.
“It’s among the largest known floods to have happened on Earth during the past 10,000 years,” said Darryl Granger, a geologist at Purdue University and co-author on a paper describing the findings, published Friday in the journal Science.
Other researchers were impressed by evidence of the natural disaster, but said archeologists will need to search for more proof of a related culture shift.
“I think the authors have made an extremely good case that there was some kind of major flood event,” said T.R. Kidder, an environmental archeologist from Washington University who works in China.
“What I am skeptical of, and what I think some of my colleagues are also skeptical of, is that they don’t demonstrate in any factual way a connection between that flood event and transformations well downstream.”
Qinglong Wu, an archeologist and first author on the paper, accidentally discovered hints of the flood when he found unusual sediments in the Yellow River’s Jishi Gorge in 2007. Subsequent research revealed a chilling picture.
Geological observations suggest that an ancient landslide created a dam that completely blocked the river, filling a lake that swelled until it rose as high as 210 metres above present river levels.
Six to nine months later, the water overtopped the dam and crumbled it, suddenly discharging up to 16 cubic kilometres of water and deluging the regions below. Downstream, the researchers found distinctive sediments associated with the outburst as high as 50 metres above present river levels.
The researchers’ calculations indicate that this would have ranked among the largest freshwater floods since the last ice age, about 11,700 years ago.
To pin down a date for the outburst, the researchers carbon-dated charcoal from the sediments. But the best evidence came from a pre-existing archeological site nearby: the lateNeolithic “Lajia” cave dwellings.
The Lajia dwellings are already famous for fuelling a long-standing culinary fight. In 2005, archaeologists reported the discovery of a sealed, well-preserved bowl of millet noodles, proving the Chinese were slurp- ing them 4,000 years ago, well before the first evidence of Italian or Arab noodles.
Noodles aside, Lajia is a sobering place, sometimes referred to as “Pompeii of the East.” Its occupants were crushed in mudslides triggered by an earthquake. The collapsed dwellings preserved numerous skeletons, including a woman with her arms wrapped protectively around a child.
When the researchers sampled the Lajia site, they discovered that sediments from the flood outburst had filled cracks caused by the earthquake before the next occurrence of the annual rains, meaning the flood had to have occurred the same year.
In fact, the researchers believe the earthquake that crushed Lajia probably also created the landslide dam at Jishi Gorge. More precise dating of the children’s skeletons provided a clearer estimated date for the flood: 1920 BC.
That date is significant. Thousands of kilometres downstream sits another archeological site known as Erlitou, a state-level civilization that arose in about 1900 BC and boasted rammed-earth walls, palatial dwellings and bronze technology.
For half a century, researchers have speculated that Erlitou could be the dynastic seat of the Xia. But because estimates put the beginning of the Xia to between 2200 and 2070 BC, the timing was off.
If the Jishi Gorge flood in 1920 BC preceded the rise of the Xia, the dates now line up. But was this catastrophic flood the same as the Great Flood of legend? Is it linked to the important cultural shifts happening in the plains way downstream?
The co-authors of the Science paper estimate that a flood of this size could have easily travelled more than 2,000 kilometres, breaching levees, backwashing into tributaries and causing widespread disruption.
Their research did not extend to the archeological sites way downstream like Erlitou. But Kidder notes there is no evidence of significant flooding in these areas where the Xia dynasty supposedly evolved.
Just because there isn’t evidence yet, though, “doesn’t mean it can’t be found,” Kidder said.
“They have provided the scholarly community with an intriguing hypothesis — they’ve given us things we can now go look for.”
“It’s among the largest known floods to have happened on Earth during the past 10,000 years” DARRYL GRANGER PURDUE UNIVERSITY