A great flood at the dawn of Chinese civilization, around 2,000 BC, was said to have swept away settlements, the water rising so high that it overran hills, mountains and even heaven itself. The legend tells that the divine King Yu, with the help of a tortoise and a dragon, tamed the waters by building ditches and dams, thus earning a mandate to rule and laying the foundation for China’s first dynasty, the Xia.
Now, a team of scientists led by Chinese seismologist Wu Qianlong, says there's evidence that a flood did indeed submerge a vast swathe of the country almost 4,000 years ago. In the Jishi Gorge, in what is now Qinghai province, they found remnants of a landslide caused by an earthquake, big enough to block the Yellow River. The pent-up river formed a big lake over several months that eventually breached the dam, believed to have been slightly smaller than the Hoover Dam, unleashing a cataclysm powerful enough to flood land 2,000 km downstream. "It's among the largest known floods to have happened on earth during the past 10,000 years," says geologist Darryl Granger.
In 2008, Wu traveled 25 kilometers downstream from the gorge, where the earthquake had destroyed numerous cave dwellings in a Neolithic settlement called Lajia. Subsequently, a thick layer of mud engulfed the ruins and the victims, which until now had preserved them for discovery. Wu found that the Lajia mud matched material from the Jishi Gorge, suggesting that the same earthquake that had destroyed the dwellings had also triggered the upstream landslide that set the stage for the flood. Deep cracks in the ground opened by the quake were filled by mud typical of a flood, indicating that the earthquake and flood must have occurred in the same year.
The researchers put the Yellow river flood at about 1920 BC by carbon dating the skeletons of children in a group of 14 victims found in Lajia. "Because children grow so quickly, their bones give a very accurate and reliable age at the time of their death. The three skeletons we dated and two others all agree perfectly well, and they tell us that the flood happened at 1922 BC, plus or minus about 28 years," Dr. Granger said. "So this coincides remarkably well with the major cultural transition in China."
The dates for the flood places the start of the Xia dynasty later than previously thought, in 1900 BC, rather than 2000 BC or earlier, as some timelines suggest. This means the dynasty existed squarely in the early Bronze Age, rather than the late Stone Age as previously though. The timing of the flood also marks the transition from the neolithic period to the early Bronze Age in China — a cultural shift with huge implications. About this time, urban areas and walled settlements appeared, including Erlitou, an archaeological site that has been linked to the Xia Dynasty (but has never been confirmed through archaeological evidence).
This is the first scientific evidence of not only China's Great Flood, but the existence of King Yu and the Xia dynasty itself, lending weight to the longstanding though controversial theory that the Xia Dynasty existed as China’s first unified state. Xia's existence has been contentious among archaeologists, because the only records of the Xia and the deluge were written about 1,000 years after the events were supposed to have happened. A compelling detail, however, is that the historical texts put Yu's efforts to stem the floodwaters in an area called 'Jishi.'
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Without written records tied directly to the civilization, some have said that the facts of the Xia have been inflated or outright fictionalized to shore up subsequent dynastic leaders and the 'mandate of heaven' that allowed them to rule. But if the legend is true, it means that this flood gave rise to one of the world's oldest and most enduring civilizations, enhancing our understanding of how catastrophes have shaped and guided human progress.