Fatal Flooding Destroyed China’s Liangzhu Culture 4,300 Years Ago

A thriving metropolis often referred to as “China’s Venice of the Stone Age” was mysteriously abandoned in approximately 2300 BC, leading to the extinction of China’s ancient Liangzhu culture. Now, a new analysis appearing in the journal Science Advances has finally revealed the truth about the catastrophic event that forced the people of the city of Liangzhu into permanent exile.

Unmistakable geological evidence has shown that the region of eastern China, where the city was located, experienced heavy flooding caused by an unusually intense monsoon sometime between 4,345 and 4,324 years ago. The flooding associated with this storm would have been so overwhelming that the residents of Liangzhu and the surrounding area would have had no choice but to flee, as rapidly as possible. While they could conceivably have returned to rebuild their city at some point, the archaeological record makes it clear that they never did.

Aerial view of the ruins of the UNESCO World Heritage Site of the city of the Liangzhu culture. (Hangzhou Liangzhu Archaeological - Site Administrative District Management Committee)

Aerial view of the ruins of the UNESCO World Heritage Site of the city of the Liangzhu culture. ( Hangzhou Liangzhu Archaeological – Site Administrative District Management Committee )

The Fabulous Life and Sudden Death of the Liangzhu Culture

One of the most advanced civilizations to appear during the late Neolithic Age was located in the Yangtze Delta, approximately 100 miles (160 km) southwest of Shanghai in China. It was centered in an urban settlement known as Liangzhu City, as years of productive archaeological excavations have revealed.

These explorations have unearthed ample evidence to establish the high level of material wealth achieved by the builders of the Neolithic Liangzhu culture . For example, the most advanced, large-scale water management system ever found in China was discovered at the Liangzhu City site.

The city built an impressive interlocking array of canals, reservoirs, and dams, which supplied the city’s residents with all the water they required while also supporting the irrigation of an abundant quantity of agricultural land outside the city’s walls. The canals were likely also used for travel, which explains the city’s identification with modern-day Venice.

The Liangzhu culture was at the height of its prosperity and power approximately 5,300 years ago. This was exhibited through their impressive and ingenuous infrastructure, and also through the elaborate carved jade objects they created in abundance. Archaeologists have recovered many burial goods of this type from the Liangzhu culture.

Jade cong artifact of the Liangzhu culture. (Zhejiang Provincial Institute of Cultural Relics and Archaeology)

Jade cong artifact of the Liangzhu culture. ( Zhejiang Provincial Institute of Cultural Relics and Archaeology )

But 1,000 years after reaching its peak, the Liangzhu culture suddenly vanished. According to the archaeological record, its people completely abandoned the great city they’d constructed and sustained over the course of many generations, never to return. In order to resolve the mystery once and for all, a team of international scientists led by Christoph Spötl, the head of the Quaternary Research Group in the University of Innsbruck’s Department of Geology, set out to find out of what caused the downfall of the Liangzhu culture.

Fortunately, the scientists didn’t have to start their investigation from scratch. Evidence had already emerged that suggested the city’s abandonment was related to flooding. “A thin layer of clay was found on the preserved ruins, which points to a possible connection between the demise of the advanced civilization and floods of the Yangtze River or floods from the East China Sea,” Spötl explained in a University of Innsbruck news release about his group’s study.

“No evidence could be found for human causes such as warlike conflicts. However, no clear conclusions on the cause were possible from the mud layer itself,” highlighted Spötl. To prove their suspicions about flooding were true, the researchers needed more evidence. They found it inside two caves very close to the Liangzhu City site.

Geological Record Reveals the Truth about Liangzhu Culture Climate Disaster

The geological record acts like an archive, in the way it records changes in the climate and the environment. Cave formation is one geological process that is strongly impacted by climate, and scientists who study ancient environmental conditions are often able to gain insights by analyzing what was happening inside caves.

For the latest study, Haiwei Zhang, a geologist from Xi’an Jiaotong University in Xi’an, China, was recruited to take samples from stalagmites inside two caves located just southwest of the Liangzhu City excavation site. “These caves have been well explored for years,” Spötl said. “They are located in the same area affected by the Southeast Asian monsoon as the Yangtze delta and their stalagmites provide a precise insight into the time of the collapse of the Liangzhu culture, which, according to archaeological findings, happened about 4,300 years ago.”

Stalagmites, along with other forms of cave dripstones, are calcium carbonate rock deposits left behind by water that drips or runs through the ceilings or down the walls of caves. The pace of calcium carbonate buildup is impacted by the amount of water running through a cave, which will obviously be altered by any flooding that occurs at the surface level.

Geologists and climate researchers have been looking for clues in stalagmites in order to understand the disappearance of the Liangzhu culture from the archaeological record. (Haiwei Zhang / Xi'an Jiaotong University)

Geologists and climate researchers have been looking for clues in stalagmites in order to understand the disappearance of the Liangzhu culture from the archaeological record. (Haiwei Zhang / Xi’an Jiaotong University )

If a cave has been flooded with unusual amounts of rainfall and run-off, it will cause changes in carbon isotope data. In this particular instance, the cave stalagmite samples collected by Haiwei Zhang were found to have been partially constructed during a period of extremely high rainfall, which occurred specifically between 4,345 and 4,324 years ago.

The time estimate was obtained through uranium-thorium dating procedures, which are accurate down to a range of plus or minus 30 years. According to Christoph Spötl, this is the smoking-gun evidence needed to link the fall of the Liangzhu culture with the onset of heavy and sustained flooding.

“The massive monsoon rains probably led to such severe flooding of the Yangtze and its branches that even the sophisticated dams and canals could no longer withstand these masses of water, destroying Liangzhu City and forcing people to flee,” explained Spötl. “The very humid climatic conditions continued intermittently for another 300 years, as the geologists show from the cave data.”

Presumably motivated by the long-term shift in the climate, the people of the Liangzhu culture decided to move inland and abandon their beloved home city for good. What would have been the point of rebuilding, they may have reasoned, if new outbreaks of massive flooding could happen at any time?

It isn’t known exactly what happened to the people of Liangzhu City after their great migration inland. The Liangzhu culture they built seems to have disappeared completely from the archaeological record from that point on, totally destroyed by an epic and unsurvivable climate disaster.

Top image: The analysis of dripstones within the Shennong Cave (main image) and Jiulong Cave provided scientists with evidence related to the collapse of the Liangzhu culture. Source: Haiwei Zhang / Xi’an Jiaotong University

By Nathan Falde

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