About 3,500 years ago, an ancient civilization emerged in eastern China and built a city like no other in Asia and possibly the rest of the world.
The remnants of the Liangzhou civilization, which flourished along the Yangtze River Delta in eastern China, are evidence of the unique achievements of this Neolithic community at the end of the Stone Age. The archeological ruins of Liangzhou City show numerous signs of social, cultural and technological progress, especially in the fields of agriculture and aquaculture. High-level architectural features, such as the clever engineering of hydraulic structures that enabled them to build canals, dams, and reservoirs, earned Liangzhou the nickname “Eastern Venice” during the Neolithic period.
Aerial view of Liangzhou Ancient Site
But none of these surprises lasted. After a millennium of creativity, the Liangzhou civilization mysteriously collapsed about 4,300 years ago and the ancient city was suddenly abandoned. The exact cause was never fully understood, but many cite the occurrence of a catastrophic flood as the main cause of this sudden decline.
“Geologist Christoph Sputel of the University of Innsbruck in Austria says:
A thin layer of clay has been found on the ruins, suggesting a possible link between the collapse of this advanced civilization and the Yangtze River floods or floods from the East China Sea.
But no clear result of the cause can be obtained by relying on the clay layer alone. We have just got a clearer picture of the flood that has engulfed this amazing place.
In a new study, Professor Spotel and an international team of researchers have gone much deeper than the ancient mud layer and studied cave structures, such as stalagmites, in two underwater caves in the area that retain chemical signs of past climatic conditions.
A study of stalagmite specimens led by Hai Zhang of China’s Zhi An Xiaotong University showed that the collapse of Liangzhou coincided with a period of heavy rainfall from 4345 to 4324 years ago. This was probably due to the increase in the frequency of the southern El Niوo-oscillation phenomenon.
According to Sputel:
These results are very accurate in terms of time. Heavy monsoon rains may have caused severe flooding of the Yangtze and its tributaries; Even advanced dams and canals could not withstand this volume of water, and Liangzhou City was destroyed and its inhabitants forced to flee.
The stalagmites of Shenong Cave revealed the secret of the fall of Liangzhou civilization
Older signs of climate change in the Yangtze River Delta may also have influenced other pre-Liangzhou prehistoric Neolithic civilizations that flourished during the dry, relatively rainy, and relatively stable climate, researchers said.
History and the weather show that this successful city could not last forever.
Researchers have written in their article:
Archaeological finds indicate the existence of complex aquatic structures such as the Great Earthen Dam near Liangzhou City (built between 5,300 and 4,700 years ago).
This shows that the Liangzhou community effectively managed water resources using water infrastructure for flood or irrigation to survive in a dry climate.
It seems that over time, this arid climate has gradually become drier, and about 4400 years ago it experienced a super-drought. At this point, dam construction stopped because the existing dams seemed sufficient in low rainfall conditions.
Then the rains began in two separate periods, approximately from 4400 to 4300 years ago.
The following is the article:
Our observations of stalagmite specimens along with geochemical evidence of flood deposits on the Liangzhou Civilization layer suggest that heavy rains across the middle and lower reaches of the Yangtze River Valley may have strengthened river and sea floods, impeding habitat and cultivation.
Large floods and flooding due to poor drainage in the lowlands may have forced the people of Liangzhou to leave the capital and their settlements in the Taihu Plain, which eventually led to the collapse of Liangzhou civilization.
For hundreds of years to come, the conditions remained humid. At this time other ancient civilizations temporarily grew to replace the Liangzhou civilization; At least until the next drought cloud that caused the final destruction of Neolithic communities in the area.
At the same time, Chinese society was beginning a new chapter in its history; Xia Dynasty was founded by the Great Yu in 2070 BC, which is the first dynasty of China.
Although many sources point out that Ruler Yu was able to establish the Xia Dynasty because of the successful management of the inundation, some studies suggest that Yu’s dominance over the inundations could be attributed to climate change.
Data from stalagmites also support this idea.
These observations provide strong evidence consistent with Chinese historical accounts and previous research into the emergence of the Xia Dynasty amid a large climate transition from wet to dry conditions.
The findings are published in the journal Science.