Rare Geological Phenomenon: Cluster of 49 Sinkholes Discovered in China

A giant karst sinkhole () cluster has just been discovered in northwest China, and geologists think that this could be the biggest yet.

China Daily said that the news was confirmed by the Shaanxi provincial government on Thursday. The report added that it took the experts four months to inspect the 5,000-square-kilometer area of the sinkhole group, which was located between 32 and 33 degrees north latitude.

The team of experts includes those from UNESCO International Research Center on Karst, International Union of Speleology and other research bodies of Czech, France and China.

Reports said there were a total of 49 sinkholes found in the core area: one superbig sinkhole, 17 large sinkholes and 31 average-sized sinkholes. The sinkhole cluster covers over four counties in Hanzhong City: Ningqiang, Nanzheng, Xixiang and Zhenba.

"The largest one was in Zhenba, which had the largest diameter of 520 meters and a maximum depth of 320 meters," Wang Weihua, Chief of Department of Land and Resources of Shaanxi, told China Daily.

Local news agency Xinhua reported that Liu Tongliang, head of the karst geology research institute under the Chinese Academy of Geological Sciences (CAGS) said a total of nine tiankengs and over 50 funnels of between 50 to 100 meters in diameter were found in the over 200-kilometer karst landform belt in Hanzhong City.

Quoting Wang, Xinhua wrote, "The expert panel agreed, the Hanzhong tiankeng cluster is rare, complete and spectacular in landscape. It has met international geological standards and has potential scientific and tourism value."

Science Alert said karst landforms are the result of soluble rocks such as limestone, dolomite and gypsum dissipating, giving rise to subterranean drainage systems with sinkholes, caves, and tunnels.

Sinkholes are rare and amazing geological phenomenon which would fill gaps in the research of karst geology. Before this recent discovery, there were only 130 tiankengs in the world, with over 90 in China.