A giant cluster of karst sinkholes in South China's Guangxi Zhuang autonomous region, Nov 2, 2019. [Photo/Xinhua]

"Some of the sinkholes are formed at a plateau 1,000 meters above sea level, and the others as a chain developed along underground rivers. The founding will be of significance for the theory of sinkholes evolution," said Jiang Zhongcheng, head of the institute.

Most of the sinkholes boast a volume of over 1 million cubic meters, and their original vegetation is largely intact and the trace of human activities is scant, according to the team.

The giant sinkholes, also known as Tiankeng in China, are dolines, or giant pits, with special geological features found in karst regions formed by repeated cave-ins. They are mainly found in China, Mexico and Papua New Guinea.

In 2001, geologist Zhu Xuewen proposed the Chinese name "Tiankeng" for dolines over 100 meters in depth, as there was no special term yet to define this unique geological feature.