New Karst Sinkhole:
A cave exploration team has discovered an ancient forest with trees nearly 40 metres high at the bottom of a giant karst sinkhole in Leye County in south China’s Guangxi Zhuang Autonomous Region.
- In Mandarin, giant sinkholes are called Tiankeng or “heavenly pit”.
- Sinkholes are depressions formed in the ground when layers of the Earth’s surface start collapsing into caverns.
- They can occur suddenly and without warning, because the land under the surface of the Earth can stay intact for a period of time until the spaces get too big.
- Sinkholes can be formed due to natural processes or human activity.
- Typically, sinkholes form in areas of “karst” terrains, where the rock below the surface of the Earth can be easily dissolved by groundwater.
- Karst terrain is created from the dissolution of soluble rocks, mostly limestone and dolomite and is characterised by distinctive landforms such as caves, sinkholes and springs.
- Sinkholes can also be formed due to human activity due to broken land drains, water mains and sewerage pipes, increased rainfall, storm events, underlying limestone and diverted surface water, among other reasons.