Discovery of a primitive forest at the bottom of a ‘giant sinkhole’ in China

Context

An ancient forest has been discovered with trees at the bottom of a Giant karst sinkhole in Leye County in South China’s Guangxi Zhuang Autonomous Region.

About

• 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 intcaverns.
• 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.
  

How are sinkholes formed?

• Sinkholes are depressions formed in the ground when layers of the Earth’s surface start collapsing intcaverns. 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 tobig.
• Sinkholes can be formed due tnatural 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 alsbe formed due thuman activity due tbroken land drains, water mains and sewerage pipes, increased rainfall, storm events, underlying limestone and diverted surface water, among other reasons.

Sinkholes in China and around the world

• In China, the mining of coal, zinc, lead and iron ore deposits in karst areas have been associated with the formation of sinkholes due thuman activity, according ta 1997 paper published in the journal Environmental Geology.
• Sinkholes are not uncommon in other parts of the world.
• Other sinkhole-prone areas around the world include Mexico, parts of Italy and Russia.