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

Context

A cave exploration team has discovered an ancient forest at the bottom of a giant karst sinkhole in Leye County in south China’s Guangxi Zhuang Autonomous Region.

About

The sinkhole measures 306 metres in length, is 150 metres in width and 192 metres in depth, with its volume exceeding 5 million cubic meters.
Given these dimensions, the sinkhole can be categorised as a large sinkhole.
In Mandarin, giant sinkholes are called Tiankeng or “heavenly pit”.

About Sinkhole:

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.
Essentially, this means that when rainwater seeps into the ground, the rock below the surface of the Earth starts dissolving, leading to the creation of spaces.
This process is a slow and gradual one and can sometimes take hundreds or thousands of years.
As per NASA, karst geology covers about 13 per cent of eastern and south-eastern Asia.
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.

Karst Landscape:

Karst is an area of land made up of limestone.
Limestone, also known as chalk or calcium carbonate, is a soft rock that dissolves in water.
As rainwater seeps into the rock, it slowly erodes.
Karst landscapes can be worn away from the top or dissolved from a weak point inside the rock.
Karst landscapes feature caves, underground streams and sinkholes on the surface.
Where erosion has worn away the land above ground, steep rocky cliffs are visible.
Shilinis a karst formation in southern China. In Chinese, shilin means stone forest.
Shilin got its name because the tall rocks that formed due to erosion look like stone trees.
Shilin is part of a larger karst landscape called the South China Karst, which spreads across the Chinese provinces of Guangxi, Guizhou, and Yunnan.