Giant sinkhole with a forest inside found in China

Live Science ^ | Stephanie Pappas

[BenLurkin]

The sinkhole is 630 feet (192 meters) deep, according to the Xinhua news agency, deep enough to just swallow St. Louis' Gateway Arch. A team of speleologists and spelunkers rappelled into the sinkhole on Friday (May 6), discovering that there are three cave entrances in the chasm, as well as ancient trees 131 feet (40 m) tall, stretching their branches toward the sunlight that filters through the sinkhole entrance.

The discovery is no surprise, Veni told Live Science, because southern China is home to karst topography, a landscape prone to dramatic sinkholes and otherworldly caves. Karst landscapes are formed primarily by the dissolution of bedrock, Veni said. Rainwater, which is slightly acidic, picks up carbon dioxide as it runs through the soil, becoming more acidic. It then trickles, rushes and flows through cracks in the bedrock, slowly widening them into tunnels and voids. Over time, if a cave chamber gets large enough, the ceiling can gradually collapse, opening up huge sinkholes.

In fact, 25% of the United States is karst or pseudokarst, which features caves carved by factors other than dissolution, such as volcanics or wind, Veni said. About 20% of the world's landmass is made of one of these two cave-rich landscapes.

The sinkhole's interior is 1,004 feet (306 m) long and 492 feet (150 m) wide, Zhang Yuanhai, a senior engineer with the Institute of Karst Geology, told Xinhua. The Mandarin word for such enormous sinkholes is "tiankeng," or "heavenly pit," and the bottom of the sinkhole did indeed seem like another world. Chen Lixin, who led the cave expedition team, told Xinhua that the dense undergrowth on the sinkhole floor was as high as a person's shoulders. Karst caves and sinkholes can provide an oasis for life, Veni said.

[Theophilus]

Sun comes up at 1145. Sun goes down at 1215.

[BipolarBob]

“Now are we gonna have dinosaurs on our dinosaur tour?”

[SunkenCiv]

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