Nuclear explosion-level event gouged a 600ft-deep hole in China 20 million years ago

An impact crater that was made by an asteroid millions of years ago was discovered in a remote hillside of China this year. Scientists have since been studying the massive hole and have concluded that it was not an average asteroid strike, but was the result of a "nuclear explosion level" event.

The crater is oval and uneven from the sides. It is huge but escaped detection for all these years because it was filled with sediment. It measures up to 4,460 feet across and is 600 feet deep. 

Ming Chen, who was involved in the discovery, says the crater was believed to have been gouged sometime in the past 20 million years. Chen is a staff scientist at the Center for High Pressure Science and Technology Advanced Research in China. The findings were published on Nov 19 in the journal Matter and Radiation at Extremes.

The Hailin crater was found in a mountainous region known today as the Changbai Mountain Range and is the fourth impact crater discovered in China.

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It is the only one in the world located on a mountain ridge, according to the statement. Mountain ridge should not be confused with mountaintop, as the world's first known mountaintop impact crater is also in northeastern China.

Crater has an odd shape

The Hailin crater has a jagged terrain beneath which has resulted in its elliptical shape. Researchers say the meteor struck the top of a ridge with sloping sides, creating a relatively small diameter as measured perpendicular to the ridge. It is about 3,770 feet on one side with a longer diameter along the ridge line of 4,460 feet, according to the study.

It isn't fully complete, losing a part of its eastern rim due to certain geological purposes which the study doesn't explain. The study says there is also evidence of an ancient river at the site which drained when the eastern rim collapsed. The crater was filled with sediments and rocks, which upon analysis revealed an asteroid impact. Scientists noted deformations in the quartz grains that they say could only have been triggered by the shock of a huge impact.

"The discovery of the Hailin crater and other craters in China indicates that meteorite impacts at such scale could occur on Earth again in the future," Chen said in the statement.

More studies of the crater have been planned, as the researchers will soon dig into the hole to learn more about how the crater might have evolved.