Impact crater in south China confirmed as world's largest for over 10,000-year period
GUANGZHOU, Oct. 22 (Xinhua) -- The Jinlin impact crater in south China's Guangdong Province has been confirmed as the largest known crater on Earth since the Holocene period, which spans from 11,700 years ago to the present, the China Academy of Engineering Physics (CAEP) said on Wednesday.
The Jinlin impact crater is located in a low mountainous area of Deqing County in northwest Guangdong Province. Researchers estimated that the impact event occurred in the early-to-middle Holocene based on an analysis of the chemical weathering rate of local granite, and that the crater is a relatively young impact structure.
Their findings were recently published in the Matter and Radiation at Extremes journal. Chen Ming, the first author of the paper and a researcher at CAEP's Center for High Pressure Science and Technology Advanced Research, said that through field investigation and geological sample testing, they found evidence of shock metamorphism in rocks and minerals caused by strong shock waves in the crater.
They used this evidence to determine that the crater resulted from the hypervelocity impact of a small extraterrestrial body, rather than from Earth's own geological processes.
Chen said that previously discovered Holocene impact craters around the world are generally small in scale -- most measuring less than 100 meters in diameter, with the largest being about 300 meters. The Jinlin crater has a diameter of 900 meters, leading researchers to estimate that the impact had been huge, with an energy equivalent to 600,000 tonnes of TNT.
In the past, only four impact craters have been found in China's northeastern regions. In south China, no traces had been found for a long time due to destruction caused by the intense chemical and biological weathering of the region's surface rock layers.
These findings provide valuable insights for the study of impact craters worldwide, especially in warm and humid tropical and subtropical areas. They also expand the spatial distribution data of small body impact events globally. ■
