The China Academy of Engineering Physics (CAEP) verified on Wednesday that the Jinlin impact crater in south China's Guangdong Province is the largest known crater on Earth since the Holocene epoch, which lasts 11,700 years.
The Jinlin impact crater is located in the low mountainous terrain of Deqing County, northwest Guangdong Province. Based on an investigation of the chemical weathering rate of surrounding granite, researchers concluded that the impact event happened in the early to middle Holocene, and that the crater is a relatively young impact formation.
Their findings were just published in the journal Matter and Radiation at Extremes. Chen Ming, the paper's first author and a researcher at CAEP's Center for High Pressure Science and Technology Advanced Research, stated that field investigations and geological sample testing revealed evidence of shock metamorphism in rocks and minerals caused by strong shock waves in the crater.
They utilized this information to conclude that the crater was caused by the hypervelocity impact of a small extraterrestrial body, rather than by Earth's natural geological processes.
Chen stated that previously discovered Holocene impact craters around the planet are generally tiny in scale, with the majority measuring less than 100 meters in diameter and the largest measuring approximately 300 meters. The Jinlin crater has a diameter of 900 meters, prompting geologists to estimate that the impact was massive, with energy equivalent to 600,000 tonnes of TNT.
Previously, just four impact craters were discovered in China's northern provinces. There had been no traces in south China for a long time due to degradation caused by significant chemical and biological weathering of the region's surface rock strata.
These findings are important for understanding impact craters around the planet, particularly in warm and humid tropical and subtropical regions. They also broaden the spatial distribution data for small body impact incidents worldwide.
