Baijifeng impact crater discovered - Dr. Ming Chen

Recently, a research team led by Chen Ming from Center for High Pressure Science & Technology Advanced Research made a breakthrough in the study of terrestrial impact structures —— the finding of Baijifeng impact structure in Tonghua city, Jilin province —— the third impact crater found in China, and the world's first impact crater formed on the top of a high mountain. Related study entitled "Discovery of the Baijifeng impact structure in Tonghua, Jilin, China" is published in the latest issue of the journal Matter and Radiation at Extremes.

Terrestrial impact structures were formed by hypervelocity impacts of asteroids or other celestial objiects into the Earth's surface. The impact structures on the Earth usually occur as bowl-shaped craters or circular depressions with central rings or central peaks. This newly discovered impact crater by Chen Ming's research team is located on the top of a high mountain in Baijifeng National Forest Park, more than 20 kilometers southeast of Tonghua City. It is a cirque-shaped depression, with a height difference of about 400 meters from the highest rim to the lowest rim. 

Baijifeng National Forest Park is a famous tourist attraction in Jilin Province, known for a the large number of "celestial stones" (formerly known as "basalt" stones) covered on the top of Baijifeng mountain. However, the formation and origin of these " celestial stones" has been an long-standing mystery in the past.

The study revealed that, in prehistoric times, an asteroid with tens of meters in diameter hit the top of the Baijifeng mountain at a cosmic speed, triggering a huge explosion and forming this crater. A huge amount of rocks was ejected from the crater. The original topography of the top of the mountain was reformed into two new peaks of "front Baijifeng" and "rear Baijifeng" with elevations of 1,318 meters and 1,300 meters, respectively.

Baijifeng Mountain is mainly composed of proterozoic sedimentary rock and Jurassic granite, The abundant rock fragments on the top and slopes of the mountain is the just the accumulation of the rocks ejected in the asteroid impact event, and thus finally unraveling the long-standing mystery of "celestial stone".

"Baijifeng impact crater is the third impact structure discovered in China so far. On the Earth, the occurrence that a large impact crater is located on the top of a high mountain is rarely seen. Baijifeng impact crater is the known impact structure with the largest vertical elevation difference on the Earth, and it is also the world's first-known mountaintop impact crater. " Dr.Chen Ming said. 

The discovery of Baijifeng impact crater not only enriches our understandings of the collision history of Earth, but also provides perspectives for exploring the cratering mechanism of special landforms and the shock metamorphic effects of material. “We will further explore the geological structure, the formation and evolution of the impact crater, the physical and chemical changes of the target material under the high temperature and high pressure caused by the shock wave, and the precise chronology of the impact event," added Dr. Ming Chen.

近日，北京高压科学研究中心陈鸣研究团队在星球撞击构造研究方面取得了新突破：在吉林省通化市发现一个形态和产状十分奇特的陨石坑：白鸡峰陨石坑¾我国第三个陨石坑，也是全球第一个高山顶上撞击的陨石坑。相关研究以 “Discovery of the Baijifeng impact structure in Tonghua, Jilin, China”为题发表在最新一期的《极端条件下的物质与辐射》（Matter and Radiation at Extremes）杂志上。