With a diameter of 900 meters, the Jinlin crater was discovered in southern China.
This is not just an ordinary crater but the largest impact crater in the world from the recent period. The crater was discovered by a team of Chinese researchers from several institutions in Shanghai and Guangzhou.
This crater is one of only about 200 craters identified worldwide and is very young geologically.
Based on nearby soil erosion, it was probably formed in the mid Holocene, the current geological period that began at the end of the last Ice Age, about 11,700 years ago.
Thanks to its enormous diameter, it is much larger impact than the Macha crater in Russia, which measures 300 meters.
Until this discovery, the Russian crater was considered the largest identified and dated to the Holocene.
“This discovery shows that the scale of impacts from small objects from outer space on Earth at that time is much bigger than previously recorded,” said Dr. Chen from the Guangzhou Geochemistry Institute.
In the case of the Chinese crater, the impact was caused by a small meteor, that left a crater with 10 km wide. However, research not determined whether the small meteor was made of iron or rock.
One of the features of this crater is how well it has been preserved, especially considering the monsoons in the region, heavy rains, and high humidity all conditions that accelerate soil erosion.
Within the layers that help preserve the structure of the crater, researchers found numerous quartz grains with unique micro features called planar deformation features. Geologists use these as evidence of different types of impacts from objects.
The formation of planar deformation features in quartz occurs only from intense shock waves generated by impacts from celestial bodies.
The formation pressure ranges from 10 to 35 gigapascals, a shock effect that cannot be produced by any geological process on Earth,” said Dr. Chen.
We believe that throughout Earth’s history.
However, geological differences mean that historical traces of these impacts erode at different rates, and some have disappeared completely.
This makes the discovery of the Jinlin crater particularly significant.
“The impact crater is a true record of Earth’s impact history,” said Dr. Chen. “Discovering the crater provides a more objective basis for understanding the distribution, geological evolution, impact history and regulation of small bodies landing from space.”