In honor of International Asteroid Day, celebrated on June 30, NASA published a series of images of impact formations located in various corners of the Earth. Among them is the Yilan crater, recently discovered in China.
It may seem strange, but despite China’s large area (which significantly exceeds that of Australia), only one relatively small impact crater was known there until recently. The situation changed in 2021 when a group of geologists discovered a crater in Yilan County. It is located in the densely forested Lesser Xing’an mountain range. Interestingly, local residents have long been aware of the existence of this unusual structure and referred to it as a circular mountain range.
The image published by NASA was taken in October 2021 by the Landsat 8 satellite. The jagged northern rim of the Yilan crater stands out against the backdrop of autumn foliage.It rises 150 meters and is well preserved, while the southern third of the crater rim is missing.
The diameter of the crater is approximately 1.85 km, making it the largest crater on Earth less than 100,000 years old. Radiocarbon analysis of coal and organic lake sediments showed that it was formed between 46,000 and 53,000 years ago. For comparison, the famous Arizona crater is also about 50,000 years old, but its diameter is 1.2 km.
Although the asteroid that created the crater fell relatively recently (by geological standards), the granite rocks on which it fell were much older, having formed about 200 million years ago in the early Jurassic period. To investigate its structure, the research team drilled a 438-meter-deep borehole in the center of the crater, where they discovered hundreds of meters of ancient lake sediments and fragmented granite. Impact quartz, melted granite, glass with holes formed by gas bubbles, and teardrop-shaped glass fragments were found in the core. All this indicates a highly intense impact event.
Researchers continue to study the cause of the disappearance of the southern edge. However, the presence of lake sediments inside the crater indicates that the rim remained intact long enough for significant sediments to accumulate at the bottom of the lake. Such deposits often produce rich organic soil; several agricultural fields can be seen in the southern part of the crater. The rest of the crater’s interior is covered with swamps and forest wetlands.
In conclusion, it is worth noting that the formation of the Yilan crater could have been observed by ancient people who had already settled in the territory of modern China at that time. At that time, Neanderthals were still living in Europe.
Earlier, we reported on how NASA photographed the site of the Tunguska meteorite impact.
According to Earthobservatory
