Yilan
Key facts
- Country
- China
- Diameter
- 1.85 km
- Age
- about 49,000 years
- Location
- 46.38° N, 129.31° E
A horseshoe-shaped ridge of wooded hills about 1.85 km across in Heilongjiang Province, north-eastern China, open to the south-east, with a swampy floor.
Yilan is an impact crater about 1.85 km across in Yilan County, Heilongjiang Province, north-eastern China. Its rim survives on only one side, forming a crescent of hills.
What can be seen. About two-thirds of the rim remain as a semicircle of wooded hills. The other side has been worn away by erosion or covered by sediment. The crater floor is a swampy, flat area of sediment.
What it hit. The impactor struck granite.
Proof of impact. In the late 2010s Chinese scientists studied the crater in detail, including drilling. Rocks from the rim and the crater fill contain quartz with planar deformation features, and the breccia contains glass formed by melting. These features confirmed an impact, and the results were published in 2020 and 2021.
Age. Radiocarbon dating of plant remains in lake sediments at the base of the crater fill shows that the crater formed about 49,000 years ago, give or take about 3,000 years.
Why it matters. Yilan is one of the youngest and best-preserved craters of its size in Asia, and its partly preserved rim shows how quickly erosion can remove part of a young crater. The impactor is unknown.
Did you know?
Only about two-thirds of Yilan's rim survive, forming a crescent of hills.
Radiocarbon dating shows it formed about 49,000 years ago.
It was confirmed as an impact crater in 2020.