Wanapitei
Key facts
- Country
- Canada
- Diameter
- 7.5 km
- Age
- 37.2 ± 1.2 million years
- Location
- 46.75° N, 80.75° W
Lake Wanapitei, a large lake just north-east of Sudbury, Ontario. The crater lies under the lake's southern part; boulders of impact rock lie along its shores.
Wanapitei is an impact crater about 7.5 km across that lies under the waters of Lake Wanapitei, just north-east of the city of Sudbury in Ontario, Canada. It is a much younger and smaller neighbour of the giant Sudbury structure, and it formed about 37 million years ago, in the late Eocene.
A crater found from boulders. Nobody can see the crater itself. Its existence was revealed by loose blocks of unusual rock scattered on the southern shore and in glacial deposits south of the lake. During the last ice age, ice sheets scraped rock from the lake bed and carried it southwards. Some of these blocks are impact breccia and impact melt rock, and their quartz grains show planar deformation features and other signs of shock. In the 1970s geologists traced the boulders back to the lake and confirmed a buried crater with gravity measurements.
What it hit. The impactor struck ancient metamorphosed sedimentary rocks, more than 2 billion years old, near the edge of the much older Sudbury structure. Dating the melted rock in the boulders gave the age.
Two impacts, one place. It is a coincidence that two impacts, nearly two billion years apart, struck almost the same spot. Wanapitei is far younger and far smaller than Sudbury, and the two are unrelated.
Why it matters. Wanapitei shows that a crater can be found even when it is completely hidden, by tracing the debris that ice has carried away. The impactor is unknown.
Did you know?
The crater was found from boulders of impact rock carried south by glaciers.
It lies right next to the Sudbury structure, which is nearly two billion years older.
The crater is completely hidden under the waters of Lake Wanapitei.