Iso-Naakkima is a lake in Southern Savonia, Finland, about 10 km south of the town of Pieksämäki. It is notable for having an eroded impact crater under the northwestern part of the lake. It is one of the oldest known, about 1200 million years old (900–1200 Ma, Mesoproterozoic). Of the known craters older than a billion years old, it is also one of the smallest being only 3 km in diameter.
See also
- Impact craters in Finland
References
External links
- Iso-Naakkima impact structure
- Iso Naakkima impact structure — Division of Geophysics, University of Helsinki