Suvasvesi North
Key facts
- Country
- Finland
- Diameter
- 3.5 km
- Age
- about 85 million years
- Location
- 62.70° N, 28.17° E
The round open water of Kuukkarinselkä, the northern basin of the lake Suvasvesi in eastern Finland, about 4 km across.
Suvasvesi North is an impact crater about 3.5 km across beneath Kuukkarinselkä, the northern part of the lake Suvasvesi in eastern Finland.
Discovery. The round shape of the basin and its depth suggested a crater. In 2001 geologists found shatter cones, cone-shaped fractures produced only by shock, confirming an impact. It became the sixth known impact crater in Finland. Drilling later recovered impact melt rock from beneath the lake bed.
What it hit. The impactor struck crystalline rocks of the Baltic Shield, gneiss and granite nearly 2 billion years old.
Age. Dating of the melt rock suggests an age of about 85 million years, in the Late Cretaceous, which would make it the youngest known crater in Finland.
A neighbour. A second structure, Suvasvesi South, lies only a few kilometres to the south. The two look like a pair, but dating shows they formed hundreds of millions of years apart.
Why it matters. Suvasvesi North shows how a round lake in a land of lakes can hide an impact crater. The impactor is unknown.
Did you know?
Suvasvesi North was confirmed by shatter cones found in 2001.
It may be the youngest known impact crater in Finland.
Its southern neighbour is hundreds of millions of years older.