Hummeln
Key facts
- Country
- Sweden
- Diameter
- 1.2 km
- Age
- about 465 million years
- Location
- 57.37° N, 16.25° E
Lake Hummeln, a small round lake about 1.2 km across in the forests of Småland, southern Sweden.
Hummeln is a small impact crater about 1.2 km across, filled by the round waters of Lake Hummeln in the province of Småland, south-eastern Sweden.
What it hit. About 465 million years ago, in the Ordovician, a small asteroid fell into a shallow sea and struck the crystalline basement of the Baltic Shield, mostly granite. The crater was later filled with sediments, including limestone, which have since been partly eroded.
Proof of impact. Geologists long suspected that the round lake was a crater. Study of rocks and sediment from the crater found breccia and quartz grains with planar deformation features, produced only by shock, confirming an impact.
Age. Fossils in the sediments that filled the crater show that it formed in the Ordovician, during a period when the Earth was receiving many more meteorites than it does today.
Why it matters. Hummeln is one of several small Swedish craters that formed during the Ordovician meteorite shower, after an asteroid broke up in the asteroid belt about 466 million years ago. Together they show that the shower produced craters as well as the fossil meteorites found in Swedish limestone. The impactor is unknown.
Visiting. The lake is surrounded by forest, with a small road nearby.
Did you know?
Lake Hummeln fills a crater about 465 million years old.
It is one of several Swedish craters linked to the Ordovician meteorite shower.
The crater formed in a shallow sea.