Kaali crater
Kaali is a group of 9 meteorite craters in the village of Kaali on the Estonian island of Saaremaa. Most recent estimates put its formation shortly after 1530–1450 BCE (3237+/-10 14C yr BP). It was created by an impact event and is one of the few impact events that has occurred in a populated area (other ones are: Henbury craters and Carancas crater). Before the 1930s there were several hypotheses about the origin of the crater, including theories involving vulcanism and karst processes. Its meteoritic origins were first conclusively demonstrated by Ivan Reinvald in 1928, 1933 and 1937.
The impact is thought to have happened in the Holocene period, around 3,500 years ago. The estimates of the age of the Kaali impact structure (Saaremaa Island, Estonia) provided by different authors vary by as much as 6000 years, ranging from ~6400 to ~400 before current era (BCE). Analysis of silicate spherules in Estonian bogs show that the possible age of the impact craters could be approximately 7,600 years. A study based on elevated Ir signal in a nearby bog suggested much younger age of 4th century BC. The craters were formed by a meteor with an estimated impact velocity of between 10 and 20 km/s with a total mass of between 20 and 80 metric tonnes. According to some researchers the meteor arrived from the north-east.
At an altitude of 5–10 km, the meteor broke into pieces and fell to the Earth in fragments, the greatest of which produced a crater with a diameter of 110 m and a depth of 22 m. The explosion removed approximately 81,000 cubic meters of dolomite and other rocks and formed a 7–8 km tall, extremely hot gas flow. Vegetation was incinerated up to 6 km from the impact site.
Kaali Lake (Estonian: Kaali järv) is on the bottom of this crater. Eight smaller craters are also associated with this bombardment. Their diameters range from 12 to 40 meters and their respective depths vary from one to four meters. They are all within one kilometer of the main crater.
...
Wikipedia