Kaali crater

The crater as viewed from near the rim

The main crater is nearly circular. When the water level is low, rocks can be seen penetrating the surface in the middle of the crater.

Tilted dolomite bedrock in the walls of the main crater

Kaali is a group of nine meteorite craters in the village of Kaali on the Estonian island of Saaremaa.<ref name=raukas>Template:Cite Earth Impact DB</ref> Most recent estimates put its formation shortly after 1530–1450 BC (3237 ± 10 ¹⁴C yr BP).<ref>Template:Cite journal</ref> 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 in Australia and Carancas crater in Peru).

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<ref>Template:Cite web</ref> in 1928, 1933 and 1937.

Formation

The impact is thought to have happened in the Holocene period, around 3,500 years ago.<ref name="Bianca">Bianca Mikovitš. Teadlaste töö tulemus Kaali kraatri vanuse määramisel ühtib vana regilauluga Maaleht, January 26, 2016</ref> The estimates of the age of the Kaali impact structure (Saaremaa Island, Estonia) provided by different authors vary by as much as 6,000 years, ranging from ~6,400 to ~400 years 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.<ref>Template:Cite journal</ref> A study based on elevated iridium signal in a nearby bog suggested the much younger age of 4th century BC.<ref>Template:Cite journal</ref> The craters were formed by a meteor with an estimated impact velocity of between Template:Cvt with a total mass of between 20 and 80 metric tonnes. According to some researchers the meteor arrived from the north-east.<ref name=wonder>Template:Cite web</ref>

At an altitude of Template:Cvt, the meteor broke into pieces and fell to the Earth in fragments, the largest of which produced a crater with a diameter of Template:Cvt and a depth of Template:Cvt. The explosion removed approximately Template:Cvt of dolomite and other rocks and formed a Template:Cvt tall, extremely hot gas flow. Vegetation was incinerated up to Template:Cvt from the impact site.<ref name=wonder />

Lake Kaali (Template:Langx) is on the bottom of this crater. Eight smaller craters are also associated with this bombardment of meteor fragments. Their diameters range from Template:Cvt and their respective depths vary from Template:Convert. They are all within Template:Convert of the main crater.

Effects

According to the theory of more recent impact, Estonia at the time of impact was in the Nordic Bronze Age and the site was forested with a small human population. The impact energy of about 80 TJ (20 kilotons of TNT) is comparable with that of the Hiroshima bomb blast. It incinerated forests within a Template:Cvt radius.<ref name="MPS">Template:Cite journal</ref>

In mythology

Scholars, such as Karl Kello,<ref>Template:Cite book</ref> maintain that the event featured prominently in regional mythology. It was, and still is, considered a sacred lake. There is archaeological evidenceTemplate:Clarify that it may well have been a place of ritual sacrifice. At some point during the early Iron Age, the lake was surrounded by a stone wall Template:Cvt long, with a median width of about Template:Cvt and an average height of Template:Cvt.Template:Citation needed

Finnish mythology has stories that may originate with the formation of Kaali. One of them is in runes 47, 48 and 49 of the Kalevala epic: Louhi, the evil wizard, steals the Sun and fire from people, causing total darkness. Ukko, the god of the sky, orders a new Sun to be made from a spark. The virgin of the air starts to make a new Sun, but the spark drops from the sky and hits the ground. This spark goes to an "Aluen" or "Kalevan"<ref name="Silverwhite">Template:Cite book</ref> lake and causes its water to rise. Finnish heroes see the ball of fire falling somewhere "behind the Neva River" (the direction of Estonia from Karelia). The heroes head in that direction to seek fire, and they finally gather flames from a forest fire.

According to a theory proposed by Lennart Meri, it is possible that Saaremaa was the legendary Thule island, first mentioned by ancient Greek geographer Pytheas, and the name Thule could have been connected to the Finnic word tule '(of) fire'<ref>Template:Cite book</ref> and the folklore of Estonia, which depicts the birth of the crater lake in Kaali. Kaali was considered the place where "The sun went to rest."<ref name="Silverwhite" />

The main crater

Namesake

The asteroid 4227 Kaali is named after it. Except for their names, there is no connection between this asteroid and the crater.

Meteoritic iron artefacts

In 2023, archaeologists analysed the Bronze Age Mörigen Arrowhead, found in Switzerland; it was made of meteoritic iron whose composition suggested its origin from the Kaali meteorite.<ref>Template:Cite journal</ref>

References

• Template:Cite journal
• Template:Cite book

External links

• About Kaali crater on the official Saaremaa website
• Photos of the Kaali crater
• Impact tectonics
• Interactive panoramic aerial view of the Kaali crater area