Kaali impact craterWhen we think of the results of meteorites slamming into our planet’s surfa
Kaali impact craterWhen we think of the results of meteorites slamming into our planet’s surface we usually think big, from the relatively small 1.2km Barringer meteor crater in Arizona to the whopping 300km Vreedefort impact in South Africa. However, there are plenty of tiddlers dotting the world, including a group of 9 craters on Saaremaa island in Estonia that formed sometime between 7,600 and 4,000 years ago (based on studies of the crater lake sediments compared with estimated sedimentation rates and trying to date the layer containing the impact spherules of molten and frozen silica).Their mode of formation was only confirmed in the 1920’s, and is the only confirmed impact to have taken place in a more densely populated part of the world. The meteorite broke up 5-10 km up in the atmosphere, raining fragments on the land below, of which the largest formed the 110 metre diameter crater in the photo. The impacted rocks were Silurian dolomites (a magnesium rich limestone), and research shows vegetation was carbonised within a 6km radius of impact. The other craters in the series range from 12 to 40 metres across and are all within 1km of the main hit, showing that the pieces spread little after the atmospheric break up.The lake has been considered sacred for millennia, and may have been a place of ritual sacrifice. The great epic of Finnish myths called the Kalevela, parts of which date back very far into the past, may record the event in some of its tales that recount balls of fire falling from the sky and mythologise them as a new sun, created to replace the original one stolen by a wizard. The heroes go in its direction seeking fire, and encounter a giant forest fire. Estonian myth records it as the place the sun went to rest. The ex president of Estonia wrote a book on the crater suggesting that it may be the origin of the midsummer bonfires tradition, done in reenactment of the original event.LozImage credit: Wikimedia Commonshttp://www.baltictimes.com/news/articles/13029/#.Ux5BtoWdGnYhttp://www.wondermondo.com/Countries/E/Estonia/Saaremaa/Kaali.htmAn article on its cultural and archaeological impact:http://www.gi.ee/~veski/Veski%20Kaali%20review.pdf -- source link
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