Lasnamäe meteorite-print in Tallinn
Estonia has been covered with ice for several times, it smoothed and polished the ground and now we can see scrapes and grooves on the top layer of the ground. In most part, these are under the soil, but in Northern Estonia, where the soil layer is thin, or, in some cases, absent, finding these scrapes, left by ice, is not unusual.
Many can be seen in Tallinn, in Lasnamäe district. At present, it is possible to find these furrows in the intersection of Laagna and J. Smuuli road, on the right hand side, driving from the Narva road.
In 1983, during the excavation of Lasnamäe road, geologists found an interesting thing. On the limestone ground, freed of 5 m of lake lime sediment and peat, a network of grooves was discovered. Expanding from one center point to different directions and being connected at different places with smaller arching grooves, this imprint resembled a giant spiderweb.
This network of scrapes is similar to the typical disintegration form of a slab-shaped object on strong point-impact. This imprint was found underneath layer of peat, that was 5 m thick and had laid undisturbed for about 10,000 years. It also bore clear marks of grooves left by ice, thus, the print cannot be associated with human activity (not even with an explosion on a battlefield).
It is true, that bombs and shells can leave similar marks on limestone, but 25,000 years and even 5000 years ago (according to the sediments), neither existed.
We are left with supposition, that a meteorite fell on the limestone, which created the visible print and crater-like formation. Ice carried away the crater, which was made of small rocks, and left behind the imprint on the ground.
After finding this, the researchers turned to the city government, proposing to build a protecting and conserving facility, with overlooking balcony, on top of the imprint. Unfortunately, time was no right for this sort of plan, and is not even today.
Perhaps, it is better that now, the unique print lays under several layers of artificial soil, in a location only known to scientists, and waits for better days - reasonable conservation and opening to visitors.
In 2008, "Tähesaju City" (Star fall City) was opened in the area of the imprint; the choice of name, of course, was not random.
Sources: brochure "Loodusmälestised 4, Tallinn - Lasnamäe, Pirita" Teaduste Akadeemia Kirjastus, Tallinn 1999