Dronino iron meteorite
Oleg N. Guskov
In early April this year, Moscow resident Oleg Nikolayevich Gus'kov brought a piece of iron to the laboratory. According to Gus'kov, he was returning home from collecting mushrooms near the village of Dronino, Kasimovsky Raion, Ryazan Oblast. As he walked along a path leading along the edge of a forest, he noticed a rusty piece of metal sticking out of the white clay soil. Oleg Nikolayevich tried unsuccessfully to dig it out with his knife. He decided that perhaps the piece of metal was a meteorite, went home for a shovel and wheelbarrow, dug the piece up and brought it home. This happened during the hot month of July, 2000.
The piece of iron lay in his yard for two years and broke into three pieces. Oleg Nikolayevich sawed open one of the pieces and became more convinced than ever that he had found a meteorite. He began looking for experts who could help him learn more. He first met Mr. A. Milanovsky, a meteorite trader, whom Gus'kov had read an article about in Komosomolskaya Pravda. Milanovsky became enthusiastic about the find and even paid a visit to the village of Dronino to look for more fragments, but found nothing. Mr. Gus'kov felt that further efforts by Milanovsky were likely to be unsuccessful, so he searched further and found our Meteorites Laboratory.
The Laboratory's analysis showed that the Dronino Iron has a meteorite origin. Further, the shape of the sample suggested that this meteorite might have exploded as it passed through Earth's atmosphere, and that it might be possible to find more pieces.
As soon as the snow melted, the Laboratory sent an expedition to Dronino. Mr. Gus'kov participated in the expedition and proved a most welcoming host. The site where the meteorite had been found was carefully studied, but on the expedition's first day we found only one new fragment.
Finding the new fragment was extremely helpful as it allowed the meteorite's ground track to be estimated. Over the next few days we found more than 250 fragments weighing more than 550 kg - a whole meteorite shower.
Based on the distribution of the meteorite fragments and the depth they were found at, we estimate that when it hit the meteorite blasted out a funnel-shaped crater about 30 m in diameter, although this crater is not reflected in the present-day topography of the site.
After preliminary investigations the meteorite will be presented to the Meteoritical Society, the world registration body for meteorites, and will receive the name Dronino according to the rules of naming meteorites. Dronino is the 111th meteorite and only the third iron-meteorite shower found in Russia in the last 250 years.
The Dronino fragments are heavily rusted, indicating they fell long ago.
The village of Dronino is located 20 km from the town of Kasimov. Kasimov was founded in 1152 by Prince Yuri Dolgoruky and was orginally named Meschersky Gorodok. The famous prince of Novgorod, Alexander Nevsky, died in Meschersky Gorodok.
The original mass of the Dronino meteorite is estimated as at least 1.5 tons. Its fall would have caused an explosion equivalent to approximately 100 tons of TNT. If a meteorite as large as this had fallen during historic times, it would likely have been by the local population in Kasimov and farther away in Ryazan, Murom and Vladimir, and would have appeared in the local chronicles. But no written reports of such an event have yet been found. So it appears likely that the Dronino meteorite fell earlier than the 12th century in an area that was at that time largely unpopulated.
Scientists think that large bodies of iron form by differentiation of asteroids. The heavy metal sinks to the middle and builds up there. This process is used to explain the origin of Earth's iron core. According to first impressions the characteristics of the Dronino meteorite appear unique and hold out much promise to help understand the dynamics of this iron-migration process and the formation of metallic objects in the Solar System.