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Seymchan (meteorite)
Encyclopedia
Seymchan is a pallasite
meteorite
found in 1967 in Russia
.
, Russia
, near the settlement of Seymchan
.
The main mass of 272.3 kg was found in June 1967 by the geologist F. A. Mednikov during a survey. The mass was a triangual shaped thumbprinted meteorite lying among the stones of the brook bed. A second specimen of 51 kg was found in October 1967 at a distance of 20 m from the first one by I. H. Markov with a mine detector 1967. The main mass was turned in to the Academy of Sciences of the USSR.
During a new expedition in 2004, Dmitri Kachalin recovered about 50 kg of new material. Remarkably, many of the new specimens (about 20%) were found to contain olivine
crystals and so revealed the silicated nature of the meteorite. The pallasitic structure was not discovered previously during studies on small metal-only sections of the original mass.
content. Before the discover of its pallasitic structure it had been classified as IIE anmalous coarse octahedrite. Seymchan is considered a stable and rust-resistant pallasite.
Pallasite
A pallasite is a type of stony–iron meteorite.-Structure and composition:It consists of cm-sized olivine crystals of peridot quality in an iron-nickel matrix. Coarser metal areas develop Widmanstätten patterns upon etching...
meteorite
Meteorite
A meteorite is a natural object originating in outer space that survives impact with the Earth's surface. Meteorites can be big or small. Most meteorites derive from small astronomical objects called meteoroids, but they are also sometimes produced by impacts of asteroids...
found in 1967 in Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
.
History
It was found in the dry bed of river Hekandue, a left tributary of river Jasačnaja in the Magadan districtMagadan Oblast
Magadan Oblast is a federal subject of Russia in the Far Eastern Federal District. Its administrative center is the city of Magadan....
, Russia
Russia
Russia or , officially known as both Russia and the Russian Federation , is a country in northern Eurasia. It is a federal semi-presidential republic, comprising 83 federal subjects...
, near the settlement of Seymchan
Seymchan (urban-type settlement)
Seymchan is an urban-type settlement and the administrative center of Srednekansky District of Magadan Oblast, Russia. Population: -Local geography:...
.
The main mass of 272.3 kg was found in June 1967 by the geologist F. A. Mednikov during a survey. The mass was a triangual shaped thumbprinted meteorite lying among the stones of the brook bed. A second specimen of 51 kg was found in October 1967 at a distance of 20 m from the first one by I. H. Markov with a mine detector 1967. The main mass was turned in to the Academy of Sciences of the USSR.
During a new expedition in 2004, Dmitri Kachalin recovered about 50 kg of new material. Remarkably, many of the new specimens (about 20%) were found to contain olivine
Olivine
The mineral olivine is a magnesium iron silicate with the formula 2SiO4. It is a common mineral in the Earth's subsurface but weathers quickly on the surface....
crystals and so revealed the silicated nature of the meteorite. The pallasitic structure was not discovered previously during studies on small metal-only sections of the original mass.
Composition and classification
Seymchan belongs to Main Group pallasites, but it is considered anomalous due to its high IrIridium
Iridium is the chemical element with atomic number 77, and is represented by the symbol Ir. A very hard, brittle, silvery-white transition metal of the platinum family, iridium is the second-densest element and is the most corrosion-resistant metal, even at temperatures as high as 2000 °C...
content. Before the discover of its pallasitic structure it had been classified as IIE anmalous coarse octahedrite. Seymchan is considered a stable and rust-resistant pallasite.