Seymchan (meteorite)

Meteorite
Name= Seymchan


Image_caption= An olivine-free portion of Seymchan
Image_width=
Type= Stony-iron
Class= Pallasite
Group= Main Group Pallasite
Structural_classification= Coarse octahedrite
Composition= 9.15% Ni, 24.6 ppm Ga, 68.3 ppm Ge, 0.55 ppm Ir.
Shock=
Weathering=
Country= Russia
Region= Magadan Oblast
Lat_Long= coord|62|54|N|152|26|E|display=inline,title [ [http://tin.er.usgs.gov/meteor/metbull.php?sea=Seymchan+&sfor=names&ants=&falls=&stype=contains&lrec=50&
Seymchan] ]
Observed_fall= No
Fall_date=
Found_date= June 1967
TKW= about 380 kg


Image2_caption=

Seymchan is a pallasite meteorite found in 1967 in Russia.

History

It was found in the dry bed of river Hekandue, a left tributary of river Jasačnaja in the Magadan district, Russia.

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 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%) [ [http://www.meteoritestudies.com/protected_SEYMCHAN.HTM Meteorites Studies: Seymchan] ] 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.

Composition and classification

Seymchan belongs to Main Group pallasites, but it is considered anomalous due to its high Ir content [van Niekerk, 2007] . 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.

pecimens

Due the heterogeneous structure of Seymchan, there are two types of specimens: "with" or "without" olivine crystals.

Notes

See also

* Meteorite
* Pallasite

External links

* [http://www.marmet-meteorites.com/id9.html Dmitri Kachalin and wife Natalia the finders of the Seymchan, anom. pallasite]
* [http://tin.er.usgs.gov/meteor/metbull.php Meteoritical Bulletin Database]