| Muonionalusta | |
|---|---|
| The Muonionalusta, on loan to the Prague National Museum in 2010. It is the largest meteorite ever exhibited in the Czech Republic. | |
| Type | IVA (Of) |
| Class | Octahedrite |
| Group | Iron |
| Structural classification | Fine Octahedrite |
| Composition | Ni, Ga, Ge |
| Country | Sweden |
| Region | Norrbotten |
| Observed fall | No |
| Found date | 1906 |
| Full slice (across 9.6cm) of the Muonionalusta, showing the Widmanstätten pattern. | |
The Muonionalusta is a meteorite classified as fine octahedrite, type IVA (Of). The first fragment of the Muonionalusta was found in 1906 in a 25 kilometres (16 mi) x 15 kilometres (9.3 mi) area approximately 140 kilometres (87 mi) north of the Artic Circle, in the Pajala district, Norbbotten, Sweden.[1] Around forty pieces are known today, some being quite large.
It was first described in 1910 as Muonionalusta, therefore named after the municipality of Muonio, by professor A. G. Högbom and studied in 1948 by Professor Nils Göran David Malmqvist.[2] The Munionalusta, probably the oldest meteorite known to man, marks the first occurence of stishivite in an iron meteorite.[1]
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Studies have shown it to be the oldest discovered meteorite impacting the Earth during the Quaternary period, about one million years ago. It is quite clearly part of the iron core or mantle of a planetoid, which shattered into many pieces upon its fall on our planet.[3] Since landing here this meteorite has experienced four ice ages. It was unearthed from a glacial moraine in the northern tundra. A strongly weathered surface covered with cemented facetted pebbles leaves no doubt that its sojourn on Earth has been long and dramatic.
New analysis of this strongly shock-metamorphosed iron meteorite has shown a content of 8.4% nickel and trace amounts of rare elements - 0.33% ppm gallium, 0.133% ppm germanium and 1.6 ppm iridium. It also contains the common minerals chromite, Daubreélite, schreibersite, Akaganéite and inclusions of troilite.[2] For the first time, analysis has proved the presence of a form of quartz altered by extremely high pressure - stishovite,[2] probably a pseudomorphosis after tridymite.