Skapades av meteorit

Siljansringen

Siljansringen i Dalarna är Europas största nedslagskrater (astroblem), med en diameter på cirka 52&#;km.

Kratern skapades då en meteorit med en diameter av ca 5&#;km[1] slog ned och träffade jordens yta under devon för cirka [2] eller [3] miljoner år sedan. Astroblemets kanter bildar en cirkel av lägre liggande områden, som idag innehåller många insjöar, varav Siljan är den största. Andra sjöar i Siljansringens kanter är Orsasjön, Skattungen och Oresjön. Nedslagets effekter syns också tydligt i berggrunden i området då de ordoviciska och siluriska bergarterna ligger som en ring i området.

Fyndigheter

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Det har ställts i utsikt och finns fortfarande förhoppningar om att marken döljer oljefyndigheter och naturgas som kan vara värda att exploatera. Gasen skulle ha kunnat hållas kvar under det lock av smält berg som nedslaget förorsakade. Fyndigheterna skulle härröra från olja av icke-biologiskt ursprung enligt teorier av sovjetiska forskare och kosmologen med mera Thomas Gold ().

På talet bedrev företaget Dala Djupgas AB provborrningar i området utan önskat resultat. bedriver företaget Igrene AB liknande undersöknings

  • skapades av meteorit

    • Muonionalusta

    Octahedrite meteorite

    The Muonionalusta meteorite (Finnish pronunciation:[ˈmuo̯nionˌɑlustɑ], Swedish pronunciation:[mʉˈǒːnɪɔnalːɵsta])[1] is a meteorite classified as fine octahedrite, type IVA (Of) which impacted in northern Scandinavia, west of the border between Sweden and Finland, about one million years BCE.

    The first fragment of the Muonionalusta meteorite was found in near the village of Kitkiöjärvi.[2] Around forty pieces are known today, some being quite large. Other fragments have been found in a bykilometre (&#;mi ×&#;&#;mi) area in the Pajala district of Norrbotten County, approximately kilometres (87&#;mi) north of the Arctic Circle.

    The meteorite was first described in by Professor A. G. Högbom, who named it after the nearby place Muonionalusta on the Muonio River. It was studied in by Professor Nils Göran David Malmqvist.[3] The Muonionalusta meteorite, probably the oldest known meteorite ( ± billion years),[4] marks the first occurrence of stishovite in an iron meteorite.

    The mineral muonionalustaite, a hydrated nickel chloride, was first found as a weathering product from a meteori

    Meteorite

    Solid debris from outer space that hits a planetary surface

    This article is about debris from space that survives impact with the ground. For other uses, see Meteorite (disambiguation).

    A meteorite is a rock that originated in outer space and has fallen to the surface of a planet or moon. When the original object enters the atmosphere, various factors such as friction, pressure, and kemikalie interactions with the atmospheric gases cause it to heat up and radiate energy. It then becomes a en rymdsten som brinner upp när den kommer in i jordens atmosfär and forms a eldsfär, also known as a shooting star; astronomers call the brightest examples "bolides". Once it settles on the larger body's surface, the en rymdsten som brinner upp när den kommer in i jordens atmosfär becomes a meteorite. Meteorites vary greatly in storlek. For geologists, a bolide is a meteorite large enough to create an impact crater.[2]

    Meteorites that are recovered after being observed as they transit the atmosphere and impact Earth are called meteorite falls. All others are known as meteorite finds. Meteorites have traditionally been divided into three broad categories: stony meteorites that are rocks, mainly composed of silicate minerals; iron meteorites that are largely composed of ferronickel