Stony-iron meteorite

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Stony-iron meteorite (siderolites)
  Type  
Esquel.jpg
A slice of the Esquel meteorite showing the mixture of meteoric iron and silicates that is typical of this division.
Type Stony-iron
Subgroups
  • Pallasite
  • Mesosiderite
CompositionMeteoric iron (kamacite, taenite & tetrataenite); silicates
Total known specimens95 pallasites, 183 mesosiderites (278 Total)

Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of meteoric iron and silicates. This distinguishes them from the stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron. [1]

Contents

Stony-iron meteorites are all differentiated, meaning that they show signs of alteration. They are therefore achondrites.

The stony-irons are divided into mesosiderites and pallasites. Pallasites have a matrix of meteoric iron with embedded silicates (most of it olivine). [2] Mesosiderites are breccias which show signs of metamorphism. The meteoric iron occurs in clasts instead of a matrix. [3] [4]

They are in the top rank of all Meteorite classification schemes, usually called "Type".

Mineralogy

The meteoric iron of stony-irons is similar to that of iron meteorites, consisting mostly of kamacite and taenite in different proportions. The silicates are dominated by olivine. Accessory minerals that also include non-silicates are: carlsbergite, chromite, cohenite, daubréelite, feldspar, graphite, ilmenite, merrillite, low-calcium pyroxene, schreibersite, tridymite and troilite.

See also

Related Research Articles

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<span class="mw-page-title-main">Pallasite</span> Class of stony–iron meteorite

The pallasites are a class of stony–iron meteorite. They are relatively rare, and can be distinguished by the presence of large olivine crystal inclusions in the ferro-nickel matrix.

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<span class="mw-page-title-main">Iron meteorite</span> Meteorite composed of iron-nickel alloy called meteoric iron

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<span class="mw-page-title-main">Fukang meteorite</span> Pallasite meteorite found near Fukang, China

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<span class="mw-page-title-main">Mesosiderite</span> Class of stony–iron meteorites

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<span class="mw-page-title-main">Pallasovka (meteorite)</span> Pallasite meterorite found during 1990 in southern Russia

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<span class="mw-page-title-main">Seymchan (meteorite)</span>

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IIG meteorites are a group of iron meteorites. The group currently has six members. They are hexahedrites with large amounts of schreibersite. The meteoric iron is composed of kamacite.

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The Winona meteorite is a primitive achondrite meteorite. It is the type specimen and by far the largest meteorite of the winonaite group.

This is a glossary of terms used in meteoritics, the science of meteorites.

References

  1. McSween, Harry Y. (1999). Meteorites and their parent planets (Sec. ed.). Cambridge: Cambridge Univ. Press. ISBN   978-0521587518.
  2. Buseck, P.R. (1977). "Pallasite meteorites: mineralogy, petrology, and geochemistry". Geochimica et Cosmochimica Acta. 41 (6): 711–740. Bibcode:1977GeCoA..41..711B. doi:10.1016/0016-7037(77)90044-8.
  3. F. Heide, F. Wlotzka: Meteorites, Messengers from Space. Springer Verlag 1985.
  4. Karl K. Turekian. Meteorites, comets, and planets,112