Stony-iron meteorite
| Stony-iron meteorite (siderolites) | |
|---|---|
| — Type — | |
 A slice of the Esquel meteorite showing the mixture of meteoric iron and silicates that is typical of this division. | |
| Type | Stony-iron |
| Subgroups |
|
| Composition | Meteoric iron (kamacite, taenite & tetrataenite); silicates |
| Total known specimens | 95 pallasites, 183 mesosiderites (278 Total) |
Stony-iron meteorites or siderolites are meteorites that consist of nearly equal parts of
stony meteorites, that are mostly silicates, and the iron meteorites, that are mostly meteoric iron.[1]
Stony-iron meteorites are all differentiated, meaning that they show signs of alteration. They are therefore
achondrites
.
The stony-irons are divided into
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
References
- ISBN 978-0521587518.
- .
- ^ F. Heide, F. Wlotzka: Meteorites, Messengers from Space. Springer Verlag 1985.
- ^ Karl K. Turekian. Meteorites, comets, and planets,112