Ordinary chondrite
Ordinary chondrites are the most frequently falling type of chondrites with 93.5% , which in turn are the most common meteorites .
They contain spherical inclusions of minerals , the chondrules , which usually consist of olivine and / or pyroxene . The chondrules represent primordial matter that condensed early from the solar nebula . In addition, the chondrites contain different levels of nickel iron from 5 to 20%.
Depending on the metal content, there is a classification into the following groups:
- H-Chondrite ( h igh metal ; iron content: 27.5 mass percent)
- L-Chondrite ( l ow metal ; iron content: 21.5 mass percent)
- LL-Chondrite ( l ow metal, l ow-iron ;: 18.5 mass percent of iron content)
The iron contents given refer to iron in metallic and oxidized form combined. An overview of the frequencies of other elements in the various chondrite classes can be found in Kallemeyn et al. .
In addition to the metal content-dependent classification, given the different appearance of the chondrites, a division into petrological classes from 1 to 6 is made, which reflects the development of the meteorites. Class 1 chondrites were not exposed to temperatures of more than 50 ° C during their development and remained largely unchanged. The meteorites of the higher classes were heated more strongly, which changed the crystalline structure. Class 6 chondrites were heated to over 950 ° C.
It is assumed that the different classes of chondrites originated in different zones of differentiated asteroids . Chondrites of class H3 were created on the surface, classes H4, H5, H6 and H7 in increasing depth.
| Group and class | Meteorite (s) as exemplary representative (s) | Remarks |
|---|---|---|
| H3 | Korra-Korrabes | |
| H4 | Kesen | |
| H4-5 | Blaubeuren | largest German chondrite, 30.67 kg |
| H5 | Gao-Guenie | |
| H6 | Peekskill | |
| H7 | NWA 4229 | |
| L4-6 | NWA 3009 | |
| L5 | Ghubara ; NWA 869 | |
| L6 | Benthullen |
Individual evidence
- ↑ MJ Múñoz-Espadas, J. Martínez-Frías, R. Lunar: Mineralogía, texturas y cosmoquímica de cóndrulos RP y PO en la condrita Reliegos L5 (León, España) . (PDF) In: Geogaceta . 34, 2003. 0213-683X, 35-38.
- ↑ Kallemeyn et al. (1989): Geochemistry of ordinary chondrites , Geochimica et Cosmochimica Acta, 1989, Vol. 53, pp. 2747-2767
- ↑ Largest German stone meteorite found in Blaubeuren. Retrieved July 16, 2020 .