This specimen is a slice from the meteorite officially referenced by the Meteoritical Society under the name NWA 11954.
It belongs to the LL group, a type poor in metal (Magnetic succeptibility - χm=3.80)
The specificity of NWA 11954 is to be extremely primitive, reflecting the very high chemical heterogeneity of the pre-soler nebula.
Its heterogeneity, mainly the measurments of Fe/Mg ratio in both olivine and pyroxene (ferrous olivine, called fayalite, range 1.3 to 44.0 mol% - ferrous pyroxene, called ferrosilite, range Ferrosilite 2.5 to 15.1 mol%) show it belongs to the most primitive, pristine, of the chondrite type, the type 3 (NWA 11954 is LL3).
The heterogeneity of Cr2O3 in the ferrous olivine, 0.06-0.36 wt.%, mean 0.12±0.12 wt.%, allow to assign a subtype, the subtype 3.2.
Very close to the type 3.0, this rock record the conditions of the solar system when formed, about 4.56 billions years ago.
DESCRIPTION FROM THE METEORITICAL BULLETIN :
Petrography: (A. Irving and S. Kuehner, UWS) Well-formed chondrules (apparent diameter 690±450 µm) are set in relatively fine grained matrix containing stained metal, merrillite and chlorapatite.
Geochemistry: Olivine (Fa1.3-44.0, Cr2O3 in ferroan examples 0.06-0.36 wt.%, mean 0.12±0.12 wt.%, N = 7), orthopyroxene (Fs2.5-15.1Wo0.4-1.5, N = 3), clinopyroxene (Fs9.3-12.5Wo39.6-37.4, N = 2). Magnetic susceptibility log χ (× 10-9 m3/kg) = 3.80.
Classification: Ordinary chondrite (LL3). LL classification from magnetic susceptibility.
A type specimen, including one polished thin section at UWB (University of Washington, Box 353010 Seattle, WA 98195, United States); remainder with FKuntz.
Sent with signed certificat.
- Minéral principal / Nom météorite
- NWA 11954 - Primitice, hautement déséquilibré (Fayalite 1,3 à 44,0 mol% / Ferrosilite 2,5 à 15,1
- Forme minérale / Type météorite
- Météorite de Chondrite
- 11.63 g
- Origine (région / ville)
- Sahara occidental
- Origine (pays)