HEDJAZ

Stony

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CHONDRITE

ORDINARY

H-L-LL

L

3.7-6

SAUDI ARABIA

1910

Unequilibrated/Equilibrated Ordinary Chondrite Breccia L 3.7-6..

PETROGRAFIA:

The main constituents of the Hedjaz meteorite are olivine, pyroxene, plagioclase, troilite, kamacite and taenite. Small amounts of accessory chromite, merrilite and ilmenite are also present. Olivine is mainly equilibrated, but pyroxene is much more variable and small amounts of glass are present. The last characteristics are those found in unequilibrated chondrites. But Hedjaz is not a normal unequilibrated chondrite, which has never experienced substantial metamorphism, as it presents lithologies referring to petrographic types 4, 5 and 6. The textures and variability of the FeNi metal are equally prominent - kamacite and taenite occur separately , together and occasionally with troilite. Dark veins and other shock characteristics are observable. Thus, Hedjaz is a brecciated mixture of unequilibrated, partially equilibrated and equilibrated L chondrites and clasts. Source: www. mindat.org

GEOQUÍMICA:

The analysis by electron probe performed on pyroxenes found the composition range of Wo0-7 En70-90 Fs10-23. Clinopyroxene is relatively rare and occurs as thin line lamellae, which could not be well analyzed. Diopside is an accessory, occasionally at the edges of orthopyroxenes. The other main mineral, olivine, occurs in the chondrules, but is found mainly in the matrix. The analyzes showed that all are remarkably constant in the composition Fa23.4 ± 0.51% PMD 2.2. In the FeNi phase, the nickel content found was 5.4% in kamacite, where the highest Ni value found in taenite (probably tetrataenite) was 52.4%. The kamacite contained an average of 0.74% Co (% PMD 8.1). Source: Fredriksson & Fredriksson (1986).

CLASSIFICAÇÃO:

The Hedjaz meteorite has been studied in detail and with a chemical basis, having 22.1% total Fe, 9% metallic Fe, 1.3% Ni and equilibrated composition of olivine (Fa23-24), can be classified as group L chondrite. However, petrographically Hedjaz is quite heterogeneous and contains characteristics of types 3, 4, 5 and 6. In fact, Hedjaz, as a complex breccia and shows no evidence of metamorphic equilibrium after the accretion phase. For more information, the link to the source article is available at http://adsabs.harvard.edu/full/1986Metic..21..159F. Source: Fredriksson & Fredriksson (1986).

CLASSIFICADORES:

Not reported by the Meteorical Bulletin database. The first description was carried out by J. Couyat of the Natural History Museum in Paris in 1912, together with Pisani's chemical analyzes. Other authors have contributed over the years, but Kraut & Fredriksson (1971) reported a new chemical analysis in which he classified Hedjaz as L 3-6. Source: Fredriksson & Fredriksson (1986).

HISTÓRIA:

The exact date and location of the Hedjaz meteorite fall is unknown. However, according to the Bedouins (Couyat, 1912), the meteorite fell on a spring night in 1910, not far from Dhaba, in Madian (Saudi Arabia), splitting into four fragments that spread over a distance of 15 km. Source: Fredriksson & Fredriksson (1986).

Todas as informações que não possuírem fonte especifica, foram extraídas do Meteoritical Bulletin Database.

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