Sample No.: ALHA81024

Location: Allan Hills

Field No.: 1510

Weight (gms): 797.7

Meteorite Type: L3 Chondrite

Physical Description: Carol Schwarz

This angular specimen is covered by black blistery fusion crust; some areas are reddish-brown. Several deep fractures penetrate the specimen. The interior exposed in chipping is reddish-brown and appears to be extremely weathered. Dimensions: 10 x 8 x 6.5 cm.

Petrographic Description: Brian Mason

The section shows a close-packed aggregate of chondrules, up to 1.5 mm across; a variety of types is present, including porphyritic olivine, barred olivine, granular olivine and olivine-pyroxene, and fine-grained pyroxene. Much of the pyroxene is polysynthetically twinned clinobronzite. Some intergranular glass within the chondrules is pale brown and transparent, but commonly is turbid and partly devitrified. Minor amounts of nickel-iron (largely altered to brown limonite) and troilite are present in the matrix. Olivine and pyroxene have variable composition. Olivine composition ranges from Fa3 to Fa28, with a mean of Fa19 (% mean deviation FeO is 34). Pyroxene composition ranges from Fs2 to Fs24, with a mean of Fs10 (% mean deviation FeO is 79). Transparent chondrule glass has the following mean composition (weight per cent): SiO2 63.3, Al2O3 22.5, FeO 0.9, MgO 0.2, CaO 0.2, K2O 3.3, Na2O 8.8, TiO2 0.8, MnO 0.03; this composition is close to anorthoclase. The texture and the variable mineral compositions are that of type 3, and the amount of metal suggests L group, hence the meteorite is tentatively classified L3. It is possibly paired with ALHA77011 and many other L3 chondrites from the Allan Hills.