Sample No.: ALHA78084

Location: Allan Hills

Field No.: 270

Weight (gms) 14280.0

Meteorite Type: H3 Chondrite

Physical Description:

This is a complete specimen with splotchy brown and black fusion crust covering the entire meteorite. Several large fractures penetrate the interior of the stone. A thin white deposit was evident along some of these cracks after the meteorite was dried. Many light colored rounded and irregular inclusions are apparent on the cut faces, some as large as 4 mm in diameter. Metal is visible though most of the metal have halos around them, giving the cut faces a marbled look of small fresh areas and large oxidized areas.

Petrographic Description: Brian Mason

The section shows a close-packed aggregate of chondrules, 0.3-1.2 mm in diameter, and a few angular enclaves (some are chondrule fragments), in a minor amount of fine-grained matrix. A wide variety of chondrules is present, the commonest being porphyritic olivine and olivine-pyroxene with interstitial glass; some of the glass is brown and transparent, but much of it is turbid and partly devitrified. The pyroxene is polysynthetically twinned clinobronzite. The matrix contains a considerable amount of fine-grained nickel-iron and a lesser amount of troilite. Weathering is extensive, with veins and patches of brown limonite throughout the section. Microprobe analyses show olivine of rather uniform composition, averaging Fa18, and pyroxene of variable composition, Fs8-24, average Fs13. The mean composition of the olivine and the amount of nickel-iron indicate H group and the meteorite is classified as an H3 chondrite.