Sample No.: ALH84120

Location: Allan Hills

Weight (g): 129.0

Field No.: 1545

Dimensions (cm): 4x4.5x3

Meteorite Type: L3 Chondrite

Macroscopic Description: Roberta Score

Thirty percent of ALH84120 is covered with fusion crust. Areas devoid of fusion crust have a brownish-gray color. The interior of this unequilibrated chondrite is medium-gray in color and contains numerous light and dark gray rounded and irregular shaped inclusions. Oxidation is light and mainly appears as haloes around metal grains.

Thin Section (,3) Description: Brian Mason

The section shows an aggregate of chondrules (0.3-1.8 mm across) and chondrule fragments in a fine-grained matrix of olivine and pyroxene with minor amounts of nickel-iron and troilite. A variety of chondrule types is present; a barred chondrule has transparent pale brown glass between the olivine bars. Most of the pyroxene is polysynthetically twinned clinobronzite. Minor weathering is indicated by brown limonitic staining around metal grains. Microprobe analyses show most olivine of fairly uniform composition, averaging Fa22, but with a few more magnesian grains (CV FeO is 8). Pyroxene composition is more variable, Fs6-21. The meteorite is classified as an L3 chondrite, probably L3.8-3.9.