Sample No.: ALH85159

Location: Allan Hills

Weight (g): 11.0

Field No.: 2272

Dimensions (cm): 3 x 2.5 x 1

Meteorite Type: E4 Chondrite

Macroscopic Description: Roberta Score

The exterior is mostly covered with extremely weathered fusion crust. Chondrules are visible in the interior black matrix. Oxidation is moderate to heavy.

Thin Section (,3) Description: Brian Mason

Chondrules are relatively abundant, but are small, ranging up to 0.7 mm across; they consist of fine-grained to coarsely granular pyroxene (rare grains of olivine may be present) . The matrix consists largely of chondrule fragments and pyroxene grains, with a moderate amount of nickel-iron and sulfides. The meteorite is considerably weathered, with brown limonitic staining throughout the section. Microprobe analyses show pyroxene composition ranging from Fs0.3 to Fs1.8, with a mean of Fs0.9. The nickel-iron contains 2.2% Si. The meteorite is an enstatite chondrite, and since most of the pyroxene is polysynthetically twinned clinoenstatite, it is classed E4. It closely resembles ALH84254 and some other ALH E4 chondrites, and the possibility of pairing should be considered.