Sample No.: ALH84200; 84220; 84235

Location: Allan Hills

Weight (g): 8.5; 8.4; 6.0

Field No.: 2538;2504;2378

Dimensions (cm): 3x1x1; 2x1.5x1.5; 2x2x0.8

Meteorite Type: E4 Chondrite

Macroscopic Description: Roberta Score

Very little fusion crust remains on these fragments. Part of ALH84200 is extensively oxidized and crumbles easily when handled. Other areas are black and contain inclusions that are <1 mm in size. ALH84220 and 84235 are extremely weathered; no features are visible.

Thin Section (ALH84200,2; 84220,2; 84235,2) Description: Brian Mason

These meteorites are identical in all respects and are probably paired. Chondrules and chondrule fragments are abundant, but are usually small (ranging up to 0.6 mm across, although a few are larger); they consist of fine-grained to coarsely granular pyroxene. The matrix consists of small pyroxene grains and opaque material (mostly nickel-iron with some sulfides). The meteorites are considerably weathered, with brown limonitic staining throughout the sections. Microprobe analyses show pyroxene compositions ranging from Fs0.6 to Fs4.0, with a mean of Fs1.8. The nickel-iron contains 2.3% Si. The meteorites are enstatite chondrites, and since most of the pyroxene is polysynthetically twinned clinoenstatite, they are classified E4. They closely resemble ALH84254, ALH82132, and some other ALH E4 chondrites, and the possibility of pairing should be considered.