Sample No.: ALHA77155

Location: Allan Hills

Field No.: Y78010307

Weight (gms): 305.3

Meteorite Type: L6 Chondrite

Physical Description:

This sample is very rough on the exterior. The knob-like surface relief features are weathered orangish-brown on their tops and commonly reveal more less-weathered (light gray) material on their sides. No fractures were noted. The patch of black fusion crust (.5x2 cm) is preserved on the B surface. The stone is 9.0x4.5x4.5 cm and is rounded on the edges. The E surface is slightly more angular than the other surfaces, possibly representing a fracture surface. When the meteorite was cleaved, a non-weathered interior was exposed. A few halos of iron-oxidation were observed around light colored inclusions. A small area of darker gray material is present close to the N side of the sample on both the E and W butt-ends.

Petrographic Description: Brian Mason

In thin section chondrules are sparse and tend to merge with the granular groundmass; chondrule types include porphyritic and barred olivine with interstitial devitrified glass, and fine-grained pyroxene. Plagioclase is present in minor amounts, as anhedral untwinned grains. Accessory whitlockite was identified with the microprobe. Opaque minerals include minor amounts of nickel-iron and troilite, and accessory chromite. Limonitic staining is prominent around the nickel-iron grains. Microprobe analyses gave the following mineral compositions: olivine, Fa24; orthopyroxene, Fs20; plagioclase, An10.