Sample No.: ALHA77214

Location: Allan Hills

Field No.: 77122798

Weight (gms): 2111.0

Meteorite Type: L3 Chondrite

Physical Description:

Specimen is angular with remnants of fusion crust on ~30%-of the exterior surface. Another ~30% of the meteorite may have previously been covered with fusion crust, but has been abraded away. The remaining portion of the sample is a fracture surface. The stone contains many fissures. Snow (ice?) was observed in several of the fissures when the meteorite was removed from cold storage. It ranges in color from brown through brownish-black, and has a weathering patina on all surfaces with the exception of the fracture surface. Some iron-oxide staining is apparent on exterior surface, however, the material adjacent to the fissures and the fracture surface are most severely iron oxide stained. A number of chondrule-like structures are obvious. Chipping revealed that the meteorite is very weathered and friable along fracture surfaces. This is not a complete specimen. Its approximate measurements are 16 cm x 9.5 cm.

Petrographic Description: Elbert King

This section is rather badly weathered with much of the metal oxidized to hematite. Some of the large hematite areas are colloform. However, the narrow end of the slide is much more weathered than the wider end, giving some hope that the deep interior of the stone may be much fresher. Troilite is abundant and outlines the margins of many chondrules. Chondrule margins are sharply distinguishable from the fine-grained matrix. At least two chondrules contain fresh pinkish-brown glass that shows strain isogyres in crossed polarizers. Most chondrules appear to be fluid drop chondrules, and some are broken or are only small portions of their original volumes as judged from their radii of curvature. Some chondrules, which range in size to more than 4 mm in maximum diameter, contain large euhedral-olivine crystals and some large euhedral olivine and pyroxene crystals occur as individual crystals with no apparent crystallized liquid attached. A number of the fluid drop and lithic chondrules appear to be surrounded by fine-grained troilite-rich, dark rims or rinds, but the exact nature of the rims is difficult to distinguish because of the weathering. The largest chondrule shows interesting poikilitic textures, with pyroxene enclosing smaller round grains of olivine and another pyroxene (?). The rim of this chondrule is of low interference color pyroxene (?), large patches of which are in optical continuity. It deserves detailed study, particularly microprobe analysis, and may be a peculiar lithic fragment. Most other chondrule textures appear to be normal for low petrologic type ordinary chondrites. One troilite-rich, fine-grained lithic fragment is obvious (~1.9 mm maximum dimension) that deserves detailed study. Two small fragments of finely devitrified glass are present, ranging to 0.2 mm. The matrix in this stone is very difficult to see because of the weathering. It appears dark to opaque, very fine-grained and troilite-rich.