Sample No.: ALHA78038

Location: Allan Hills

Field No.: 278

weight (gms): 363.0

Meteorite Type: LL3 Chondrite

Physical Description:

This angular sample is approximately 12 x 5 x 5 cm. and appears shiny and reddish-brown due to weathering and staining by iron oxidation. Several fractures penetrate deeply into the sample. One small remnant patch of shiny black fusion crust remains on the B surface. During processing the sample fell apart and revealed no unoxidized material.

Petrographic Description: Brian Mason

The section shows a close-packed aggregate of chondrules, 0.3 - 2.7 mm in diameter, and a few angular enclaves (some are chondrule fragments) in a minor amount of dark fine-grained matrix. A wide variety of chondrules are present, the commonest being granular olivine and olivine-pyroxene, porphyritic olivine, and fine-grained pyroxene, Most of the pyroxene is polysynthetically twinned. Many of the chondrules have dark rims. Troilite is present in minor amounts in the matrix. Weathering is extensive, the section being rimmed and veined with brown limonite, and little nickel-iron remains. Microprobe analyses show olivine ranging from Fa4 to Fa9, with a mean of Fa22; pyroxene ranges from Fs2 to Fs19 , with a mean of Fs8 and CaO ranging from 0.1 to 1.3 weight percent. The low content of nickel-iron and troilite suggests LL group, and the meteorite is tentatively classified as an LL3 chondrite.