Sample No.: BTNA78002

Location: Bates Nunatak

Field No.: 325 and 326

Weight (gms): 4301.0

Meteorite Type: L6 Chondrite

Physical Description:

This specimen consists of two individual pieces that fit together. Nearly the entire sample is covered with thin, dull brown fusion crust (apparently weathered) that is dotted with black fusion crust. The fusion crust appears to have been physically removed from some small areas on all surfaces and an approximately 7.0 x 10.0 cm area on the S surface of the sample appears to have been broken away. The areas devoid of fusion crust are light grayish-green where they are not stained by iron oxidation. A few flecks of metallic phase minerals are discernible in these areas. The T surface of the meteorite has flow bands in the E-W direction and regmaglypts are visible on the B surface. The plane on which this specimen broke is very flat and is 90% iron oxide stained a reddish-brown. The areas not iron oxide stained are the same greenish-gray color seen on the exterior surfaces of the sample. Some small metallic mineral flakes are visible on these fracture surfaces. Dimensions: 20 x 12 x 14 cm.

Petrographic Description: Brian Mason

Two polished thin sections were examined, one from BTNA78002,3 and one from BTNA78002,6. They are identical in all respects and confirm the macroscopic identification of these as two pieces of a single meteorite. Chondrules are sparse and poorly defined, merging with the granular groundmass, which consists of olivine and pyroxene, with minor maskelynite and subequal amounts of nickel-iron and troilite. A little limonitic staining is associated with the nickel-iron grains. Microprobe analyses show olivine (Fa24) and orthopyroxene (Fs20) of uniform composition; the maskelynite has CaO (2.0%) appropriate to oligoclase composition, but has deficient and variable Na2O content (3.2-6.6%). The meteorite is classified as an L6 chondrite.