Sample No.:	LAR 06877
Location:	Larkman Nunatak
Field No.:	19048
Dimensions (cm):	7.0 x 6.0 x 3.0
Weight (g):	588.2
Meteorite Type:	Iron-IIIAB

Macroscopic Description: Tim McCoy
The meteorite has a brown surface indicative of oxidation. It exhibits a strongly convex upper surface typical of flight oriented specimens. On one end of the meteorite, the upper surface contacts a planar lower surface along a distinct terminal ridge. This planar lower surface measures ~5 x 3 cm and terminates along an irregular boundary. The remainder of the lower surface appears to be a later fracture surface, although that fracture likely occurred in the atmosphere judging from the smoothed nature and oxidized surface. On both the upper and lower broken surface, sets of parallel lines are observed, almost certainly reflecting the Widmanstätten pattern of this meteorite.

 

Thin Section (,2) Description: Tim McCoy
A longitudinal, lenticular-shaped slice measuring ~6 x 2.5 cm was examined prior to thin section preparation. The meteorite exhibits a continuous Widmanstätten pattern with long, thin (~0.5 mm width) kamacite lamellae. In polished section, the convex upper surface is observed to be bounded by a 100-200 µm fusion crust. A reheated α2 structure penetrates ~1 mm around the entire periphery of the sample. Kamacite lamellae range between ~300 and 500 µm in width and triangular to rectangular plessite fields reach 2 mm in width. A single 2 mm troilite inclusion contains an ~100 ?m chromite grain and is bounded by a similarly-sized schreibersite. A microprobe traverse across the section yielded 8.7 wt% Ni, 0.17 wt.% P and 0.51 wt.% Co, within the range for IIIAB irons (Yang and Goldstein, 2005, MAPS 40, 239). The meteorite is an iron, probably of group IIIAB.

Thin Section Images

Reflected Light LAR 06877

Lab Images