Sample No.:	LAR 06876
Location:	Larkman Nunatak
Field No.:	19352
Dimensions (cm):	8.0 x 5.5 x 3.5
Weight (g):	475.3
Meteorite Type:	Iron-IAB

Macroscopic Description: Tim McCoy
The meteorite is a somewhat irregularly shaped mass of ~8 x 5.5 x 3.5 cm. One surface is relatively smooth, with numerous small (1-2 mm) pits and large (1-2 cm) and occasional larger (~5 mm diameter), shallow pits. The opposite surface is highly-irregular in shape, with larger (~5 mm) deep pits.

 

Thin Section (,2) Description: Tim McCoy
A longitudinal slice measuring ~5 x 2.5 cm was examined prior to thin section preparation. The slice exhibits a prominent reheated α2 structure around the entire margin, reaching to a depth of up to 3 mm. The section includes inclusions of troilite, silicates and likely graphite that reach up to 1.5 cm in maximum dimension. The meteorite exhibits a Widmanstätten pattern indicative of formation from a single austenite crystal and with kamacite bandwidths of ~1.5-2 mm. Examination of the polished thin section reveals polyminerallic inclusions of olivine (Fa₅), low-Ca pyroxene (Fs₆), high-Ca pyroxene (Fs₃), plagioclase, metal, troilite, graphite, schreibersite and rare chromite. No fusion crust or heat-altered zone was present. The metallic host contains poorly-defined, short kamacite lamellae that exceed 0.5 mm in width. A microprobe traverse revealed an average composition of 7.8 wt.% Ni, 0.06 wt.% P and 0.57 wt.% Co. The low P value likely reflects the exsolution of schreibersite. The meteorite in an iron, probably of group IAB.

Thin Section Images

Reflected Light LAR 06876

Lab Images