Name: Larkman Nunatak 06869 This is an OFFICIAL meteorite name. Abbreviation: LAR 06869 Observed fall: No Year found: 2006 Country: Antarctica [Collected by US Antarctic Search for Meteorites program (ANSMET)] Mass: 18.4 g
Macroscopic Description: Kathleen McBride The exteriors of these meteorites range from rough brown/black fusion crust to smooth black exterior. The interiors have dark gray to black matrix with evaporites, some are rusty and very hard and have small light colored inclusions.
Thin Section (,2) Description: Tim McCoy, Linda Welzenbach and Cari Corrigan The sections exhibit a mixture of fine-grained mixture of olivine, calcic pyroxene and plagioclase with individual grains reaching a few hundred microns, but most grains of apparently finer grain size, perhaps owing to shock. Shock veins cross cut the sections forming a network. Vesicular, melted fusion crust was only present on one of the sections examined. Oxides and sulfide are relatively common to abundant. Olivine is Fa34, pyroxene is an Al-bearing (2-4 wt.% Al2O3) augite of Fs12Wo50, and a small number of plagioclase analyses suggest considerable heterogeneity An43-88Or0-8. Iron oxide is abundant and appears to be magnetite with significant Fe3+ present (based on low totals), as well as 5 wt.% Cr2O3 and 2 wt.% Al2O3. Sulfide is an Fe,Ni sulfide, likely pentlandite. The meteorites are strongly shocked and metamorphosed chondrites, probably CK6.
Oxygen Isotopic Analysis: D. Rumble, Geophysical Laboratory, Carnegie Institution of Washington Magnetic fractions (magnetite) were analyzed (after ultrasonication in dilute HCl), which is important because an analysis of silicates will almost certainly give heavier small delta values.
Oxygen isotopic analyses of two small (2-5 mg) pieces yielded the following results:
18.4 g
