Sample Petrographic Description
Sample Number | LAR 12248 |
Newsletter | 36,2 |
Location | Larkman Nunatak |
Field Number | 23937 |
Dimensions (cm) | 5.0 x 4.5 x 3.0 |
Weight (g) | 113.45 |
Original Classification | Diogenite |
Pairing | LAR 12248; LAR 12320; |
Mineral Composition (%Fa & %Fs) | |
Ferrosilite (mol%): 29 | |
Weathering | |
B | |
Fracturing | |
A/B | |
Macroscopic Description - Kathleen McBride, Cecilia Satterwhite | |
The exterior surfaces have black/brown patches of fusion crust with polygonal fractures. Exposed areas without fusion crust are yellow to crème colored matrix with some gray patches. The interior matrices are fine grained, tan to weathered yellow-ochre in color, with a few darker inclusions. | |
Thin Section Description (,2) - Cari Corrigan, Linda Welzenbach | |
These sections are similar enough that one description will suffice. The sections show a groundmass of coarse (up to 1.5 mm) comminuted pyroxene, with minor plagioclase and SiO2. Plagioclase also exists as individual rounded grains. Both sections contain a pervasive porosity that gives them a strange, mottled appearance. In some areas, large relict pyroxene grains (up to 1 cm) are present (some still exhibiting exsolution), but are still mosaicized and overprinted by porosity. This gives the sections the appearance of being brecciated but without strong clast boundaries. All silicates are mosaicized. Pyroxenes are Fs14-31. Feldspars are An92-94Or0.1. The Fe/Mn ratio of the pyroxene is ~27-28. The meteorites appear to be diogenites. |
Antarctic Meteorite Images for Sample LAR 12248 | ||||
Lab Photo(s) : | ||||
Antarctic Meteorite Images for Sample LAR 12248 | ||||
Thin Section Photo(s) : | ||||