| from The
Meteoritical Bulletin, No. 98, Meteoritics & Planetary Science
45, 1530–1551 (2010)
Shişr 166
Zufar, Oman
Found: 10 Apr 2008
Lunar (feldspathic melt breccia)
History: One stone was found by Luc Labenne in
the desert at night.
Physical characteristics: The 128.8-g meteorite
lacks an obvious fusion crust. The interior consists of a gray,
vesicular (up to 1.2 mm vesicles) melt matrix with rounded clasts
stained red by hematite. Many vesicles are filled with terrestrial
alteration products, including calcite, Ca-sulfate, and celestite.
Petrography: (R. Zeigler, WUSL) Melt matrix
dominated by plagioclase (average: An96.7Or0.2)
with intergrown of pigeonite (average Fs50Wo27;
Fe/Mn = 57), augite (Fs60Wo27; Fe/Mn = 48),
and olivine (Fo61; Fe/Mn = 102) in an apparent poikilitic
texture. Also present within the matrix are small grains of troilite,
Cr,Ti,Fe spinel (19 wt% TiO2, 25 wt% Cr2O3
, 23 wt% FeO), and ilmenite (5 wt% MgO, 1.5 wt% Cr2O3),
the latter two often intergrown. There are a few plagioclase clasts
(typically 0.2 mm, up to ~1 mm) and a few smaller olivine and pyroxene
clasts. Large veins of partially devitrified shock melt occur. Average
composition of the shock-melt vein: 43.7% SiO2, 0.24%
TiO2, 29.7% Al2O3, 4.3% FeO, 0.07%
MnO (Fe/Mn = 63), 4.0% MgO (Mg´ = 63), 16.8% CaO, 0.32 wt%
Na2O, and 0.03 wt% K2O.
Geochemistry: Bulk Chemistry: (R. Korotev, WUSL):
0.32% Na2O, 4.1% FeO, 7.9 ppm Sc, 140 ppm Ni, 1.2 ppm Sm.
Classification: Achondrite (lunar, impact-melt
breccia).
Specimens: 20.1 g are on deposit at WUSL,
the main mass is held by Labenne. |
