Northwest Africa 10986 (NWA 10986)

Grarat Zawi, Western Sahara

Find: 15 Nov 2015

Classification: Lunar meteorite

Physical characteristics: Total mass of the meteorite = 108.2 g and comprises several pieces, the larger weighing 80.5 g.

Petrography: (S. Roberts, UTenn) A highland impact-melt breccia with an unusually large amount of impact-generated glass. Displays multiple generations of melting and breccia-in-breccia formation. Brown to black devitrified glass swirls encompass heavily fragmented lithic clasts and mineral fragments. Lithic clasts represent 40% of the meteorite and have been partially to completely consumed during multiple impact and melting events. Clasts are heavily brecciated and range in size from 1.4 to 0.1 mm long. The clasts are plagioclase-rich with pyroxenes, olivines, spinel, and ilmenite in ophitic to poikilitic textures. Large broken plagioclase grains and small olivines and pyroxenes are found within the matrix. Lithic types range from FANs to Hi-Mg Suite rocks.

Geochemistry: Mineral compositions and geochemistry: Analyses were obtained from both lithic clasts and lose mineral fragments from within the breccia matrix. Plagioclase compositions average An_95.7±1.7 (N=43). Average pyroxene composition is Fs_36.6±13.3Wo_16.4±8.2 (N=73). Average olivine composition is Fs_30.9±12.9 (N=50). Fe/Mn ratios for pyroxenes are 58.7±8.1 (N= 73) and olivines are 98.8±8.7 (N=50).