Meteoritical Bulletin, No. 107
Northwest Africa 11898
Meteorite (feldspathic breccia)
History: Purchased in March 2018 by Dustin Dickens from a
meteorite dealer in Mali.
Physical characteristics: Several
identical appearing dark stones covered partially with a milky-green fusion
crust. Broken surface reveals a fragmental breccia with numerous white
feldspathic clasts set in a dark colored ground mass.
Petrography: (C. Agee, UNM) This meteorite is a breccia of
primarily feldspathic clasts, with lesser amounts of olivine and pyroxene
fragments. The shock melt composition has a very high alumina content,
vesicles occur throughout.
Geochemistry: (C. Agee, UNM) olivine Fa25.0±6.4,
Fe/Mn=90±5, n=8; pigeonite Fs31.0±3.6Wo8.1±3.6,
Fe/Mn=58±4, n=6; high-Ca pyroxene Fs22.3±3.7Wo35.0±4.7,
Fe/Mn=52±5, n=4; plagioclase An96.3±0.7Ab3.5±0.7Or0.2±0.0,
n=6; Shock melt (20 μm defocused electron beam, proxy for bulk
meteorite composition): SiO2=43.1±0.6, TiO2=0.12±0.03,
MgO=2.0±0.5, FeO=2.5±0.5, MnO=0.03±0.01, CaO=18.0±0.4, Na2O=0.36±0.01,
K2O=0.04±0.00 (all wt%), n=4.
Specimens: 21.6 g including
a probe mount on deposit at UNM, Dustin Dickens holds the main mass.