Northwest Africa NWA 10404
views of unnamed 91
credit: by Mohamed Aid)
intriguing view of NWA 10404, with a clast of green impact glass exposed.
On the Moon, glass formed from feldspathic rocks (low iron) is often green
because the concentration of chromium is high even in feldspathic rocks
(several hundred parts-per-million).
On Earth, chromium (Cr) is added to glass to make it green.
credit: Darryl Pitt)
large sawn face of NWA 10404. Click on image for enlargement.
credit: Randy Korotev)
sides of a slice of unnamed 91. The vesicularity is evident here. Click on
image for enlargement.
credit: Randy Korotev)
The Meteoritical Bulletin, No.
Purchased: 2015 May, Ouarzazate, Morocco
Mass: 229 g, 1 piece
meteorite (feldspathic breccia)
History: Purchased by
Darryl Pitt in May 2015 from a dealer in Ouarzazate,
Physical characteristics: A single
stone (229 g) lacking fusion crust. Interior slices exhibit angular mineral
clasts plus rounded colorless, brownish and greenish glassy objects in
gray, partly vesicular matrix
Petrography: (A. Irving
and S. Kuehner, UWS) Vitric
fragmental breccia composed of angular to rounded lithic clasts plus
mineral clasts of anorthite, olivine, pigeonite, orthopyroxene, subcalcic
augite, augite and rare Ti-chromite, troilite and taenite in a partly
vitreous matrix. Some lithic clasts are fine grained, plagioclase-phyric
crystalline lithologies, but many consist of partly-devitifried
glass with bulk compositions intermediate between those of anorthite,
olivine and low-Ca pyroxene. The latter consist of isotropic cores
(colorless to pale brown in thin section) mantled by aggregates rich in
polycrystalline, spherulitic birefringent
crystallites within zones parallel to clast margins and constituting ~50%
of clast volumes.
Geochemistry: Olivine (Fa26.4;
Fa47.2, FeO/MnO = 77-84, N = 2), orthopyroxene (Fs37.6Wo3.2,
FeO/MnO = 64), pigeonite (Fs21.1-25.9Wo15.5-11.3,
FeO/MnO = 59-60, N = 2), subcalcic augite (Fs21.9Wo32.2,
FeO/MnO = 51), augite (Fs20.0Wo37.9, FeO/MnO = 46),
plagioclase (An96.1-97.0Or0.0, N = 3). Bulk
composition (R. Korotev, WUSL) INAA of subsamples gave the following mean
abundances (in wt.%) FeO 3.8, Na2O 0.36; (in ppm) Sc 6.8, La
4.2, Sm 2.0, Eu 0.83, Yb 1.5, Lu 0.21, Th 0.74.
(feldspathic vitric regolithic breccia).
Specimens: 20.61 g
including one polished thin section at UWB; main mass with DPitt.
a unique and unusually glassy and vesicular.
R. L. and Irving A. J. (2016) Not quite
keeping up with the lunar meteorites – 2016. 47th Lunar and Planetary
Science Conference, abstract no. 1358.
S. M., Wittmann A., Korotev R. L., Carpenter P., Macke R. J., Britt D. T.,
Irving A. J., and Pitt D. (2016) Petrologic,
chemical and physical characterization of unique lunar vitric regolith
breccia Northwest Africa 10404. 47th Lunar and Planetary Science
Conference, abstract no. 2246.
Will P., Maden
C., and Busemann H. (2016) Noble gases in recently found hot and
cold desert lunar meteorites (abstract). 79th Annual Meeting of
the Meteoritical Society, abstract no. 6548.
A., Korotev R. L., Kuehner S. M., and Irving A. J. (2016) The origin
and processing of magnesian glass in lunar meteorite Northwest Africa 10404
(abstract). 79th Annual
Meeting of the Meteoritical Society, abstract no. 6025.
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