from The
Meteoritical Bulletin,
no. 93, Meteoritics & Planetary Science 43,
571-632 (2007)
Northwest Africa 5000
Morocco
Find: July 2007
Achondrite (lunar, feldspathic breccia)
History: Found in July 2007 in
southern Morocco and provided to Adam Hupé in October 2007 by a Moroccan
dealer.
Physical characteristics: A single, large cuboidal stone (11.528
kg) with approximate dimensions 27 cm × 24 cm × 20 cm. One side
(which appears to have been embedded downward in light brown mud) has preserved
regmaglypts and is partially covered by translucent, pale greenish fusion crust
with fine contraction cracks. Abundant large beige to white, coarse-grained
clasts up to 8 cm across (some of which have been eroded out on exterior surfaces
of the stone, likely by eolian sand blasting) and sparse black, vitreous clasts
up to 2 cm across (containing irregular small white inclusions) are set in
a dark gray to black, partially glassy breccia matrix. One partially eroded
clast exposed on an exterior surface contains both the coarse grained beige
lithology and the more resistant black, vitreous lithology in sharp contact.
Petrography: (A. Irving and S. Kuehner, UWS) Almost
monomict fragmental breccia dominated by Mg-suite olivine gabbro clasts
consisting predominantly of coarse-grained (0.5-2 mm) calcic plagioclase,
pigeonite (some with fine exsolution lamellae), and olivine with accessory
merrillite, Mg-bearing ilmenite, Ti-bearing chromite, baddeleyite, rare
zirconolite, silica polymorph, K-feldspar, kamacite, and troilite. Some
gabbro clasts have shock injection veins composed mostly of glass containing
myriad fine troilite blebs and engulfed mineral fragments. Black, vitreous
impact melt clasts consist of sporadic, small angular fragments (apparently
surviving relics) of gabbro and related mineral phases in a very fine
grained, non-vesicular, ophitic-textured matrix of pigeonite laths (up
to 20 microns long × 2 microns wide) and interstitial plagioclase
with tiny spherical grains of kamacite, irregular grains of schreibersite
and rare troilite.
Mineral composition and geochemistry: Gabbro clasts:
plagioclase (An96.1-98.0Or<0.1), pigeonite (Fs32.0-64.5Wo6.7-13.1;
FeO/MnO = 51.1-62.0), olivine in different clasts range from Fa23.9-24.2,
Fa40.4 to Fa58.8 (with FeO/MnO = 81-100), chromite [(Cr/(Cr + Al) = 0.737,
Mg/(Mg + Fe) = 0.231, TiO2 = 5.9 wt%], ilmenite (4.1 wt% MgO). Bulk composition:
(R. Korotev, WUSL) INAA of 6 subsamples gave mean values of 5.3 wt% FeO
and 0.4 ppm Th.
Classification: Achondrite (lunar, feldspathic breccia).
Specimens: A total of 40.2 g of sample, two polished mounts and one large
polished
thin section are on deposit at UWS. AHupé hold the main mass. |
