acquired some very nice pieces of the NWA 4734 Lunar meteorite. This
meteorite is classified as a Mare Basalt (Monzogabbro). It is extremely
beautiful, very fresh, and a very rare type. The meteorite was
completely covered with glossy black fusion crust.
History: Two pieces were purchased from nomads in Erfoud, Morocco in
October 2006 and February 2007.
Physical characteristics: A. Habibi purchased two pieces, with a total
mass of 477 g, in Rissani, Morocco, and several other pieces of the same
stone totaling 895 g are with M. Oumama in Rissani, Morocco. Dull
black/brown fusion crust nearly complete and inside slightly tarnished
where absent. It is a gray, coarse grained, pristine magmatic rock
consisting of millimeter-sized phenocrysts, mainly of pyroxene and
Petrography: (A. Jambon, O. Boudouma and D. Badia, UPVI). The texture is
best described as shergottite-like. Pyroxene grains are highly fractured
while plagioclase laths, partly transformed to maskelynite, are only
affected by a small number of fractures. Silica and silica-feldspar
glass are minor components. A few patches of impact melt are also
observed. Ilmenite, baddeleyite, zirconolite, tranquilityite, pyrrhotite
and metal. Fayalite associated with silica probably results from the
dissociation of iron rich pyroxene. Modal mineralogy (vol %): Cpx 50,
Plagioclase + Kspar 32, silica + glass 7.5, opaques (ilmenite,
Ti-magnetite, pyrrhotite) + fayalite 7, voids + fractures 3.
Geochemistry: Mineralogy by EMP and SEM. (Trace and major element
analyses ICP-MS and ICP-AES, J-A Barrat, UBO). Pyroxene grains are
complexly zoned (En65Fs21Wo13 to En2Fs83Wo15; FeO/MnO = 78 [average]). A
few compositions correspond to pyroxferroite. Plagioclase is normally
zoned from An75-91 (average An89) with minor olivine (Fa80-95).
Chondrite normalized REE pattern with an enrichment of 53 (La) to 40 (Yb).
Trace element pattern with negative anomalies of Sr and Eu. Interstitial
glass is high in silica (75 wt%) and contains microcrysts of K-feldspar
with a significant celsian component. The chemistry, major and trace
elements, is identical to NWA 032-479-773 and LAP
02205-02224-02226-02234-02436-03632. The texture is very similar to that
of the LAP specimens. The very low abundance of olivine and the relative
abundance of silica in NWA 4734 are the main differences beside the
grain size and the slightly different composition of the major phases.
Classification: Achondrite (lunar); extensive shock.
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Northwest Africa 4734 - Lunar Meteorite