Northwest Africa 817

Morocco
Found 2000 December
Martian meteorite (nakhlite)

A 104 g stone was found in the desert of Morocco. Classification and analysis (V.  Sautter, MNHNP; J. Barrat and M. Lesourd, UAng; A. Jambon, UPVI; P. Gillet, ENSL; C. Göpel and J. Joron, IPGP): an unbrecciated, medium-grained, olivine-bearing clinopyroxenite with cumulate texture; consists of zoned, euhedral, subcalcic augite (Wo38–40 En38–27Fs24–34 and Fe/Mn = 39–31), olivine (zoned from Fa57 in cores to Fa86 in rims, with Fe/Mn = 54–43) with crystallized magmatic inclusions, and a three-component intercumulus mesostasis (glass including minute amounts of sulfide droplets, Ti-magnetite with unusual skeletal morphology containing ilmenite exsolution, and acicular pyroxene); mineral modes (vol%), pyroxene = 69, olivine = 15, mesostasis = 15, and Fe-Ti oxides = 1; alteration (probably pre­terrestrial) produced a hydrous ferrous silicate both in olivine and in the glassy mesostasis; bulk major-element composition similar to other nakhlites; element ratios confirm martian origin (FeO*/MnO = 37 mol/mol, Na/Al = 0.40, K/La = 449, Ga/Al = 3.9 × 10–4); has a higher proportion of mesostasis than other nakhlites; displays the highest Th, U and rare earth elements (REE) concentrations ever reported for a nakhlite (e.g., Th = 0.6 ppm); REE pattern characterized by a strong light REE enrichment (Lan/Ybn = 4.89), and Eu/Eu* =

0.90. Oxygen isotopes (M. Javoy and E. Petit, IPGP): ∆₁₇O = +0.4·. Specimens: 10 g, ENSL; main mass, Fectay.