THE METEORITICAL BULLETIN
Announcement 85-4, April 4, 2001
Jeffrey N. Grossman, Editor (jgrossman@usgs.gov)
Jutta Zipfel, Co-editor for Saharan Meteorites
(zipfel@mpch-mainz.mpg.de)
The following text of announcements will be published in
Meteoritical Bulletin, No. 85, 2001 July.
Northwest Africa 480 Martian meteorite found in Morocco (?)
Northwest Africa 482 Lunar meteorite found in Morocco (?)
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Northwest Africa 480
Northwest Africa
Found 2000 November
Martian meteorite (basaltic shergottite)
A 28 g stone almost completely covered with fusion crust was found in
Morocco. Classification and mineralogy (J.-A. Barrat, UAng, A.
Jambon, UPVI, Violaine Sautter, MNHNP, Ph. Gillet, ENSL): the
meteorite has a coarse-grained basaltic texture consisting
predominately of subhedral to euhedral pyroxene (up to 3 mm) and
interstitial, lath-shaped maskelynite; accessory minerals include
merrilite, chlorapatite, pyrrhotite, Fe-oxides, fayalite and silica;
pyroxenes show complex zonation with Mg-rich pigeonite cores (Fs26
Wo4), followed by augite (Fs29 Wo30), and mantled by Fe-rich
pigeonite (Fs84 Wo11); no pyroxferroite has been detected;
maskelynites homogeneous, An46-50 Ab52-48 Or~2; merrilite forms
rounded grains (up to 100 um) and is Fe-rich (~5 wt. % FeO),
commonly with 6-40 um thick rims of fayalite (Fa~95), silica, Fe-Ti
oxides, and pyrrhotite; silica (stishovite) occurs as irregular
grains in maskelynite or at grain boundaries to pyroxene and is
surrounded by radiating cracks. Oxygen isotopes (M. Javoy and E.
Petit, IPGP): d18O = +4.78 permil, d17O = +2.91 permil and D17O =
+0.42. Specimens: main mass, 25 g, CNES.
Northwest Africa 482
Northwest Africa
Found 2000?
Lunar meteorite (impact melt breccia)
A 1015 g stone was purchased on 2001 January 10 in Alnif, Morocco, by
Michael Farmer. The exact location of find is unknown but it is
possibly in Algeria. The stone is complete, oriented, and appears
relatively unweathered. Classification and mineralogy (A. Rubin and
P. Warren, UCLA, and D. Kring and I. Daubar, UAz): texture is typical
of a crystalline impact melt breccia (polymict) with highland
affinities; glassy and vesicular melt veins and melt pockets indicate
shock subsequent to compaction by an impact event; plagioclase,
An95.7 Ab4.09 Or0.17 (n = 136, UAz); olivine, Fo65-68 (average Fo66)
with FeO/MnO = 88 +/- 7 g/g (UCLA); olivine Fo68.4 with FeO/MnO =
93.9 +/- 7.7 g/g (range: 78.7 to 111) (n = 51, UAz); pyroxene, Fs25
Wo17 with nearly uniform Mg/(Mg+Fe) = 67 ñ 68 mol% and FeO/MnO = 51
+/- 6 g/g (n = 10, UCLA); pyroxene, Wo10.3-51 En32.6-63.9 Fs42.6-
14.2, mean Mg/(Mg+Fe) = 68 mol%, FeO/MnO = 52 +/- 8 g/g (n = 28,
UAz); glassy melt veins occur in both UCLA and UAz samples; a 0.1 mm
vein (UCLA) has SiO2 = 44.3 wt.%, Na2O = 0.3 wt.%, Al2O3 = 30.0
wt.%, FeO = 3.6 wr.%, MgO = 3.9 wt.%, CaO = 17.3 wt.%, and TiO2 = 0.3
wt.%, which may approximate the bulk meteorite composition.
Specimens: half of the main mass is with Farmer; type specimens, 24
g, UCLA, and 18 g, UAz.
