Northwest Africa 4423
Morocco
Find
Carbonaceous chondrite (CK3)
History: A stone, said to have been found near Hammada
du Guir, Morocco, was purchased by P. Thomas in May 2006
Physical characteristics: One stone, weighing 91.94 g,
entirely covered with a very black fusion crust.
Petrography: (M. Bourot-Denise, MNHNP) Chondrules and CAIs
are clearly visible to the naked eye and are mm-sized;
CAIs are particularly abundant. Magnetite, the most abundant
opaque mineral, makes large nodules around chondrules or,
in association with sulfides (mostly pyrrhotite), in the
matrix; it is also found as smaller grains rimming chondrules,
AOAs and CAIs, and in chondrule rims; very small flecks
of magnetite are located in a few areas of finer matrix.
In BSE images, the chondrite appears not to be completely
equilibrated, with zoned olivines and low-Ca pyroxenes
in POP chondrules. Outside chondrules, high-Ca pyroxene
is augite and diopside. The studied polished section features
a large CAI, 3000 µm in size, rimmed with small magnetites.
Geochemistry: Olivine (mean Fa = 16.4 ± 12.7, range
0.31-32.7), Low-Ca pyroxene (Fs = 7.9 ± 8.6, range
1.1-24.1; magnetite (Cr2O3 = 2.35, MgO = 0.84 [both in
wt%]), plagioclase (An22.6-77.6). Magnetic susceptibility:
(J. Gattacceca, CEREGE) = log c = 4.7 10-9 m3/kg.
Classification: Carbonaceous chondrite (CK3, estimated
subtype 3.8); minimal shock and moderate weathering.
Type specimens: A total of 19.1 g of sample (4 sawn fragments)
and one polished mount is on deposit at MNHNP. Thomas holds
the main mass.
Sorry!
this meteorite is no more available for sale.
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