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Bassikounou
15°47'N, 5°54'W
Bassikounou, Hodh Ech Chargui, Mauritania
Fall: 16 October 2006; 04:00 UTC
Ordinary chondrite (H5)
History: A
fireball was witnessed in the area, but no records
of the direction of movement
were recorded.
A single stone of 3165 g was found by A. Salem El
Moichine, a local resident, on the same day at 13:00
hr local time, 11 km SE of Bassikounou. The sample
for classification was provided to NMBE by M. Ould
Mounir, Nouakchott, who obtained it from his cousin
who recovered the meteorite. According to S. Buhl
(Hamburg, Germany), more than 20 specimens were
later recovered by locals and meteorite finders.
These
finds define a 8 km long strewnfield. The total recovered
mass is 46.00 kg.
Physical characteristics: The 3165 g specimen is
largely covered by black fusion crust. The interior
is light gray. On the surface of the fusion crust
there is some adherent soil material, some of which
is bright red. Shortly after recovery, the stone
was cut into two pieces of 1200 and 1950 g. The larger
piece has a rectangular shape and shows indications
of flow-lines in the fusion crust.
Petrography: (E. Gnos, MHNGE; B. Hofmann, NMBE, M.
Eggimann, Bern/NMBE): Mean chondrule size 0.35 mm
(n=53). Metal abundance is 8 vol%, troilite 6.6 vol%.
Mean plagioclase grain size is ~20 mm. Troilite is
polycrystalline, rich in silicate inclusions, and
shows diffuse boundaries to metal. Metal is partly
rich in silicate- and troilite inclusions. Rare metallic
Cu (10 mm) occurs at kamacite-taenite boundaries
and in troilite. Some shock veins and no weathering
products were observed.
Mineral compositions: Olivine (Fa18.6), pyroxene
(Fs16.3 Wo1.1), plagioclase (An13.7).
Cosmogenic radionuclides: (P. Weber, PPGUN) Gamma-spectroscopy
performed in December-January 2006 showed the presence
of the following radionuclides: 48V, 46Sc, 56Co,
54Mn, 58Co, 7Be, 51Cr, 57Co, 22Na, 26Al and 60Co.
Recalculated to 12 October 2006 22Na was 38.0±2.2
and 26Al 31.5±2.1 (both dpm/kg), the activity
ratio of 1.21 is fully consistent with a fall on
that date.
Classification: Ordinary chondrite (H5); S2, W0.
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