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www.niger-meteorite-recon.de
Bassikounou Meteorite Fall
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Maps & Appendix
By Svend Buhl & Matthias Baermann
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Geography and topography of the fall area
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Overlay of satellite data and topographic chart showing the Erg al Taha in the north
and the Oulimjan sandstone mesa butte in the north-east of Bassikounou
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About 1000 kilometres east by southeast of the capital
Nouakchott in the far south-eastern corner of Mauretania
lies the city of Bassikounou. Roughly 2000 inhabitants
populate the village which is a major junction in the traffic
across the near border to Mali, especially to the city of
Timbuktu. Bassikounou, or “Bassiknou” is inhabited mainly by
Fulbe, Soninké, Wolof and a small number of Bambara and
Touareg.
The ancient caravan route from the Atlantic coast
via Nema to Timbuktu passes through the city west to east.
Coming from the south is the piste from Nampala in Mali via
Koussana. Bassikounou has no airport and is only connected
by dust roads to the rest of the Mauritanian infrastructure.
The area is considered unsafe for western travellers.
Bassikounou is situated in a broad south-west north-east
oriented depression at the southern edge of the Erg Al
Tarha. The latter resembles the south-eastern tip of a
dry and mainly rock and sand covered chain of desert
plateaus (Dhar) bordered by cliffs towards the south east.
The Erg gently ascends over Dendara and Quatala to the Dhar
of Nema in the north- west. North and north-eastwards of
Bassikounou the terrain is mainly Erg and Hamada over 1000
kilometres before the mountainous
Adrar region begins in the borderland to Algeria.
About 15km east of the city the Bassikounou depression
is divided in two arms by the Oulimjam mesa-butte of continental
sandstone that stretches in north-easterly direction
across the border to Mali. The terrain opening in the
south towards Mali is a savannah like bush land with
little annual winter rainfalls.
The Erg surfaces beginning 10 kilometres north of
Bassikounou are mostly composed of fractured shales
of Mesozoic continental sandstone and Palaeozoic dolerite.
Sparse vegetation in the Bassikounou depression and the
advantageous topographic situation protecting against
wind erosion allowed a soil accumulation.
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The Oulimjam cutting into the
strewn field from the east. Several Bassikounou meteorites have been
found on the top of the plateau. In the
background there is a dense grow of Leptadenia pyrotechnica or "merekh" in Arab.
Photo courtesy of M. Zeroual
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Two main types of soil are abundant in the area.
A mineral rich laterite soil composed of fine and
coarser grained weathering products of the continental
sandstone, quartzite and dolerite. And second, a fine
grained chalky soil alternating with clay horizons. In some
areas within the strewn field, particularly in the south the
weathered red sandstone appears as surface bedrock.
Fireball and sound phenomena
During the cold and cloudless night at 04:00hrs
in the early morning of October 16, 2006 the people
in the Dhar Al Nema and the Hodh Ech Chargui regions were
alarmed by a bright and long lasting fireball that appeared
in the north-east. The phenomenon was visible at least up to 140
km north-east and 90 km south of Bassikounou.
The area in which
the descending fireball could be seen covers about 36,000 km2 of
mostly unpopulated desert. The limited number of eye witness
reports (17 in Bassikounou, 6 in the Dhar al Nema, 6 in other locations)
from the isolated area however includes a considerable
uncertainty factor in the direction and duration of the phaenomenon and in the area of
visibility.
Eyewitnesses from Bassikounou explained that three
burning spheres could be seen descending from the skies
with a breathtaking speed. The eyewittnesses from the Dhar al
Nema described one fireball as “bright as day”,
“enormous” and “too bright [to look at]”. All eye witnesses
are consistent in that the fireball(s) travelled with enormous
speed and lasted 30 -40 seconds. Some claimed that it lasted
“one minute”. In the last seconds of the phenomena the three fireballs
culminated in an “explosion of light” and sparks during which
“the night became as bright as day”. This final eruption of emitted
light lasted at least four or five seconds indicating that the
final brake up of the meteorite occurred successively.
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Distribution ellipse of the Bassikounou meteorite fall. Numbers indicate find
location of the El Moichine mass (1), several smaller masses of unknown
weight (2,3,4) and a 1304gm mass (5) found on the Djebel Oulimjam (catalog # 011)
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“A big star fell down at Bassikounou” Beille Mint Cheikh,
a 68 year-old resident of the Dhar al Nema region told
us when asked for what had happened in the night of
October 16. “It was a calm autumn night and many stars
were shining. Early in the morning all of a sudden one
became very bright. It travelled very fast towards the
direction of Bassikounou and brightened the sky for a long while.
The scene lasted for a minute; it was extremely abnormal,
unusual and indescribable.”
Apparently the fireball could also be seen from the
area 11 -19 km east of Bassikounou where the meteorite
fragments fell. Unfortunately no detailed description on the
light phenomena could be obtained from there. All witnesses in
the Bassikounou area and east reported “thunder” and “thunder
like sounds” accompanying the fireball. Because thunder in
Mauretania is always a sign of rain and the latter being
existentially important for the cattle and goat breeding
nomads everybody got up to see where the thunder
came from and where the rains may fall.
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Two eye witnesses; Mrs. Beille Mint Cheikh, 68, and Mrs. Mariem Mint
Yebbe. Photo Courtesy of Mohamed Yahya
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As no clouds could be seen and the noise grew abnormally
strong panic broke out in a number of villages and
particularly in the city of Bassikounou. Several
people told our correspondent Mohamed Yahya Ould Abdel
Wedoud that they were convinced “an earthquake" or "Doomsday" is coming.
“Some people were scared, puzzled and completely lost.
They did not know what was happening in the nature around
them and the old people told them that they had never
experienced anything similar falling from the skies.
Some began to pray to Allah", Mariem Mint Yebbe,
an eyewitness reported.
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Maps & Appendix
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