Al Haggounia 001 was first discovered in late
2005 under a saline playa located 30km east of El Haggounia,
Western Sahara. Two batches of stones were initially classified by two
different institutions during 2006. One classified the
meteorite as a rare Aubrite which stands as the current official
classification and the other as an EL6/7 chondrite.
At least 3 tonnes of material has since been recovered since
2005 from an
ancient strewnfield which extends some 40kms in length. Stones
have been found on the surface but have also been recovered from
a buried depth of almost 1 metre.
This meteorite has been the centre of much
debate over the last few years with different institutions
classifying it as different things. In fact this meteorite is
classified under at least a couple of dozen NWA numbers with
various Aubrite and Enstatite Chondrite classes represented. The
problem lies in the fact that the meteorite can vary widely from
one specimen to the next which is primarily due to weathering
effects. Al Haggounia has actually been termed a "fossil" or "paleo"
meteorite with a terrestrial age of 23,000 ±2000 years being
determined. The less weathered parts of the meteorite appear as
a bluish-grey colour which is usually seen in the interior of
stones while the more weathered stones/sections appear brown and
sometimes very fractured.
The two initial classifications were derived
from specimens/type-samples that were a very limited representation
of the overall material. Well-formed chondrules are indeed
present in this meteorite however they are extremely sparse.
This coupled with the fact that many specimens were extremely
altered by terrestrial weathering processes led to the initial
classifications. Another study showed that the elemental
abundances fit the E-Chondrites except for the Iron, Nickel and
Cobalt levels which are extremely depleted. However this can be
simply explained by the terrestrial processes which weathered
these metals out over time.
Two of the original classifying scientists have
conducted an extensive and methodical study
of many different samples of Al Haggounia and concluded that the best description
for this meteorite is an Anomalous EL3 Chondrite (W4). The
revising scientists have rightfully stated that "the designation
as Type 3 is appropriate, given the presence of glass in
chondrules and the well-preserved chondrule shapes (note that
abundance of chondrules is not a criterion)." However even with
Type 3 chondrules now being carefully studied and reported in Al Haggounia
specimens (which precludes an Aubrite classification) and the
Meteoritical Bulletin officially pairing them with Enstatite
Chondrite NWA's; the Meteoritical Society has yet to alter the
The 255.9g Halved Individual below
is part of the Meteorites Australia Collection (MA.10.0004).