Al Haggounia 001

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 official classification.

The 255.9g Halved Individual below is part of the Meteorites Australia Collection (MA.10.0004).