NORTHWEST AFRICA 974

A single highly-weathered stone weighing 2,250 g was found by villagers near Remlia, Morocco, in April 2001. Northwest Africa 974 is composed primarily of enstatite and kamacite, along with minor plagioclase, oldahmite, daubreelite, alabandite, schreibersite, troilite, graphite and silica. It is moderately shocked to stage S4.

Despite its high content of kamacite, consistent with an EH classification, other compositional characteristics are more consistent with an EL classification. For example, the presence of alabandite rather than niningerite is typically diagnostic of the EL group, as is the relatively high content of anorthite present in NWA 974. The classifying investigator (A. Jambon, Université Pierre & Marie Curie) believes that these represent anomalous characteristics attributable to the high metamorphism which the stone has experienced, and he has suggested a classification of EH6 as the most appropriate for this stone. Further studies should help resolve the ambiguity in the classification of this enstatite chondrite.

On May 8, 2008 the classification of NWA 974 was revised by the Nomenclature Committee of the Meteoritical Society to reflect a recommendation of E6 chondrite, pending further analyses. The specimen of NWA 974 shown above is a 2.89 g partial slice.

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