NORTHWEST AFRICA 7030


Meta-LL

standby for nwa 7030 photo
click on photo for a magnified view

Found 2011
no coordinates recorded

A single fusion crusted stone weighing 224 g was found in Northwest Africa and subsequently sold to meteorite dealer G. Hupé in Zagora, Morocco. A sample was submitted for analysis and classification to the University of Washington in Seattle (A. Irving and S. Kuehner), and NWA 7030 was determined to be a metachondrite with similarities to the LL chondrite group.

Northwest Africa 7030 is a texturally evolved meteorite that lacks any relict chondrules, and it exhibits an overall texture akin to a fine-grained igneous cumulate. The predominant lithology was described as consisting of olivine, clinopyroxene, sodic plagioclase, chromite, troilite and taenite. A less prevalent greenish-colored, igneous-textured lithology is also present. Its composition is different from that of the primary lithology in that it contains interstitial potassic-feldspar (sanidine) along with albitic plagioclase, and it contains much less troilite. Another difference is the presence of orthopyroxene and rare kamacite in the minor lithology (Fernandes et al., 2014).

The O-isotopic composition of NWA 7030 was analyzed at Okayama University (R. Tanaka) and it was shown to plot within the LL chondrite field. Bulk density measurements for NWA 7030 were conducted at the University of Central Florida (D. Britt [UCF]; B. Macke and G. Consolmagno [Vatican]) employing both pycnometer and glass bead methods (results forthcoming).

Although NWA 7030 was shown to have affinities to the LL-chondrite group, it has many anomalous features that make it unique, and therefore, could be considered as ungrouped. The K–Ar age was determined for the minor lithology, and the results indicate the occurrence of two separate impact heating/degassing events that have disturbed this isotopic chronometer: one at ~4.12 b.y. and the other at ~2.39 b.y. (Fernandes et al., 2014).

The specimen of NWA 7030 shown above is a 0.77 g end section. The top photo below shows the fresh fusion-crusted mass, while the bottom photo shows the interior of a 15.62 g slice with both lithologies—photos courtesy of Greg Hupé.




Photos courtesy of Greg Hupé—Nature's Vault