Northwest Africa 8576 (NWA 8576)

Morocco

Purchased: May 2014

Classification: Ordinary chondrite (LL3.00)

History: Purchased by Brahim Tahiri from a Moroccan hunter in Erfoud, Morocco and sent to his partner Sean Tutorow for classification.

Geochemistry: Ferroan olivine contains 0.46±0.09 wt.% Cr₂O₃, n=25; Kamacite: 0.42±0.26 wt.% Co; 5.5±1.8 wt.% Ni (n=9). There is a positive correlation between the Co and Ni values in the kamacite, as is found in other highly unequilibrated chondrites. The Cr content of the kamacite is 0.22±0.31 wt.% with a range of 0.00-0.84 wt.%. P (0.03±0.03 wt.%) and Si (0.03±0.04 wt.%) are both approximately at the detection limit.

Classification: Optical microscopy shows that this meteorite has ferroan olivine grains with no chromite exsolution; this implies it is outside the 3.05-3.15 range. About 10 different porphyritic chondrules in the thin section were examined. The meteorite cannot be type 3.2 or higher since it has such high Cr in the ferroan olivine and a low standard deviation similar to Semarkona (LL3.00), Grossman and Brearley (2005). The chondrules average about 600 μm in diameter, consistent with an LL classification.