Northwest Africa 2200

Morocco

Find: August 2004

Achondrite: (lunar, feldspathic breccia)

History: A completely crusted, 552 g, ellipsoidal stone was found in the Atlas Mountains, Morocco, and purchased in Erfoud by a Moroccan dealer for DGregory in August 2004.

Petrography and Geochemistry: (S. Kuehner and A. Irving, UWS) Breccia consisting of coarse, greyish-to-whitish lithic and mineral clasts in a darker glassy-to-finely crystalline matrix. Lithic clasts are mainly very fine-grained, quench-textured, feldspathic rocks that probably result from impact melting of anorthositic to gabbroic anorthositic precursors. A small percentage of the clasts are ophitic-textured mare basalts. Mineral clasts include anorthitic plagioclase, olivine (Fa_30–60), exsolved pigeonite, irregular grains of metal (Ni = 10–45 wt%), Ti-rich chromite, Ti-poor chromite, pyroxene-like glass, schreibersite (Ni = 5 wt%), clinopyroxene, ilmenite, troilite, and rare zirconolite. Clinopyroxene and orthopyroxene grains in mineral and lithic clasts have Fe/ (Fe+Mg) = 0.258–0.482 with Ti/(Ti+Cr) = 0.53–0.75. FeO/ MnO ratios measured for olivine (99.7, 105.5), clinopyroxene (73.7), and orthopyroxene (65.4) are unmistakably within the ranges for these minerals in known lunar rocks. Feldspar grains in mineral and lithic clasts have a narrow compositional range of An_95.8–97.4.

Classification: Achondrite (lunar, feldspathic breccia).

Specimens: A 20.5 g type specimen, one polished thin section, and one polished mount are on deposit at UWS. DGregory holds the main mass.