Northwest Africa 2700

Morocco

Find: 2004

Achondrite (lunar, olivine gabbro with regolith breccia)

History: A light green to dark complete stone of 31.7 g was purchased in Erfoud, Morocco, in November 2004.

Petrography and Geochemistry: (T. Bunch and J. Wittke, NAU) The specimen consists of olivine gabbro and regolith breccia lithologies. The cumulate olivine gabbro contains ~50 vol% olivine (Fa_29.3–34.7; FeO/MnO = 94), pigeonite (Fs_22–28.3Wo_5.6–10; FeO/MnO = 52), augite (Fs_13.2Wo_38.5), plagioclase and minor maskelynite (An₈₉), Ba-rich alkali feldspar (Or₉₂An₄; BaO = 8.9 wt%), Cr-spinel, ilmenite, phosphate, and troilite. The breccia lithology is dominated by small olivine gabbro fragments and also contains subvariolitic basalt clasts with zoned pyroxenes (Fs₄₄Wo₂₉ to Fs₅₈Wo₂₃; FeO/MnO = 57); plagioclase (An₉₀); ilmenite, and Fe-rich, low-Ca pyroxene (Fs_80.8Wo₁₄); symplectites of fayalite (Fa₉₁); hedenbergite (Fs_60.3Wo_32.7); silica; clear to yellow glass spherules; agglutinates, high silica fayalitic rocks (Fa_95.6); ulvöspinel; K₂O -rich glass (K₂O = 8.8; SiO₂ = 77 [both wt%]), and pure SiO₂.

Classification: Achondrite (lunar, olivine gabbro with regolith breccia) where the olivine gabbro is moderately shocked and minimally weathered. Note: This sample may be paired with NWA 773.

Specimens: A 6.8 g type specimen and two thin sections are on deposit at NAU. An anonymous finder holds the main mass.