Description
One of the 8 meteorites classified as achondrite primitive ungrouped.
Writeup from MB 113:
NWA 15061, reclassification
This meteorite is reclassified (K. Metzler, IfP) as an ungrouped primitive achondrite, likely paired with Bir Ounane 001. Oxygen isotopes, obtained by laser fluorination (T. Di Rocco, UGött) are: δ18O= 5.710; δ17O= 1.709; Δ17O= -1.298 (permil). The two meteorites have similar textures and mineral compositions (Fa~1.2, Fs~1.4Wo~0.8).
Writeup from MB 111:
Northwest Africa 15061 (NWA 15061)
Mali
Purchased: 2022 Mar
Classification: Primitive achondrite (Winonaite)
History: Reportedly found by Saharawi meteorite hunters in an area called Unan (~120 km SE of Taoudenni), Mali, in February 2022.
Petrography: (K. Metzler, IfP) Achondrite with metamorphic texture, showing frequent 120° triple junctions and partly poikilitic intergrowths. It consists of olivine, low-Ca pyroxene, Ca-rich pyroxene, plagioclase, and Fe-Ni metal. Much of the latter is terrestrially oxidized, forming veins of alteration products along grain boundaries and crosscutting mineral grains. Typical grain sizes are between 200 and 500 µm, but low-Ca pyroxene grains up to several mm occur. Accessories are troilite and daubréelite.
Geochemistry: Mineral compositions and geochemistry: The mean olivine composition is Fa1.2±0.1 (Fa1.0-1.4; n=9). The mean low-Ca pyroxene composition is Fs1.4±0.3Wo0.8±0.1 (Fs0.9-1.8Wo0.5-0.9; n=11). The mean composition of Ca-rich pyroxene is Fs0.9±0.3Wo40.9±0.5 (Fs0.5-1.4Wo40.3-41.6; n=10). The mean feldspar composition is An36.5±2.0Or0.1±0.1 (An32.1-38.6Or0.0-0.4; n=10).
Classification: Winonaite, based on texture, mineral chemistry and high abundance of Fe-Ni metal.
Specimens: 3292 g owned by Mohamed Ali Loud (largest piece 385 g). 2430 g owned by Miguel Ángel Contreras Gómez.
