Frontier Mountain 93001

Antarctica

Found 1994 January 4

Primitive achondrite (Acapulcoite-Lodranite)

This 4.84 g small stone is a ~16 x 13 x 12 mm, angular, 20% fusion crusted fragment found by a PNRA/EUROMET team. Mineralogy and classification (A. Burroni and L. Folco): FRO 93001 is a medium- to coarse-grained, gabbroic rock consisting of (in order of abundance) orthoenstatite (Fs_13.3±0.4 Wo_3.1±0.2), oligoclase (Ab_80.5±3.3 Or_3.2±0.6), augite (Fs_6.1±0.7 Wo_42.3±0.9) and traces of olivine (Fa_13.3±0.3; [Mn/Mg] = 0.006). Corroded xenoliths of probable lodranitic composition float in the gabbroic host lithology; they mainly include granoblastic olivine Fo_90.4±0.7 with average grain size of 400 μm, lesser Fe,Ni metal, and minor chromite (Cr/(Cr+Al) = 0.84; Fe/(Fe+Mg) = 0.64), phosphates, schreibersite, and troilite. The rock (including xenoliths) is devoid of shock features (shock stage S1) and nearly unweathered (weathering degree, W1). FRO 93001 is similar to the igneous lithology, that intrudes an acapulcoite host in the Lewis Cliff (LEW) 86220 meteorite described by McCoy et al. (1997). Specimens: main mass, 2.57 g, two thin sections, MNA-SI; one thin section, NHM, type specimen, 1.60 g, OU.