Catalina 037        25.1°S, 69.75833°W

Antofagasta, Chile

Found: 5 Jul 2010

Classification: Ureilite

History: On 5 July 2010, while hunting for meteorites, Eric Christensen found more than 100 fragments within several meters of each other totaling 2219 g, the largest of which was 654 g. Exteriors of the fragments are pitted. Fusion crust is lacking.

Physical characteristics: Stone relatively easy to cut with a diamond blade. Interior is brownish green. Polished slices (4 × 3 cm) show uneven distribution of fine- to medium-grained areas (dominant) and medium- to coarse-grained regions, with crystals to ~1 cm.

Petrography: (L. Garvie, ASU) Two thin sections examined. First section dominated by fine- to medium-grained (to 1.5 × 0.6 mm) anhedral grains of olivine and pigeonite, with slight preferred orientation, and abundant 120° triple junctions. Second section dominated by large pigeonite pyroxene grains poikilitically enclosing smaller, rounded compositionally homogenous olivines. Pigeonite and olivine have similar compositional ranges in the two sections. Very low reduction level with thin (<50 μm) reduction rims. Graphite flakes (to 150 × 50 μm) present between olivine grains. Very little metal and terrestrial oxides present. Fairly abundant olivine-olivine grain-boundary veins (to 60 μm wide) consisting of feldspar surrounding euhedral augite crystals (to 50 μm). Low-Ca pyroxene (<20 μm) occurs within the feldspar adjacent to the graphite-rich regions.

Geochemistry: (L. Garvie, ASU) Olivine cores Fa_19.9±0.3, FeO/MnO=45.6±3.4, CaO up to 0.34 wt%, Cr₂O₃ up to 0.51 wt%, n=14. Reduced rims down to Fa_3.4. Pigeonite Fs_16.6±0.2Wo_10.9±0.1, n=12. Olivine-olivine assemblage consisting of plagioclase feldspar host (two points analyzed An_47.6Ab_48.3Or_4.1, An_41.0Ab_48.7Or_10.3) enclosing euhedral low-Ca pyroxene (Fs_3.3±1.7Wo_5.0±0.5, n=3) and augite (Fs_2.1±0.7Wo_37.7±2.6, n=4).

Classification: Ureilite

Specimens: 83.5 g and two thin sections at ASU.