Paposo 017        25°0’ S, 70°28’ W

Antofagasta, Chile

Found: 2010

Classification: Carbonaceous chondrite (CR2)

History: Found March 6, 2010, by Eric Christensen while searching for meteorites. Two pieces that fit together (238.6 g and 113.1 g) were found ~1 m apart.

Physical characteristics: Exterior with patches of frothy, bubbly flat-black fusion crust. Some cracks present. Sawn surface shows many large (to 3 mm though most 0.5 to 1 mm), well-defined chondrules (some stained red) in a fine-grained dark matrix. Sparsely distributed white calcium-aluminum-rich inclusions (to 1 mm) visible in a four cm2 slice. Metal weathered in patches; where present, is abundant in matrix and decorating chondrule rims. Stone moderately weathered.

Petrography: Thin section shows packed rounded to irregularly shaped chondrules separated by opaque matrix. Fine-grained sulfide and metal abundant in matrix. Metal ~60% weathered to iron oxides. Wide variety of chondrule types present including PO, POP, PP, RP, and BO, including many with igneous rims, for example, BO core with POP rim and large single-crystal olivine grain with POP rim. Low-Ca pyroxene with polysynthetic twinning common in some PP chondrules. Olivine shows planar fractures and undulatory extinction consistent with moderate shock.

Geochemistry: (P. Castleberry, D. Van Hoy and L. Garvie, ASU) Chondrule olivines show wide Fa range from Fa_0.5-55.5, n=38, with Cr₂O₃ to 1.1 wt%. Forsteritic olivines Fa_1.2±0.7, CaO=0.39±0.07 wt%, n=6. Low-Ca pyroxene has a wide Fs range from Fs_2.9-28.7, mean Fs_16.1±11.4Wo_1.3±1.3, Fe/Mn=19.7±7.8, Al₂O₃=0.4±0.3, n=18; pigeonite Fs_13.4Wo_15.3, n=1; augite Fs_15.4Wo_31.1, Cr₂O₃=1.6 wt%, n=1. Plagioclase Or_8.0Ab_12.9An_79.2, n=1.

Classification: Carbonaceous chondrite (CR2). Low microprobe totals from the matrix is consistent with type 2.

Specimens: 32.9 g and one polished thin section at ASU.