Los Vientos 001        24°42.000’S, 69°45.000’W

Antofagasta, Chile

Found: 29 Dec 2009

Classification: HED achondrite (Diogenite, polymict)

Physical characteristics: One stone was found with a total weight of 73 g. Dull, moderately weathered black fusion crust covers ~80% of the stone. The interior of the stone is grey with minor iron-oxide staining.

Petrography: (Laurence Garvie, ASU) Orthopyroxene-rich breccia with clasts (<1 to 5 mm) and mineral fragments with a range of textures and compositions, supported by fine-grained orthopyroxene matrix. The majority of the clasts (~90%) rounded to angular, unzoned low Ca-pyroxene (Fs_24.1-33.4Wo_2.0-3.0), and large (mm-sized) opaque-rich (FeS and chromite) low Ca-pyroxene (Fs_20.1-26.5Wo_0.4-2.4). Plagioclase clasts (An_84.5-93.9Or_0.2-0.5) abundant. Thin section contains a range of clast types, with a diversity of lithologies some with cumulate eucrite texture and compositions and other unique clasts: mm-sized, divergent plagioclase (An_70.7-72.2Or_1.1-1.3) with interstitial Fs_14.8Wo_41.9 and silica grains; mm-sized clast of Fs_38.2Wo_2.9 and An_93.8Or_0.1; zoned low Ca-pyroxene with Fs_22.8Wo_2.44 at center and Fs_30.4Wo_2.6 at grain edge; large (mm-sized) pyroxene with complex zoning, Fs_38.6Wo_2.7 with lamellae of Fs_19.8Wo_40.5, grain center is Fs_46.9Wo_2.1, also contains chadacrysts of An_85.4Or_0.3; 100 μm clast of An_84.5Or_0.5 with 10 μm chadacrysts of Fs_12.0Wo_44.4; large (mm) Fs_43.3Wo_7.0 grain with lamellae of Fs_36.2Wo_19.7; and large (mm) Fs_36.2Wo_3.6 grain with lamellae of Fs_20.0Wo_40.1. Silica and chromite (to 1 mm) scattered throughout the section. Also sparse kamacite and Ti-spinel.

Classification: Achondrite (diogenite, polymict breccia); Shock level is moderate, with variable shock levels in clasts. Minimal weathering. Visually, the stone looks like a howardite with dark clasts similar to NWA 776. However, the predominance of unzoned low-Ca pyroxene is more consistent with diogenites and the diversity of lithologies warrant the polymict designation.

Specimens: Type specimen, 73 g, ASU; main mass, E. Christensen