Yucca 049        34°49.033’N, 114°16.238’W

Arizona, United States

Find: 01 May 2014

Classification: Ordinary chondrite (H3-5)

History: Found by Troy Ball on May 1, 2013. The entire stone was donated to Cascadia in September, 2013.

Physical characteristics: Stone entirely coated with weathered fusion crust, which varies in color from dark brown to reddish brown. Two small (<1 cm across) patches of crust are missing, revealing a lighter colored reddish-stained interior.

Petrography: In thin section, the sample appears to be relatively integrated, with many chondrule fragments and only a few complete chondrules present; distinct lithic clasts typical of a breccia are absent. The material between chondrule fragments is comprised of individual grains and smaller fragments. BSE imaging shows that most of meteorite consists of fragmental material, with an abundance of magnesian and iron-rich olivine and pyroxene grains, many of which show zoning, and which abut equilibrated fragments with typical H-chondrite compositions. Notable petrographic features include a fragment with zoned Fe-rich low-Ca pyroxene and coarse (up to 80 µm across) equant silica polymorph with veins and a partial rim of olivine; a large (~750 µm across) chromite-plagioclase region that encloses olivine; and an irregular fragment (~200 µm across) that contains elongate chromite-plagioclase pseudomorphs and Ca-pyroxene set in plagioclase. Coarse merrillite (up to 200 µm across) and Fe-Ni carbide was observed

Geochemistry: (M. Hutson and A. Ruzicka, Cascadia) Sample contains a wide range of compositions of olivine (Fa_19.5±5.1, N=71), low-Ca pyroxene (Fs_15.6±6.4Wo_1.2±1.1, N= 44). The pyroxene-silica fragment has zoned Fe-rich low-Ca pyroxene (Fs _33.5±6.3Wo_1.8±0.3, N=7); the surrounding shell and vein olivine are somewhat higher in iron (Fs_26.9±5.3, N=19) than the host olivine.

Classification: Although the chemistry and abundance of zoned grains suggests a type 3 designation, the presence of medium-sized crystalline feldspar, coarse phosphate, and chromite-plagioclase objects suggests a higher petrographic type. The thin section studied strongly resembles the "main" lithology found in the Buck Mountain Wash chondrite, suggesting that this is an H3-5 finely intermixed genomict breccia. Paired with Buck Mountain Wash (synonymous with Yucca 002) on the basis of mineralogy, mineral chemistry, and texture.

Specimens: Cascadia holds the entire type specimen and main mass, which consists of 18.4 g in two pieces, in addition to a polished thin section and a mounted butt