Northwest Africa 14912 (NWA 14912)

(Northwest Africa)

Purchased: Jan 2017

Classification: Ordinary chondrite (LL3-6)

History: Purchased from a Moroccan dealer by Mr. Jasper Spencer in 2017.

Physical characteristics: Physical Characteristics: CML received a single 35.4g slice; cut faces on either side of slice are medium to dark orange-brown with readily distinguished chondrules. A few (<5 area percent) light or dark colored clasts with a different texture than the host are visible.

Petrography: (M. Hutson, A. Ruzicka, Cascadia): Abundant partial chondrules, few complete chondrules, and numerous small angular chondrule fragments and individual grains appear crisply distinct against a dark background. In addition, two texturally different clasts (one light, one dark) are visible. The light clast is roughly triangular (~ 2.5 × 1.5 × 1 mm along edges) and coarse-grained, with chondrules barely discernible. The dark clast is oblate (~ 3.5 × 2.4 mm) and is difficult to see in plane-polarized transmitted light. In reflected light, numerous closely packed, deformed, and partial chondrules are surrounded by rims of weathered opaque material. A single complete and undeformed chondrule measures 0.95 mm in exposed diameter.

Geochemistry: Olivine in light triangular clast: Fa_29.8±0.2, N=5; Low-Ca pyroxene: Fs_23.9±0.6Wo_2.6±1.2, N=5. Olivine in dark oblate clast: Fa_19.0±10.4, N=11. Olivine (excluding two clasts): Fa_24.5±11.2, N=76; Low-Ca pyroxene (excluding two clasts): Fs_15.5±8.6Wo_1.0±0.8, N=46. While the Fa content of these 76 olivine grains ranges from 0.77 to 58.3, 41% (31 out of 76 grains) have Fa between 28 and 31, consistent with the chemistry of the light-colored clast.

Classification: Ordinary chondrite (LL3-6) based on mineral chemistry and texture. The light clast has texture and mineral chemistry consistent with LL6, but most of the section has texture and mineral chemistry consistent with LL3. The dark oblate clast has type 3 material and is heavily weathered.

Specimens: Cascadia holds 32.1 g in four pieces, as well as a polished thin section; Mr. Jasper Spencer holds the main mass.