Northwest Africa 14483 (NWA 14483)

(Northwest Africa)

Purchased: 2017

Classification: HED achondrite (Eucrite, melt breccia)

History: Purchased by Ken Regelman in 2017 from a Mococcan dealer.

Petrography: (A. Irving, UWS and J. Boesenberg, BrownU) Complex breccia composed predominantly of closely packed microgabbroic eucrite clasts and related crystalline debris, plus <10 vol.% diogenitic orthopyroxene, together with very sparse, patchily distributed, ultrafine grained melt matrix (dark gray to opaque in thin section). Eucritic clasts and debris contain calcic plagioclase (some polycrystalline), exsolved pigeonite (some polycrystalline, some partly altered to red-brown Fe oxides), silica polymorph, chromite, troilite and Fe metal. Several grains of olivine with intermediate Fa contents (unlike those typically found in either diogenites or eucrites) and some patches of secondary calcite are present.

Geochemistry: Diogenitic orthopyroxene (Fs_29.4-36.8Wo_2.1-3.2, FeO/MnO = 26-34, N = 6), low-Ca pyroxene hosts (Fs_58.5-62.3Wo_3.1-1.9, FeO/MnO = 30-32, N = 2), augite exsolution lamellae (Fs_26.3-29.0Wo_41.6-41.2, FeO/MnO = 30-31, N = 2), pigeonite (Fs_37.9-43.7Wo_10.2-8.7, FeO/MnO = 27-32, N = 4), low-Ca pyroxene (Fs_41.4-46.7Wo_1.0-4.3, FeO/MnO = 25-33, N = 3), subcalcic augite (Fs_27.8Wo_28.6), olivine (Fa_56.7-57.4, FeO/MnO = 47-49, N = 3), plagioclase (An_80.8-95.6Or_1.7-0.1, N = 7).

Classification: Eucrite (polymict melt breccia, shocked).

Specimens: 20.7 g including one polished thin section at UWB; remainder with Mr. K. Regelman.