Northwest Africa 10602 (NWA 10602)

Mauritania

Purchased: April 2015

Classification: HED achondrite (Eucrite, melt breccia)

History: The sample was purchased by the main mass holder in Morocco, but is believed to originate in Mauritania.

Petrography: (R. Greenwood, OU) The meteorite is composed of angular, fine-grained, basaltic fragments up to 1 cm in diameter, enclosed in aphanitic, brown-stained, impact melt material. In a number of areas, oval vesicles up to 3 mm in long dimension are present in the impact melt material. The basaltic fragments have a generally uniform texture composed of acicular feldspar grains, generally less than 200 μm long, intergrown with dark, anhedral pyroxene grains. In places, a spherulitic texture is developed in the basaltic fragments, with elongate feldspars radiating outwards from a common point. Coarser-grained fragments with feldspar grains up to 0.5 mm long are also present. Feldspar in generally fresh, showing distinct undulose extinction in XPL. Pyroxene shows well-developed mosaicism.

Geochemistry: Mineral compositions and geochemistry: Pyroxene consists of a low-Ca pyroxene host, Fs_60.3±1.1Wo_3.7±1.3En_36.0±0.8 (±1σ, n=5), with well-developed exsolution lamellae of augite, Fs_27.3±1.1Wo_43.0±1.0En_29.7±0.5 (±1σ, n=4)). Plagioclase compositions are in the range An_85.9-91.4 (n=5). Oxygen isotopes: (Laser-assisted fluorination) δ¹⁷O = 2.349‰; δ¹⁸O = 4.952‰; Δ¹⁷O = -0.246‰ (Δ¹⁷O calculated using method of Miller (2002), GCA 66, 1881-1889).

Classification: This meteorite is a brecciated eucrite with a significant impact melt component. It shows low to moderate weathering. May be paired with NWA 10603. However, the texture observed in polished section is fairly distinct from that of NWA 10603.

Specimens: A type specimen mass of 20.95 g is held at the OU. The main mass is held by Mohammed Hmani.