Northwest Africa 14789 (NWA 14789)

Morocco

Purchased: 2012

Classification: Ordinary chondrite (LL5)

History: Sample was purchased in 2012 from Adam Aaronson at the Tucson mineral show who acquired it from Morocco. Sample is catalogued at ROM as M58211.

Physical characteristics: Fist-sized individual with smoothly curved fusion crust on 40% of surface, a regmalypted fusion crust surface (20%) and broken surfaces (40%). All surfaces show mature desert polish. Tan-weathered broken surfaces show mm-sized chondrules and chondrule sockets. Physical properties: Magnetic susceptibility measured for a 6.49 g sample is log χ (× 10^-9 m³/kg) = 3.57.

Petrography: Cut faces totalling 13 cm2 show a grey-green chondrule-bearing brecciated rock laced with irregular dark veins and patches. The chondrite contains finely disseminated metal grains and some >mm metal and sulfide composite grains. The polished thin section consists of chondritic rock cut extensively by dark fragmental groundmass veins, which contain angular irregular clasts of the host chondrite. Vein contacts are sharp. The host chondrite shows extensive fracture development, containing poorly delineated chondrules and chondrule fragments. Olivine and pyroxene grains show planar fractures and undulatory to mosaic extinction. Fe oxide staining of silicates is limited to haloes surrounding iron-sulfide composite grains and reddening of the dark groundmass material. In BSE images, groundmass vein material contains abundant very fine μm grains of metal and sulfide.

Geochemistry: EPMA: Olivine Fa_30.20±0.61 (n=30); Ca-poor pyroxene Fs_24.34±1.66Wo_2.63±1.07 (n=22); Ca-rich pyroxene Wo_40.86±2.31Fs_11.90±1.40 (n=7).

Classification: Ordinary chondrite: LL5 (S4) W1. EPMA olivine and pyroxene Fe rich compositions and low magnetic susceptibility indicate LL chondrite. The meteorite has an extensive shock vein network of dark, fragmental groundmass material.

Specimens: Type specimen location: ROM. Main mass: DGregory.