Kuresoi        0°18.000’S, 35°31.735’E

Nakuru County, Kenya

Fell: 27 February 2014

Classification: Ordinary chondrite (L6)

History: Around 7:30 pm, on 27 February 2014, a bright fireball followed by sonic booms was observed by residents across several Rift Valley counties of Kenya. Most reports were from Bomet, Kericho, and Nakuru counties. The event was widely reported in local newspapers, such as the February 28 edition of Nairobi Exposed. A 555 g stone landed next to a house in Kuresoi, Nakuru County, and was immediately picked up. This stone was kept indoors, which accounts for its unweathered condition despite the rainy season from March to May. Paul Ara, from the neighboring town of Kericho, purchased the stone from the anonymous owners in Kuresoi, of which 279 g was subsequently acquired by Michael Farmer.

Physical characteristics: The exterior of the half stone is covered by dull, black fusion crust to 1 mm. Red clayey soil adheres to one side of the half stone. Interior is bright white, speckled with troilite, and crisscrossed by numerous thin shock veins.

Petrography: (L. Garvie, ASU) Chondrules difficult to recognize and largely integrated into the matrix. There are a few recognizable BO and RP chondrules. Plagioclase up to 100 μm is abundant. Chromite grains up to 200 μm are anhedral with rounded outlines. Troilite grains to 300 μm are largely single crystals and lack shock lamellae, except where cut by thin shock veins. Fe-Ni metal occur as two grain types: the first is irregularly shaped, up to 500 μm grains of kamacite that are equigranular and polycrystalline; the second is rounded grains up to 100 μm, with tetrataenite rims and cores of dark-etching plessite or acicular kamacite. Several of the latter grains have been cleanly cut and displaced by crosscutting shock veins. Metal grains lack Neumann bands. Native copper is rare: two small (10 μm) grains associated with troilite were found. Opaque, fine-grained melt pockets and veins are common.

Geochemistry: (L. Garvie, ASU) Olivine Fa_24.9±0.5, FeO/MnO=49.1±1.9, n=14. Ca-poor pyroxene Fs_21.2±1.1Wo_1.5±0.2, n=10. Ca-rich pyroxene, two analyses, Fs_7.0Wo_45.9 and Fs_8.0Wo_44.4. Feldspar An_10.3±0.2Or_5.1±0.2, n=4.

Classification: L6, W0. Low shock based on the lack of Neumann bands in the kamacite and shock lamellae in the troilite.

Specimens: 23.55 g and one polished mount at ASU. MFarmer and Paul Ara hold the rest of the material.