Meteoryty Bez Ściemy 44 - EUKRYT 2 скачать в хорошем качестве

Meteoryty Bez Ściemy 44 - EUKRYT 2

Klasyfikacja tego eukrytu Northwest Africa 15923 (NWA 15923) Classification: HED achondrite (Eucrite, melt breccia) History: Mark Lyon purchased 105 kg of similar looking fusion crusted achondritic meteorites from a meteorite dealer in Mauritania in 2022/2023. The largest stone is 12 kg. A 433.7 g stone was donated to the Buseck Center for Meteorite Studies at ASU. Physical characteristics: A fresh, fusion crusted angular stone with poorly developed regmaglypts. Fusion crust is locally glossy with well developed flow patterns. Sawn surface (7 × 5 cm) shows coarse breccia of light-colored rounded breccia clasts separated by dark vesicular melt veins with a matte-black appearance. Clasts are poorly sorted and range considerably in size, many measuring several centimeters. Petrography: (E. Mares, S. Ravikumar, L. Garvie, A. Wittmann, ASU) Eucrite-melt breccia with clasts to 5 cm with a distinct boundary to the black melt veins. Predominant minerals are up to 1-mm-sized exsolved pyroxenes and calcic plagioclase that exhibit gabbroic cumulate textures. All clasts appear similar in their modal mineralogies, suggesting the sample is a monomict breccia. Accessory phases include ilmenite, chromite, troilite, silica, F-rich Ca phosphate, Ca-Fe-Mg phosphate, and zircon. Small grains of ilmenite and chromite are present as inclusions within the pyroxene-plagioclase clasts. Troilite is primarily encountered as small rounded blebs within the melt veins. No metallic Fe-Ni detected.