Meteorite Jesenice: Mineral and chemical composition of the fusion crust of ordinary chondrite

Abstract

The composition of the well-preserved fusion crust of the meteorite Jesenice was characterised by means of optical and scanning electron microscopy (SEM). The SEM investigations revealed three structurally distinct layers within the crust. The features of the first layer on the surface are precipitates, enriched in metal elements (iron, nickel), and the partial melting of silicate grains, which continues deeper into the second layer. The second layer beneath has veins with a heterogeneous composition that indicates a different source of melting minerals. The third layer, which is located deeper within the fusion crust, has not undergone any structural changes and its features are similar to the interior of the meteorite. This is additionally confirmed by the presence of cracks, which are a consequence of shock metamorphism, and irregularly shaped metal and sulphide grains. The structural changes of the thin fusion crust on the surface of this stony meteorite indicate high temperatures (more than 1500 °C) accompanied by high pressures.