New Raman Spectroscopic Data of the Almahata Sitta Meteorite

Abstract

ABSTRACT Raman spectroscopy is a convenient method to classify polytypes plus polymorphs and to investigate different compositions, structures, and modifications of minerals. This information is required to classify meteorites of different mineral compositions. Our intention was to examine different graphite modifications and to determine the opaque phases within the Almahatta Sitta (AS) meteorite. Our investigation focused on specimens AS39 and AS4. Both are multicomponent breccias, composed of different meteoritic lithologies, that is, anomalous polymict ureilite material, different types of chondrites, and an iron meteorite.[ 1-5 ] The mix of material implicates a crash of variable asteroids within time and space. This means that a primary ureilitic asteroid body has been the target of multiple meteorite or asteroid impacts, which did not completely destroy the asteroid but added new material (from chondritic to iron) to the main mass. For instance, Gabriel and Pack[ 6 ] suggested that the vein metal of monomict ureilites is introduced by the impact of a Ni-poor iron meteorite in a similar scenario as described above. Raman spectroscopy helped to investigate different carbon materials, that is, graphite and diamond. We used single-spectrum acquisition and spatial mappings to identify the different modifications. Furthermore, we classified minor opaque phases such as schreibersite, suessite, daubreelite, cohenite, and kamacite. The investigation of these opaque phases is dealt with in further papers.[1,2]