Metal-silicate-sulphide segregation within the Yaringie Hill meteorite
thesisposted on 2022-03-28, 20:38 authored by Harry West
The study of the Yaringie Hill meteorite offers a unique opportunity to investigate the early stages of the planetary building cycle, in particular, the mechanisms controlling core formation. This H5 ordinary chondrite features a crosscutting metal vein that has allowed investigation of metal-silicate-sulphide segregation mechanisms on the ordinary chondrite parent body. This study focused on trace element analysis of metals and sulphides using LA-ICP-MS and the establishment of textural relationships through optical and SEM analysis. The vein metal is depleted in HSE relative to matrix metal, and appears to be the result of injection rather than local partial melting. Comparative study against terrestrial and meteoric segregation mechanisms concludes the vein neither formed via shock metamorphism as previously interpreted, or a smelting process. The vein instead appears to be derived from vapour deposition resulting from impact vapourisation. HSE patterns and abundances relative to iron meteorites highlight the vein being transitional toward the IIIAB irons and pallasites, indicating processes like vapour deposition may contribute to final core composition. Further research in this area should focus on building a larger body of research around the mechanism of vapour deposition and its impact on planetary core formation.