Si-Mg isotopes in enstatite chondrites and accretion of reduced planetary bodies.

ABSTRACT: Among the primitive meteorite classes, Enstatite Chondrites (EC) are believed to share a common origin with the Earth due to its close similarity with terrestrial mantle (Bulk Silicate Earth, BSE) for numerous isotope systematics. Si isotopes are an exception to this trend and the large δ³⁰Si difference of ~0.3‰ between bulk EC and BSE has been used to argue against any major contribution of EC like planetary materials in Earth's accretion. However, Si possess a bimodal distribution among silicate and metallic fractions of EC because of its formation under highly reducing conditions. Based on high precision Si isotope analyses in micro-milled phase separates of EH3 chondrites, here we report the presence of significantly light Si isotopes in EC-metals (δ³⁰Si ≥ -6.94 ±

SUBMITTER: Sikdar J 

PROVIDER: S-EPMC6985146 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature