Mass fractionation of nickel isotopes in metallic cosmic spheres

The isotopic abundances of stable Ni isotopes were measured by inductively coupled plasma mass spectrometry (ICP/MS) in seven cosmic, metallic (Type I) spheres collected from the deep sea. Mass-dependent enrichments of the heavier isotopes range from 0.5–2.8% / AMU, values larger than those reported previously for Ni in any solid, extraterrestrial sample. This mass fractionation most likely reflects the high-temperature vaporization and loss from some spheres of over 90% of the Ni initially present.