• Media type: E-Article
  • Title: Experimental partitioning of trace elements into schreibersite with applications to IIG iron meteorites
  • Contributor: Chabot, Nancy L.; Cueva, Rachel H.; Beck, Andrew W.; Ash, Richard D.
  • imprint: Wiley, 2020
  • Published in: Meteoritics & Planetary Science
  • Language: English
  • DOI: 10.1111/maps.13462
  • ISSN: 1945-5100; 1086-9379
  • Keywords: Space and Planetary Science ; Geophysics
  • Origination:
  • Footnote:
  • Description: <jats:title>Abstract</jats:title><jats:p>Some of the defining characteristics of the <jats:styled-content style="fixed-case">IIG</jats:styled-content> iron meteorite group are their high bulk P contents and massive, coarse schreibersite, which have been calculated to make up roughly 11–14 wt% of each specimen. In this study, we produced two data sets to investigate the formation of schreibersites in <jats:styled-content style="fixed-case">IIG</jats:styled-content> irons: measurements of trace elements in the <jats:styled-content style="fixed-case">IIG</jats:styled-content> iron meteorite Twannberg and experimental determinations of trace element partitioning into schreibersite. The schreibersite‐bearing experiments were conducted with schreibersite in equilibrium with a P‐rich melt and with bulk Ni contents ranging from 0 to 40 wt%. The partitioning behavior for the 20 elements measured in this study did not vary with Ni content. Comparison of the Twannberg measurements with the experimental results required a correction factor to account for the fact that the experiments were conducted in a simplified system that did not contain a solid metal phase. Previously determined solid metal/P‐rich melt partition coefficients were applied to infer schreibersite/solid metal partitioning behavior from the experiments, and once this correction was applied, the two data sets showed broad similarities between the schreibersite/solid metal distribution of elements. However, there were also differences noted, in particular between the Ni and P contents of the solid metal relative to the schreibersite inferred from the experiments compared to that measured in the Twannberg sample. These differences support previous interpretations that subsolidus schreibersite evolution has strongly influenced the Ni and P content now present in the solid metal phase of <jats:styled-content style="fixed-case">IIG</jats:styled-content> irons. Quantitative attempts to match the <jats:styled-content style="fixed-case">IIG</jats:styled-content> solid metal composition to that of late‐stage <jats:styled-content style="fixed-case">IIAB</jats:styled-content> irons through subsolidus schreibersite growth were not successful, but qualitatively, this study corroborates the striking similarities between the <jats:styled-content style="fixed-case">IIAB</jats:styled-content> and <jats:styled-content style="fixed-case">IIG</jats:styled-content> groups, which are highly suggestive of a possible genetic link between the groups as has been previously proposed.</jats:p>
  • Access State: Open Access