Highly concentrated nebular noble gases in porous nanocarbon separates from the Saratov (L4) meteorite

Sachiko Amari, Jun Ichi Matsuda, Rhonda M. Stroud, Matthew F. Chisholm

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

The majority of heavy noble gases (Ar, Kr, and Xe) in primitive meteorites are stored in a poorly understood phase called Q. Although Q is thought to be carbonaceous, the full identity of the phase has remained elusive for almost four decades. In order to better characterize phase Q and, in turn, the early solar nebula, we separated carbon-rich fractions from the Saratov (L4) meteorite. We chose this meteorite because Q is most resistant in thermal alteration among carbonaceous noble gas carriers in meteorites and we hoped that, in this highly metamorphosed meteorite, Q would be present but not diamond: these two phases are very difficult to separate from each other. One of the fractions, AJ, has the highest 132Xe concentration of 2.1 × 10-6 cm3 STP g-1, exceeding any Q-rich fractions that have yet been analyzed. Transmission electron microscopy studies of the fraction AJ and a less Q-rich fraction AI indicate that they both are primarily porous carbon that consists of domains with short-range graphene orders, with variable packing in three dimensions, but no long-range graphitic order. The relative abundance of Xe and C atoms (6:109) in the separates indicates that individual noble gas atoms are associated with only a minor component of the porous carbon, possibly one or more specific arrangements of the nanoparticulate graphene.

Original languageEnglish
Article number37
JournalAstrophysical Journal
Volume778
Issue number1
DOIs
StatePublished - Nov 20 2013

Keywords

  • meteorites
  • meteoroids
  • meteors

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