Fine-grained rims in the Allan Hills 81002 and Lewis Cliff 90500 CM2 meteorites: Their origin and modification

Xin Hua, Jianhua Wang, P R Buseck

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

Antarctic CM meteorites Allan Hills (ALH) 81002 and Lewis Cliff (LEW) 90500 contain abundant fine-grained rims (FGRs) that surround a variety of coarse-grained objects. FGRs from both meteorites have similar compositions and petrographic features, independent of their enclosed objects. The FGRs are chemically homogeneous at the 10 μm scale for major and minor elements and at the 25 μm scale for trace elements. They display accretionary features and contain large amounts of volatiles, presumably water. They are depleted in Ca, Mn, and S but enriched in P. All FGRs show a slightly fractionated rare earth element (REE) pattern, with enrichments of Gd and Yb and depletion of Er. Gd is twice as abundant as Er. Our results indicate that those FGRs are not genetically related to their enclosed cores. They were sampled from a reservoir of homogeneously mixed dust, prior to accretion to their parent body. The rim materials subsequently experienced aqueous alteration under identical conditions. Based on their mineral, textural, and especially chemical similarities, we conclude that ALH 81002 and LEW 90500 likely have a similar or identical source.

Original languageEnglish (US)
Pages (from-to)229-244
Number of pages16
JournalMeteoritics and Planetary Science
Volume37
Issue number2
DOIs
StatePublished - Jan 1 2002

ASJC Scopus subject areas

  • Geophysics
  • Space and Planetary Science

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