Hypervelocity collision and water-rock interaction in space preserved in the Chelyabinsk ordinary chondrite

Eizo Nakamura, Tak Kunihiro, Tsutomu Ota, Chie Sakaguchi, Ryoji Tanaka, Hiroshi Kitagawa, Katsura Kobayashi, Masahiro Yamanaka, Yuri Shimaki, Gray E. Bebout, Hitoshi Miura, Tetsuo Yamamoto, Vladimir Malkovets, Victor Grokhovsky, Olga Koroleva, Konstantin Litasov

Research output: Contribution to journalArticle

Abstract

A comprehensive geochemical study of the Chelyabinsk meteorite reveals further details regarding its history of impact-related fragmentation and melting, and later aqueous alteration, during its transit toward Earth. We support an 930Ma age obtained by Ar-Ar method (Beard et al., 2014) for the impact-related melting, based on Rb-Sr isotope analyses of a melt domain. An irregularly shaped olivine with a distinct O isotope composition in a melt domain appears to be a fragment of a silicate-rich impactor. Hydrogen and Li concentrations and isotopic compositions, textures of Fe oxyhydroxides, and the presence of organic materials located in fractures, are together consistent with aqueous alteration, and this alteration could have pre-dated interaction with the Earth's atmosphere. As one model, we suggest that hypervelocity capture of the impact-related debris by a comet nucleus could have led to shock-wave-induced supercritical aqueous fluids dissolving the silicate, metallic, and organic matter, with later ice sublimation yielding a rocky rubble pile sampled by the meteorite.

Original languageEnglish
Pages (from-to)165-177
Number of pages13
JournalProceedings of the Japan Academy Series B: Physical and Biological Sciences
Volume95
Issue number4
DOIs
Publication statusPublished - 2019

Keywords

  • Asteroid
  • Chronology
  • Comet
  • Geochemistry
  • Impact melting
  • Ordinary chondrite

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Physics and Astronomy(all)

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