Origin of Spherule Samples Recovered from Antarctic Ice Sheet-Terrestrial or Extraterrestrial?

Shun Sekimoto*, Takayuki Kobayashi, Koichi Takamiya, Mitsuru Ebihara, Seiichi Shibata

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Thirty-eight spherules from the Antarctic ice sheet were analyzed using neutron activation analysis under two different conditions to investigate their origin. In almost all of these spherules, the contents of iron, cobalt, and manganese were determined to be 31% to 88%, 17 mg/kg to 810 mg/kg, and 0.017% to 7%, respectively. A detectable iridium content of 0.84 mg/kg was found in only one spherule, which was judged to be extraterrestrial in origin. A comparison of elemental compositions of the Antarctic spherules analyzed in this study with those of deep-sea sediment spherules and those of terrestrial materials revealed that most of the Antarctic spherules except for the sample in which iridium was detected could not be identified as extraterrestrial in origin.

Original languageEnglish
Pages (from-to)293-298
Number of pages6
JournalNuclear Engineering and Technology
Issue number2
Publication statusPublished - 2016 Apr 1
Externally publishedYes


  • Antarctic
  • Extraterrestrial
  • Iridium
  • Neutron Activation Analysis
  • Spherule

ASJC Scopus subject areas

  • Nuclear Energy and Engineering


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