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

• Published in: Nuclear Engineering and Technology
• Main Authors: Shun Sekimoto, Takayuki Kobayashi, Koichi Takamiya, Mitsuru Ebihara, Seiichi Shibata
• Format: Article in Journal/Newspaper
• Language: English
• Published: Elsevier 2016
• Subjects: Antarctic; Extraterrestrial; Iridium; Neutron Activation Analysis; Spherule; Nuclear engineering. Atomic power; TK9001-9401; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://doi.org/10.1016/j.net.2016.02.004; https://doaj.org/article/f4291d41fb9140889b0f1b11236f50a6

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.