Two extraterrestrial dust horizons found in the Dome Fuji ice core, East Antarctica

Keiji Misawa, Mika Kohno, Takayuki Tomiyama, Takaaki Noguchi, Tomoki Nakamura, Keisuke Nagao, Takashi Mikouchi, Kunihiko Nishiizumi

研究成果: ジャーナルへの寄稿学術誌査読

15 被引用数 (Scopus)

抄録

Two silicate-rich dust layers were found in the Dome Fuji ice core in East Antarctica, at Marine Isotope Stages 12 and 13. Morphologies, textures, and chemical compositions of constituent particles reveal that they are high-temperature melting products and are of extraterrestrial origin. Because similar layers were found ∼ 2000 km east of Dome Fuji, at EPICA (European Project for Ice Coring in Antarctica)-Dome C, particles must have rained down over a wide area 434 and 481 ka. The strewn fields occurred over an area of at least 3 × 106 km2. Chemical compositions of constituent phases and oxygen isotopic composition of olivines suggest that the upper dust layer was produced by a high-temperature interaction between silicate-rich melt and water vapor due to an impact explosion or an aerial burst of a chondritic meteoroid on the inland East Antarctic ice sheet. An estimated total mass of the impactor, on the basis of particle flux and distribution area, is at least 3 × 109 kg. A possible parent material of the lower dust layer is a fragment of friable primitive asteroid or comet. A hypervelocity impact of asteroidal/cometary material on the upper atmosphere and an explosion might have produced aggregates of sub-μm to μm-sized spherules. Total mass of the parent material of the lower layer must exceed 1 × 109 kg. The two extraterrestrial horizons, each a few millimeters in thickness, represent regional or global meteoritic events not identified previously in the Southern Hemisphere.

本文言語英語
ページ(範囲)287-297
ページ数11
ジャーナルEarth and Planetary Science Letters
289
1-2
DOI
出版ステータス出版済み - 1月 15 2010
外部発表はい

!!!All Science Journal Classification (ASJC) codes

  • 地球物理学
  • 地球化学および岩石学
  • 地球惑星科学(その他)
  • 宇宙惑星科学

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