堆積物で散らばった地外生命体クロミットは,大型の小惑星破壊イベントの痕跡を示しています
Birger Schmitz1, Therese Häggström, Mario Tassinari
1Department of Earth Science, Rice University, Post Office Box 1892, Houston, TX 77251, USA. birger@gvc.gu.se
Science (New York, N.Y.)
|May 10, 2003
まとめ
スウェーデンの石灰岩で発見された豊富な地外クロミット粒は,4億8千万年前に地球に流出した隕石の量が大幅に増加したことを示しています. この発見は,小惑星の衝突と地球外物質の配送に関する新しい洞察を提供します.
科学分野:
- 地質学 地質学 地質学
- 惑星科学 惑星科学
- パレオントロジー・パレオントロジー
背景:
- スウェーデン南部のオルドビキア期中期の海洋石灰岩には,地球外のクロマイト粒子が豊富に含まれています.
- これらの粒子は,分解した隕石から発生し,約4億8千万年前に遡ります.
- 以前の研究では,オルドビシアン中期に隕石の流入が著しく増加したことを示していた.
研究 の 目的:
- オルドビケ紀中期の石灰岩のクロミット異常を調査するために.
- 地球への隕石の流入が増えた証拠を提供するために.
- 主要な小惑星破壊イベントの後の地球外物質フルースの時間的な変動を制限するために.
主な方法:
- クロミット粒子の地化学分析.
- 石灰岩堆積地の地質地図作成.
- 古代気候と天体物理学のデータとの相関.
主要な成果:
- 25万平方キロメートルの土地で豊富な地外クロミット粒子の発見.
- クロミット異常は,隕石の流入が2桁増加することを支持しています.
- 地球外物質の流れに関する詳細な時間的制約を提供します.
結論:
- オールドビキア期中期は,隕石の爆撃率が著しく上昇した.
- このイベントは,小惑星帯の大規模な小惑星破壊によって引き起こされた可能性が高い.
- 異星人のクロマイトは,地球の衝突の歴史を理解するための貴重なプロキシとして機能します.
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