月面隕石の衝突による月面大災害仮説の裏付けは,月面隕石の衝突による融解年齢によるものです
B A Cohen1, T D Swindle, D A Kring
1The University of Arizona, Tucson, AZ 85721, USA. bcohen@utk.edu
Science (New York, N.Y.)
|January 11, 2000
まとめ
月面の隕石は,地球と月のシステムに関する新しい洞察を提供します. 分析は,約39億年前の短い,激しい爆撃期間を明らかにし,月面の大災害仮説を支持しています.
科学分野:
- 地質学 地質学 地質学
- 惑星科学は惑星科学である.
- コスミックインパクト研究 (Cosmic Impact Studies) とは,宇宙の影響に関する研究です.
背景:
- 月面隕石は,アポロとルナのコレクションと比較して,月面物質のよりランダムなサンプルを提供します.
- 月面大災害の仮説を再検討することは,太陽系の初期の歴史を理解するために極めて重要です.
研究 の 目的:
- 月の隕石の衝突を分析するために,月面の大災害仮説を再評価するために,月面隕石の衝突で融解する年齢を分析します.
- 地球・月系における古代の爆撃事件のタイミングと強度を決定する.
主な方法:
- 月面隕石 (MAC 88105, QUE 93069, DaG 262, DaG 400) から採取した衝突溶融サンプルに40Ar-39Arの年代測定法を使用した.
- 隕石のブレキアで表される7〜9つの異なる衝撃イベントを分析した.
主要な成果:
- 決定された衝撃融解年齢は276億年から392億年前です.
- 観測された衝突による融解の欠如は,392億年以上前のものです.
結論:
- この発見は,約39億年前の短い,激しい衝撃爆撃期間のモデルを裏付けている.
- この期間は,衝突活動の異常なピークを表し,一般的に減少する衝突周波数曲線とは異なる.
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