まとめ
インブリウム衝突の出来事とインブリウム以前の玄武岩の結晶化は同時に起こった. フレマウロ岩のアルゴン-40/アルゴン-39年代測定は,この37億7千万年前の出来事を確認しています.
科学分野:
- 月面地質学 月面地質学
- コスミックインパクトイベントは,宇宙のインパクトイベントです.
- 放射線年代測定法による年代測定
背景:
- フラ・マウロ形成は,月面の重要な地質学的単位であり,インブリウム衝突から放出されたものと考えられています.
- 月面の地質学的な出来事のタイミングを理解することは,月面の歴史と太陽系の初期段階の解読に不可欠です.
研究 の 目的:
- フラ・マウロ形成の岩石の結晶化年齢を決定するために.
- インブリウム衝突の出来事と月の玄武岩結晶化の間の時間的関係を確立するために.
主な方法:
- アルゴン-40/アルゴン-39 (Ar-40/Ar-39) 増量加熱およびレーザーアブレーション質量スペクトロメトリ.
- フラ・マウロから採取した月の岩石の6つのサンプルを放射測定で年代測定した.
主要な成果:
- 分析した6つの岩石すべては,一貫した結晶化年齢が3.77 ± 0.15億年であった.
- この年齢は,同じ場所からの断片的な岩石の以前に決定された年齢と同一です.
結論:
- インブリウム衝突の出来事と,インブリウム以前の月の玄武岩の大部分の結晶化は,同時に起こった.
- この発見は,月面衝突の歴史と初期の火山活動に関する重要な年代データを提供します.
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