ルビジアム・ストロンチウムの年齢と,月面のサンプルにおけるいくつかの微量元素の元素および同位体の豊富さ
まとめ
月面の結晶岩は,ルビジアム・ストロンチウム (Rb-Sr) の同位相年代測定を用いて,44億2千万年という年齢を明らかにしている. この研究では,月の岩石形成と中性子の流れを理解するために元素の豊富さも分析しました.
科学分野:
- 地質化学 地質化学
- 宇宙化学 (コスモケミストリー)
- ラジオメトリック・デッティング
背景:
- 月の結晶岩は,月の初期の歴史と進化の洞察を提供します.
- 月面サンプルの組成と年齢を理解することは,惑星科学にとって極めて重要です.
研究 の 目的:
- ルビジアム・ストロンチウム (Rb-Sr) の同位年代測定を用いて月の結晶岩の年齢を決定する.
- 基本的多量分析を通じて,これらの月面のサンプルの石油生成を調査する.
- 月面物質が経験する統合熱中性子フクロスを制限するために.
主な方法:
- Rb-Srイソクロン法を用いた放射線年代測定.
- 元素の豊富度 (K,Rb,Sr,Ba,Eu,Gd) の分析について
- 月面のサンプル組成と地上の材料の比較.
主要な成果:
- 6つの月の結晶岩で,4.42 ± 0.24 x 10^9年というRb-Srアイソクロン年齢が得られた.
- 初期ストロンチウム同位体比 ((87) Sr/ ((86) Sr) は,玄武岩アコンドライトの同位体比に似ていることが判明した.
- 証拠は,岩石形成中に溶融からプラジオクラスが分離することを示唆しています.
- ガドリニウム157 (Gd-157) の豊富さは,月面と地上の材料間の統合された熱中性子流量差を1平方センチメートルあたり<6 x 10^15の中性子に制限する.
結論:
- 決定された年齢は,これらの月の岩石の非常に初期の形成を示しています.
- プラジオクラゼの分離は,これらの月の溶融の進化における重要なプロセスです.
- この研究は,月面のサンプルで経験される中性子流の制約を提供し,宇宙気象と同位体進化を理解するために重要である.
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