Procellarum KREEP TerraneのChang'e-5ベザルトのKREEP以外の起源について
Heng-Ci Tian1, Hao Wang2, Yi Chen2
1Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
Nature
|October 19, 2021
まとめ
Procellarum KREEP Terrane (PKT) の若い月の玄武岩は,KREEPではないマントルの源を明らかにしています. この 発見 は,月 の 起源 に 関する 以前 の 推測 に 異議 を 唱え ます
科学分野:
- 月の地質学
- 惑星科学
- 地化学
背景:
- 月の熱と化学の進化を理解するために 月の塩基岩は極めて重要です
- 若い玄武岩は,以前は,KREEPが豊富なマントルの源泉から発生すると考えられていたProcellarum KREEP Terrane (PKT) に集中しています.
- これらの若い玄武岩の起源は,直接的な研究が不足しているため,議論されている.
研究 の 目的:
- チェンジ5号が帰還した PKTの青い塩基岩を 石油と地質学的に分析する
- KREEPが豊富な源から PKTの若い玄武岩が形成されたという仮説を検証する.
- 月の内部の熱的進化を調査する
主な方法:
- 月面の塩基岩の石油学と地化学分析
- 大量の岩石の組成分析 (チタン,鉄,稀土元素,トリウム)
- ストロンチウム・ネオジミウム同位体分析
主要な成果:
- 研究されたバザルトは 20億年前のもので 最新の月面サンプルです
- 大量組成は中程度のチタン,高い鉄,およびKREEPのような希土元素とトリウム濃度を示しています.
- ストロンチウム-ネオジムイソトープは,低度部分溶解と小分結晶化を必要とする,KREEP以外のマントル源から派生することを示す.
結論:
- KREEPの結成は必ずしも若い馬の火山活動の前提条件ではない.
- 月の最年少の融解は,熱生成要素を必要とせずに,持続的な内部冷却の歴史によって生成されます.
- この研究は,月の熱進化とマントルの過程についての理解を修正します.
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