地球の基礎マントルの異常の原因である月形成インパクター
Qian Yuan1,2, Mingming Li3, Steven J Desch3
1School of Earth and Space Exploration, Arizona State University, Tempe, AZ, USA. qyuan@caltech.edu.
Nature
|November 2, 2023
まとめ
地球の大きな低速度領域 (LLVP) は,月を形成した原惑星テアからの物質の残骸である可能性があります. この古代のマントルの物質は 地球の奥深くにある構造の組成を説明します
科学分野:
- 地理学
- 惑星科学
- 地球科学
背景:
- 地球の最も下層のマントルには 大陸サイズの異変があり 低速度領域 (LLVP) と呼ばれています
- LLVPは通常,マントル内の密度が高く,構成が異なる異質性として解釈されます.
研究 の 目的:
- LLVPsが月形成の巨大衝突からのテアマントルの物質 (TMM) の残骸であるかどうかを調査する.
- 地球のマントルのTMMの保存と蓄積をモデル化するために
主な方法:
- テイアから原地球への物質の輸送をモデル化する 巨大衝突シミュレーション
- 地質学的時間における密度の高いTMMの振る舞いを追跡するためのマントルのコンベクションモデリング.
主要な成果:
- シミュレーションによると テイアのマントルの一部は 原地球の下層マントルに組み込まれていた可能性がある.
- テイアのマントルは原地球より2.0~3.5%密度が高いと推定されている.
- 密度の高いTMMの塊は沈み,コアマントルの境界に蓄積し,今日まで存在するLLVPのような構造を形成します.
結論:
- LLVPは月を形成した巨大衝突の直接的な結果であり,セアマントルの保存された物質を表しています.
- この衝突による起源は,他の惑星の体にも同様のマントルの異質性があることを示唆している.
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