火星のシェルゴッタイト隕石の源頭クレーター

Stephanie C Werner¹, Anouck Ody, François Poulet

¹The Centre for Earth Evolution and Dynamics, University of Oslo, Sem Sælandsvei 24, 0371 Oslo, Norway.

Science (New York, N.Y.)

|March 8, 2014

まとめ

火星のモハベクレーターは,シェルゴッタイト隕石の源泉であり,その噴出年齢をクレーターと結びつけている.

科学分野:

惑星科学は惑星科学である.
地質学地質学地質学
宇宙化学 (コスモケミストリー)

背景:

惑星の表面年齢は通常,クレーター数を用いて推定され,隕石の年齢は間接的な制約を提供します.
火星の年代表の重要なグループであるシェルゴッタイト隕石は,歴史的に年齢の不一致を示しています.

研究の目的:

シェルゴッタイト隕石の噴出の原因となる地上の衝突クレーターを特定するために.
火星の表面のクラテリングベースの年齢決定方法を再調整する.

主な方法:

隕石の噴出年齢とクレーター形成年齢の比較分析.
シェルゴッタイトと火星の地形の鉱物学および同位体 (Pb-Pb) 分析.
火星表面の特徴の地質的地図作成と年代測定.

主要な成果:

火星上の500万年未満のモハベクレーター (幅55km) は,シェルゴッタイト隕石の源泉として特定されています.
隕石の噴出とクレーター形成の年代が一致し,鉱物学的データとともに,このリンクが確認されています.
シェルゴッタイトの元の結晶化年齢は古代であり,より若い年齢は同位体リセットに起因する.

結論:

火星のクレーター形成による年齢の決定は,モジャベクレーター-シェルゴッタイトの結合を用いて現場で校正されています.
この再調整により,火星の最も古い地形の絶対年齢は2億年前に後退する.
この研究は,火星の年代表における不一致を解決し,惑星の進化に関する我々の理解を洗練します.

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