火星フェニックス着陸地でのカルシウム炭酸の証拠
W V Boynton1, D W Ming, S P Kounaves
1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. wboynton@LPL.Arizona.edu
まとめ
カルシウム炭酸は火星の土壌で発見され,過去の液体の水の活動を示しています. この発見は,火星上の古代の水の証拠を提供し,その地質の歴史を理解するために不可欠です.
科学分野:
- 惑星科学 惑星科学
- 天体生物学 アストロバイオロジー
- 地質化学 地質化学
背景:
- 炭酸塩は,惑星の表面における過去の水性過程の重要な指標である.
- 火星の地質学的歴史を理解するには,過去の水の証拠を特定することに依存しています.
- 以前のミッションでは,水と火星の居住可能性の証拠を求めた.
研究 の 目的:
- フェニックス着陸地点付近の火星の土壌におけるカルシウム炭酸を特定し,定量化するために.
- 過去の火星水の歴史における検出されたカルシウム炭酸の形成条件と影響を決定する.
主な方法:
- 鉱物学的移行を検出するためにスキャニングカロミテリーを使用した.
- 約725°Cでの内熱変異と二酸化炭素の進化の分析.
- 酸添加に対する土壌pHのバッファリング能力の評価.
主要な成果:
- カルシウム炭酸は,火星の土壌で識別され,重量3~5%で存在していた.
- この鉱物は,CO2の放出とともに,約725°Cの内熱的移行を示した.
- 土壌は,重要なpHバッファリング能力を示した.
結論:
- カルシウム炭酸の存在と量は,大気中のCO2と表面液体の水膜の相互作用による形成と一致しています.
- この発見は,火星の表面で過去に液体の水の活動があったという仮説を強く支持しています.
- 結果は,火星の古代の気候と潜在的な居住可能性に関する貴重な洞察を提供します.
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