火星での水関連の地質学的な活動について詳しく見てみる
A S McEwen1, C J Hansen, W A Delamere
1Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, USA. mcewen@lpl.arizona.edu
まとめ
証拠は,水が火星を改造したことを示唆しています.
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
- 天体生物学 アストロバイオロジー
背景:
- 火星の表面は,過去の水活動を示唆する地形を示しています.
- これらの特徴を解釈することは,火星の歴史を理解するために極めて重要です.
研究 の 目的:
- 火星上の水の証拠を,高空間解像度で調査する.
- 海洋堆積物や活発な渓谷などの火星表面特性の解釈を再評価する.
主な方法:
- 高解像度画像科学実験 (HiRISE) を利用し,火星偵察軌道に乗った.
- ピクセルあたり25〜32センチメートルの空間スケールの画像を分析しました.
- 中高緯度および赤道地域における岩石の分布と溝の堆積を調査した.
主要な成果:
- 中高緯度で観測された至る所に存在する岩石 (最大2m) は,細粒子の堆積物や雪に関する以前の解釈に異議を唱える.
- 急な斜面 (20〜35度) に近年の明るい溝の堆積物が特定され,乾燥質量の浪費と一致しています.
- 地質学的に最近の中緯度渓谷と赤道衝突クレーターで,流域の変化の証拠が見つかりました.
結論:
- 古代火星の海の存在は未だに確認されていない.
- 現在の溝の活性水は,決定的に証明されていません.
- 地質学的に最近の流河過程は,火星の渓谷やクレーターに変化をもたらしました.
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