火星の初期に二酸化硫黄の気候フィードバックがあった.
Itay Halevy1, Maria T Zuber, Daniel P Schrag
1Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA. ihalevy@fas.harvard.edu
Science (New York, N.Y.)
|December 22, 2007
まとめ
古代の火星は,大気中の二酸化硫黄 (SO2) と硫化水素 (H2S) により,単に二酸化炭素 (CO2) だけでなく,液体の水があった可能性が高い. この火山ガスの混合物により,炭酸塩の形成が妨げられ,初期の火星の気候フィードバックループが異なっていたことが示唆されています.
科学分野:
- 惑星科学は惑星科学である.
- 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:
- 初期の火星は,液体の水と二酸化炭素 (CO2) に富んだ大気を持っていたと考えられています.
- このような条件を示す大規模な炭酸塩堆積物の予想される形成は観察されなかった.
- この不一致は,別の大気および地化学的プロセスが作用していたことを示唆している.
研究 の 目的:
- 火星初期に予想される炭酸塩堆積物が存在しない理由を調査する.
- 液体の水を支える可能性のある代替的な大気組成を提案する.
- 炭酸塩の形成を阻害する地球化学的メカニズムを説明するために.
主な方法:
- 化学と物理の基本的な原理の応用.
- 大気と水循環の相互作用の地球化学モデリング.
- 火山からの放出ガス産物 (SO2とH2S) の分析.
主要な成果:
- 火山で排気された二酸化硫黄 (SO2) と硫化水素 (H2S) は,液体の水のある気候を維持することができる.
- その結果生じる地化学は,炭酸塩鉱物の形成を阻害する.
- これは,地球のCO2サイクルに類似した硫黄ベースの気候フィードバックループを示唆しています.
結論:
- 火星の炭酸塩の欠如は,SO2が豊富な大気によって説明され得る.
- 初期の火星の気候は,硫黄ベースのフィードバックメカニズムによって調節されていたかもしれない.
- これは,二酸化炭素のみが支配する初期の火星の大気という伝統的な見解に異議を唱える.
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