火星のステップ・デルタ形成は,急速な水放出によるものです
Erin R Kraal1, Maurits van Dijk, George Postma
1Faculty of Geosciences, Utrecht University, Postbus 80115, 3508 TC, Utrecht, The Netherlands. ekraal@vt.edu
Nature
|February 22, 2008
まとめ
火星の段階的なデルタは,地表水が数百万年ではなく数十年間しか流れなかったことを示唆しています. この発見は,火星に新たな制約を与える.
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
- 水文学 水文学とは
背景:
- 火星のデルタや流水扇は,過去の地表水流の重要な指標である.
- 以前の形態学的研究は,火星の水文学的出来事のための広範な時間推定 (数十年から数百万年) を提供しました.
- 火星のデルタの形成を理解することは,惑星の水の歴史を再構築するために不可欠です.
研究 の 目的:
- 異なる火星のステップ (テラス) デルタの形成の時間スケールを調査するために.
- 火星上の過去の地表水の流れの期間と大きさを制限するために.
主な方法:
- デルタ形成をシミュレートするために,砂流の実験を活用しました.
- 形成過程と時間尺度を推論するために,結果の形態論を分析した.
主要な成果:
- 火星の段階的なデルタは,おそらく単一の盆地充填イベントから形成された.
- この出来事は,数十年と推定される短い期間で起こった.
- 必要な水量は,ミシシッピ川のような大陸の川に匹敵する.
結論:
- 段階的なデルタは,いくつかの火星表面の流れの持続時間に対する最小限と最大限の両方の制約を提供します.
- この発見は,地下貯蔵から水が突然放出されたという仮説を裏付けている.
- この急速な放出により,おそらく流の扇風機の上にテラス状のデルタ堆積物が形成された.
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