在火星表面的现场放射测定和曝光年龄测定
K A Farley1, C Malespin, P Mahaffy
1Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Science (New York, N.Y.)
|December 11, 2013
概括
盖尔火山口的古代火星泥石揭示了K-Ar年龄为421亿年. 它的表面暴露年龄为7800万年,表明最近的埋葬和暴露,保留了潜在的有机生物标志物.
科学领域:
- 地质地质地质地质地质地
- 行星科学 行星科学
- 地质化学 地质化学
背景情况:
- 火星上的盖尔火山口是了解火星地质历史的关键地点.
- 贵重气体地化学为火星岩石的年龄和暴露历史提供了洞察力.
研究的目的:
- 为了确定盖尔火山口中的泥石的年龄和表面暴露历史.
- 评估暴露沉积岩中有机生物标记物保存的潜力.
主要方法:
- 放射性 (K-Ar) 和宇宙性 (He,Ne,Ar) 贵气的分析.
- 地化学测年技术,以确定年龄和暴露时间.
主要成果:
- 确定泥石的K-Ar年龄为4.21 ± 0.35亿年.
- 宇宙起源的贵重气体表明表面暴露年龄为78±300万年.
- 这些发现表明,先前埋藏的沉积岩石最近暴露.
结论:
- 泥石的年龄证实了盖尔坑边缘的古老性质.
- 表面暴露发生在当前的地形环境中,而不是在初级运输过程中.
- 风力驱动的侵蚀暴露了沉积岩,可能保护有机生物标志物免受辐射损害.
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