How to Search for Life in Martian Chemical Sediments and Their Fluid and Solid Inclusions Using Petrographic and Spectroscopic Methods
How to Search for Life in Martian Chemical Sediments and Their Fluid and Solid Inclusions Using Petrographic and Spectroscopic Methods
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DOI：
10.3389/fenvs.2019.00108
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发表时间：
2019-07-16
影响因子：
4.6
通讯作者：
Benison, Kathleen C.
中科院分区：
文献类型：
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作者：
Benison, Kathleen C.
在寻找火星上的生命方面，已经投入了大量的资源和努力。探测器、着陆器和漫游者已经测试了大气气体、一般沉积物和岩石成分，以及火星表面的图像，以探测任何可能的现代或古代生命留下的生物特征。在火星上发现了氯化物和硫酸盐矿物，暗示着过去的酸性盐湖。在陆地酸性盐水环境中，这些矿物捕获微生物和有机化合物，并将它们保存在流体包裹体中，并作为固体包裹体保存很长的地质时期。一些细胞仍然存活，特别是在流体包裹体的孤立的微观含水环境中。火星上这些盐矿物中的流体包裹体还有待研究。本文介绍了最近用来探测和鉴定保存在现代和二叠纪类似火星的酸性盐湖岩盐和石膏中的微生物和有机化合物的岩相学和地球化学方法。然后，它提出了建议，如何火星化学沉积物可以检查这些生物特征，无论是由火星车和返回的样本。这项用于检查火星化学沉积物和沉积岩的新协议可能为检测火星上任何保存的生物特征提供下一步。
Abundant resources and efforts have been employed in the search for life on Mars. Satellites, landers, and rovers have tested atmospheric gases, general sediment and rock compositions, and images of Mars surface in an effort to detect biosignatures left by any possible modern or ancient life. Chloride and sulfate minerals suggestive of past acid saline lakes have been found on Mars. In terrestrial acid brine environments, these minerals trap microorganisms and organic compounds and preserve them within fluid inclusions and as solid inclusions for long geologic time periods. Some cells remain viable, especially in the isolated, microscopic aqueous environments of fluid inclusions. Fluid inclusions in these same saline minerals on Mars have yet to be examined. This paper describes petrographic and geochemical methods that have been used recently to detect and make general identifications of microorganisms and organic compounds preserved in modern and Permian Mars-analog acid saline lake halite and gypsum. It then makes recommendations for how Martian chemical sediments could be examined for these biosignatures, both by rovers and in returned samples. This new protocol for the examination of Martian chemical sediments and sedimentary rocks may provide the next step for detection of any preserved biosignatures on Mars.