Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars.
Organic molecules in the Sheepbed Mudstone, Gale Crater, Mars.
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DOI：
10.1002/2014je004737
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发表时间：
2015-03
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影响因子：
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通讯作者：
Zorzano MP
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作者：
Freissinet C;Glavin DP;Mahaffy PR;Miller KE;Eigenbrode JL;Summons RE;Brunner AE;Buch A;Szopa C;Archer PD;Franz HB;Atreya SK;Brinckerhoff WB;Cabane M;Coll P;Conrad PG;Des Marais DJ;Dworkin JP;Fairén AG;François P;Grotzinger JP;Kashyap S;Ten Kate IL;Leshin LA;Malespin CA;Martin MG;Martin-Torres FJ;McAdam AC;Ming DW;Navarro-González R;Pavlov AA;Prats BD;Squyres SW;Steele A;Stern JC;Sumner DY;Sutter B;Zorzano MP
火星科学实验室好奇号火星车上的火星样本分析（SAM）仪器旨在对大气、表面风化层和岩石进行无机和有机化学分析，以帮助评估火星盖尔陨石坑过去和现在的宜居性。这项任务的核心是开发任何存在的有机分子的清单，以阐明与它们的起源、成岩作用、浓度和长期保存相关的过程。这将指导未来对生物特征的研究。在这里，我们报告了使用SAM气相色谱质谱（GCMS）和直接演化气体分析（EGA）模式在来自Yellowknife湾Sheepbed泥岩的Cumberland钻孔的多个部分的细粒中最终鉴定出氯苯（150-300 ppbw）和C2至C4二氯烷烃（高达70 ppbw）。当结合从多个挖取和钻取样品、空白运行和辅助实验室模拟研究中获得的GCMS和EGA数据时，氯苯和二氯烷烃水平的升高不能仅仅由已知存在于SAM中的仪器背景源来解释。我们得出结论，这些氯化碳氢化合物是火星氯和有机碳的反应产物，这些有机碳来自火星来源（如火成岩、热液、大气或生物）或外源，如陨石、彗星或行星际尘埃颗粒。首次在火星表面沉积物中发现非陆地有机物的原位证据。SAM在羊床泥岩中发现氯代烃。暴露于电离辐射和氧化条件下的有机物保存在样品中
The Sample Analysis at Mars (SAM) instrument on board the Mars Science Laboratory Curiosity rover is designed to conduct inorganic and organic chemical analyses of the atmosphere and the surface regolith and rocks to help evaluate the past and present habitability potential of Mars at Gale Crater. Central to this task is the development of an inventory of any organic molecules present to elucidate processes associated with their origin, diagenesis, concentration, and long-term preservation. This will guide the future search for biosignatures. Here we report the definitive identification of chlorobenzene (150–300 parts per billion by weight (ppbw)) and C2 to C4 dichloroalkanes (up to 70 ppbw) with the SAM gas chromatograph mass spectrometer (GCMS) and detection of chlorobenzene in the direct evolved gas analysis (EGA) mode, in multiple portions of the fines from the Cumberland drill hole in the Sheepbed mudstone at Yellowknife Bay. When combined with GCMS and EGA data from multiple scooped and drilled samples, blank runs, and supporting laboratory analog studies, the elevated levels of chlorobenzene and the dichloroalkanes cannot be solely explained by instrument background sources known to be present in SAM. We conclude that these chlorinated hydrocarbons are the reaction products of Martian chlorine and organic carbon derived from Martian sources (e.g., igneous, hydrothermal, atmospheric, or biological) or exogenous sources such as meteorites, comets, or interplanetary dust particles. First in situ evidence of nonterrestrial organics in Martian surface sediments Chlorinated hydrocarbons identified in the Sheepbed mudstone by SAM Organics preserved in sample exposed to ionizing radiation and oxidative condition