Amino acids in Antarctic CM1 meteorites and their relationship to other carbonaceous chondrites
Amino acids in Antarctic CM1 meteorites and their relationship to other carbonaceous chondrites
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DOI：
10.1111/j.1945-5100.2007.tb00219.x
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发表时间：
2007-01-01
影响因子：
2.2
通讯作者：
Ehrenfreund, Pascale
中科院分区：
文献类型：
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作者：
Botta, Oliver;Martins, Zita;Ehrenfreund, Pascale
CM2 碳质球粒陨石是太阳系中存在的最原始的物质，它们的一些亚型（CM 和 CI 球粒陨石）含有高达 2 wt% 的有机碳。 CM2 碳质球粒陨石含有多种复杂的氨基酸，而 CI 陨石 Orgueil 和 Ivuna 显示出更简单的成分，仅含有大量的甘氨酸和 β-丙氨酸。 CM1 碳质球粒陨石表现出比 CM2 类型更高程度的水蚀变，因此在 CM2 和 CI1 碳质球粒陨石之间提供了重要的联系。相对氨基酸浓度已被证明可以指示母体有关此类化合物形成的过程。为了了解这三类陨石之间的氨基酸组成之间的关系，我们首次使用气相色谱-质谱（GC-MS）和高效液相色谱-荧光检测（HPLC-FD）分析了三块南极CM1球粒陨石：陨石山（MET）01070、艾伦山（ALH）88045和拉巴斯冰原（LAP）02277。这些陨石中八种最丰富氨基酸的浓度与 CM2 Murchison、Murray、Mighei、Lewis Cliff (LEW) 90500、ALH 83100 以及 CI1 Orgueil 和 Ivuna 的浓度进行了比较。发现 CM1 碳质球粒陨石中的总氨基酸浓度远低于 CM2 的平均值。比较相对氨基酸丰度，以确定这些陨石类别中氨基酸组成之间的合成关系。我们的数据支持这样的假设：CM 型和 CI 型陨石中的氨基酸是在不同的物理和化学条件下合成的，最好的解释可能是其母体来源区域中前体化合物丰度的差异以及长期水蚀过程中氨基酸的分解。
CM2 carbonaceous chondrites are the most primitive material present in the solar system, and some of their subtypes, the CM and CI chondrites, contain up to 2 wt% of organic carbon. The CM2 carbonaceous chondrites contain a wide variety of complex amino acids, while the CI meteorites Orgueil and Ivuna display a much simpler composition, with only glycin, and beta-alanine present in significant abundances. CM1 carbonaceous chondrites show a higher degree of aqueous alteration than CM2 types and therefore provide an important link between the CM2 and CI1 carbonaceous chondrites. Relative amino acid concentrations have been shown to be indicative for parent body processes with respect to the formation of this class of compounds. In order to understand the relationship of the amino acid composition between these three types of meteorites, we have analyzed for the first time three Antarctic CM1 chondrites, Meteorite Hills (MET) 01070, Allan Hills (ALH) 88045, and LaPaz Icefield (LAP) 02277, using gas chromatography-mass spectrometry (GC-MS) and high performance liquid chromatography-fluorescence detection (HPLC-FD). The concentrations of the eight most abundant amino acids in these meteorites were compared to those of the CM2s Murchison, Murray, Mighei, Lewis Cliff (LEW) 90500, ALH 83100, as well as the CI1 Orgueil and Ivuna. The total amino acid concentration in CM1 carbonaceous chondrites was found to be much lower than the average of the CM2s. Relative amino acid abundances were compared in order to identify synthetic relationships between the amino acid compositions in these meteorite classes. Our data support the hypothesis that amino acids in CM- and CI-type meteorites were synthesized under different physical and chemical conditions and may best be explained with differences in the abundances of precursor compounds in the source regions of their parent bodies in combination with the decomposition of amino acids during extended aqueous alteration.