Amino acid composition, petrology, geochemistry, 14C terrestrial age and oxygen isotopes of the Shişr 033 CR chondrite
Amino acid composition, petrology, geochemistry, 14C terrestrial age and oxygen isotopes of the Shişr 033 CR chondrite
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Shişr 033 CR 球粒陨石的氨基酸组成、岩石学、地球化学、14C 地球年龄和氧同位素
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发表时间：
2007
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通讯作者：
P. Ehrenfreund
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作者：
Z. Martins;B. Hofmann;E. Gnos;R. Greenwood;A. Verchovsky;I. Franchi;A. Jull;O. Botta;D. Glavin;J. Dworkin;P. Ehrenfreund
摘要-我们用几种不同的分析技术对来自阿曼沙漠的CR球粒陨石Shihşr033进行了分析，目的是研究这块陨石的陆地蚀变程度和岩石学分类。批量化学分析(包括有机碳和平均总H2O含量)与CR分类一致。此外，大块样品的氧同位素分析表明，Shiişr033属于CR2型。氨基酸分析结果表明，Shihşr033的绝对氨基酸和相对氨基酸含量与其他碳质球粒陨石不同。富含层状硅酸盐的暗色包体的氧同位素分析表明，该包体更接近于CV3或CO3球粒陨石。从暗包裹体碳同位素数据、整体化学(通过升高的锶和钡的浓度)和氨基酸数据可以明显地看出Shihşr033中陆地风化的影响，这表明陨石在秋季土壤中受到了广泛的氨基酸污染。然而，Shihşr033含有一小部分本地成分，这是因为存在在Shiişr土壤中未检测到的地外氨基酸AiB。最后，确定了Shihşr033的地球年龄，并在高污染的背景下进行了讨论。
Abstract— We have analyzed Shişr 033, a CR chondrite from the Omani desert, using several different analytical techniques designed to study the degree of terrestrial alteration of this meteorite and also its petrologic classification. Bulk chemical analyses (including organic carbon and mean total H2O content) are consistent with a CR classification. Additionally, oxygen isotope analysis on a bulk sample indicates that Shişr 033 is of type CR2. Amino acid analysis using liquid chromatography with UV fluorescence detection (HPLC‐FD) and liquid chromatography‐time of flight‐mass spectrometry (LC‐ToF‐MS) show that the absolute and the relative amino acid content of Shişr 033 is distinct from other carbonaceous chondrites. Oxygen isotope analysis of a phyllosilicate‐rich dark inclusion shows that this inclusion is closer to CV3 or CO3 chondrites. The effects of terrestrial weathering in Shişr 033 are evident from the dark inclusion carbon isotopic data, bulk chemistry (through the elevated concentrations of Sr and Ba), and amino acid data, which suggests extensive amino acid contamination of the meteorite from the fall site soil. Nevertheless, Shişr 033 contains a small fraction of indigenous components, as indicated by the presence of the extraterrestrial amino acid α‐aminoisobutyric acid (AIB) that was not detected in the Shişr soils. Finally, the terrestrial age of Shişr 033 was determined and is discussed in the context of high levels of contamination.