Chemical mapping of proterozoic organic matter at submicron spatial resolution.
Chemical mapping of proterozoic organic matter at submicron spatial resolution.
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亚微米空间分辨率的元古代有机质化学图。
DOI：
10.1089/ast.2006.6.838
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发表时间：
2006
期刊：
影响因子：
4.2
通讯作者：
D. Mckay
中科院分区：
文献类型：
--
作者：
D. Oehler;F. Robert;S. Mostefaoui;A. Meibom;M. Sélo;D. Mckay
一个NanoSIMS离子微探针被用来映射碳，氮，硫，硅，和氧的亚微米级分布在有机微化石和薄层在薄的一部分，约0.85亿年的澳大利亚苦泉组。这些数据提供了有关微体化石的原始化学，硅化过程以及特定微生物和微生物群落的生物特征的线索。化石单细胞和细丝的化学图谱显示了不同的壁和鞘状结构，富含C，N和S，与它们公认的生物起源一致。令人惊讶的是，有机层，以前被认为是无定形的，也表现出丝状和明显的压缩球状结构，由强烈富集的C，N和S定义。通过类比保存完好的微化石的NanoSIMS数据，这些结构被解释为生物起源，最有可能代表密集的微生物垫残余。考虑到前寒武纪沉积物中有机质的优势同样是“无定形的”，我们的研究结果表明，通过原位结构，化学和同位素研究重新评估古代标本是必要的。我们的分析使我们提出了新的标准来评估有问题的干酪根物质的生物性，因此，这些标准可以应用于评估保存不良或破碎的有机残留物在早期太古代沉积物和任何可能发生在陨石或其他外星样品。
A NanoSIMS ion microprobe was used to map the submicron-scale distributions of carbon, nitrogen, sulfur, silicon, and oxygen in organic microfossils and laminae in a thin section of the approximately 0.85 billion year old Bitter Springs Formation of Australia. The data provide clues about the original chemistry of the microfossils, the silicification process, and the biosignatures of specific microorganisms and microbial communities. Chemical maps of fossil unicells and filaments revealed distinct wall- and sheath-like structures enriched in C, N, and S, consistent with their accepted biological origin. Surprisingly, organic laminae, previously considered to be amorphous, also exhibited filamentous and apparently compressed spheroidal structures defined by strong enrichments in C, N, and S. By analogy to NanoSIMS data from the well-preserved microfossils, these structures were interpreted as being of biological origin, most likely representing densely packed remnants of microbial mats. Given that the preponderance of organic matter in Precambrian sediments is similarly "amorphous," our findings indicate that a re-evaluation of ancient specimens via in situ structural, chemical, and isotopic study is warranted. Our analyses have led us to propose new criteria for assessing the biogenicity of problematic kerogenous materials, and, thus, these criteria can be applied to assessments of poorly preserved or fragmentary organic residues in early Archean sediments and any that might occur in meteorites or other extraterrestrial samples.
DOI：
--
发表时间：
2004
期刊：
Geochimica et Cosmochimica Acts 68
影响因子：
--
作者：
Ueno Y.;Yoshioka H.;Maruyama S.;Isozaki Y.
通讯作者：
Isozaki Y.