Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Universités - CNRS UMR 7590, Muséum National d'Histoire Naturelle, UPMC Univ. Paris 06, IRD UMR 206, 61 rue Buffon, 75005, Paris, France.
Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
Sci Rep. 2017 May 4;7(1):1508. doi: 10.1038/s41598-017-01612-8.
Reconstructing the original biogeochemistry of organic fossils requires quantifying the extent of the chemical transformations that they underwent during burial-induced maturation processes. Here, we performed laboratory experiments on chemically different organic materials in order to simulate the thermal maturation processes that occur during diagenesis. Starting organic materials were microorganisms and organic aerosols. Scanning transmission X-ray microscopy (STXM) was used to collect X-ray absorption near edge spectroscopy (XANES) data of the organic residues. Results indicate that even after having been submitted to 250 °C and 250 bars for 100 days, the molecular signatures of microorganisms and aerosols remain different in terms of nitrogen-to-carbon atomic ratio and carbon and nitrogen speciation. These observations suggest that burial-induced thermal degradation processes may not completely obliterate the chemical and molecular signatures of organic molecules. In other words, the present study suggests that organic molecular heterogeneities can withstand diagenesis and be recognized in the fossil record.
重建有机化石的原始生物地球化学需要定量确定它们在埋藏诱导成熟过程中经历的化学转化程度。在这里，我们对化学性质不同的有机材料进行了实验室实验，以模拟成岩作用过程中发生的热成熟过程。起始有机材料为微生物和有机气溶胶。扫描透射 X 射线显微镜（STXM）用于采集有机残留物的 X 射线吸收近边光谱（XANES）数据。结果表明，即使在经受 250°C 和 250 巴的压力 100 天后，微生物和气溶胶的分子特征在氮与碳原子比以及碳和氮的形态方面仍然存在差异。这些观察结果表明，埋藏诱导的热降解过程可能不会完全抹去有机分子的化学和分子特征。换句话说，本研究表明，有机分子的异质性可以经受成岩作用，并在化石记录中被识别。
