Testing the geological fate of abiogenic carbonaceous matter

有机质（OM）作为前寒武纪岩石中潜在的生物标志物一直是众多研究的焦点。然而有机质本身不能作为生命存在的证据，因为有机质存在着大量的非生物来源，如陨石的搬运和非生物有机合成。后者可能是由热液能量、撞击、闪电或紫外线辐射推动的，可能在早期地球上进行的程度比今天大得多。在拟议的项目中，P，T-实验将进行调查的非生物OM的费托合成（FTT）型（FTT）的热演化。目的是为前寒武纪岩石和其他地质样品中生物和非生物有机质的区分提供线索。FTT合成将在水热条件下使用Morey型反应容器和蒙脱石粘土作为催化剂进行。将所得的非生物有机质在冷密封压力容器（CSPV，金袋）中在岩石静压力（1，5 kbar）下人工成熟10个不同的时间间隔（10分钟-1年）。由未成熟的始新世油页岩制备的I型油母质平行运行作为参考。采用GC-MS、GC-C-IRMS、催化加氢热解（HyPy）和拉曼光谱分析FTT衍生的OM及其成熟产物（沥青和干酪根）。然后将在不同P，T条件下成熟的非生物OM的性质与真实世界的非生物物质进行比较。我们希望，这些结果将为我们提供一个强大的线索，保存在不同相的最古老的陆地岩石携带土著有机质的个别干酪根的生物成因。

Organic matter (OM) has been in the focus of numerous investigations as a potential biosignature in Precambrian rocks. However OM can not per se been taken as evidence of life, because there existed numerous abiogenic sources, such as delivery from meteorites and abiogenic organic synthesis. The latter, possibly fueled by hydrothermal energy, impacts, lightning, or UV-radiation, may have proceeded to a much greater extent on the early Earth than today. In the proposed project, a P,T-experiment will be performed to investigate the thermal evolution of abiotic OM generated by Fischer-Tropsch type (FTT) synthesis. The goal is to provide clues to the distinction of biogenic and abiotic OM in Precambrian rocks and other geological samples. FTT synthesis will be performed under hydrothermal conditions using Morey-type reaction vessels and montmorillonite clay as a catalyst. The resulting abiotic OM are artificially maturated in cold-seal pressure vessels (CSPV, gold bags) at lithostatic pressure (1,5kbar) for 10 different time intervals (10min-1yr). Type I kerogen prepared from an immature Eocene oil shale is run in parallel as a reference. The FTT-derived OM and its maturation products (bitumen and kerogen) are analysed using GC-MS, GC-C-IRMS, catalytic hydropyrolysis (HyPy), and Raman-spectroscopy. The properties of abiotic OM maturated under different P,T-conditions will then be compared to Archaean real-world materials. We expect that the results will provide us with a robust clues to the biogenicity of individual kerogens preserved in different facies of the oldest terrestrial rocks carrying indigenous OM.