Pathways for the Abiotic Formation of Organic Compounds in Geologic Environments

McCollomEAR-0229837这项工作是关于在地质环境中合成非生物有机化合物的反应的实验研究。虽然地质样品中常见的非生物碳氢化合物表明，它们的形成在整个地球历史上都很普遍，但这些化合物形成的环境仍然知之甚少。这项研究将采用几种实验方法来检查二氧化碳还原形成有机化合物的反应路径，并确定允许这些反应进行的地质条件。特别是，这些实验将涉及：(I)水相与气相反应在非生物有机合成中的作用，(Ii)富橄榄石岩石的水热蚀变(蛇纹岩化)期间非生物碳氢化合物的生成，以及(Iii)含铁碳酸盐的热分解过程中石墨和有机物的形成。这些结果将加深我们对火成岩、热液、蛇纹岩和陨石等地质样品中非生物有机化合物来源的理解。这些信息将有助于限制非生物碳氢化合物流量的大小及其在全球碳循环中的潜在作用。这些结果还将有助于理解非生物来源对地球早期岩石样品中发现的还原碳的贡献，并有助于确定生命起源和早期演化的益生有机化合物的来源。

McCollomEAR- 0229837This work is an experimental investigation of reactions that synthesize abiotic organic compounds in geologic environments. Although the common occurrence of abiotic hydrocarbons in geologic samples indicates that their formation has been widespread throughout the history of the Earth, the circumstances under which these compounds form remain poorly understood. The study will employ several experimental approaches to examine reaction pathways for the formation of organic compounds from reduction of CO2, and define the geologic conditions that allow these reactions to proceed. In particular, the experiments will address: (i) the role of aqueous phase versus vapor phase reactions in abiotic organic synthesis, (ii) the generation of abiotic hydrocarbons during hydrothermal alteration of olivine-rich rocks (serpentinization), and (iii) formation of graphite and organic matter during thermal decomposition of iron-bearing carbonates. The results will enhance our understanding of the origin of abiotic organic compounds in geologic samples such as igneous rocks, hydrothermal fluids, serpentinites, and meteorites. This information will be useful in constraining the magnitude of the flux of abiotic hydrocarbons and their potential role in global carbon cycles. The results will also be useful in understanding the contribution of abiotic sources to the reduced carbon found in rock samples from the early Earth, and in defining sources of prebiotic organic compounds for the origin and early evolution of life.