Biomaker and Carbon Isotope Geochemistry of Pyrolytic and Chemosynthetic Processes in Sedimented Hydrothermal Systems

这是一项与生物学家持续合作的研究工作，主要是在瓜伊马斯盆地，随后对东北太平洋（中部山谷，胡安·德·富卡和戈尔达山脊），非洲裂谷（坦噶尼喀湖）和大陆下的热点（黄石公园）的物质进行研究。由热液循环带到海底的有机质（石油）代表了深层有机碎屑快速生成的热解产物，是血液合成食物网的碳源。这种类型的碳循环及其地质命运将在热液沉积裂谷系统中进行研究。活跃，主要接收陆生有机碎屑（Escanaba海槽）。这将通过结合有机和同位素地球化学来研究沉积后有机质（石油）热解蚀变、生物降解/风化过程和化学合成碳固定之间的相互关系。还将研究温度约束下的化学反应（如芳构化、脱水、异构化），以确定不同化合物类别的形成“窗口”。这些化合物类的环境命运将被检查，以评估溶解度，氧化风化和生物降解。关键的反应和过程将在实验室中通过加水热解实验进行模拟。不同有机质组分的碳14定年将限制碳质物质蚀变的来源和底下深度。因此，分子和同位素特征将能够用于追踪碳从这些热液环境的来源转移。

This is a continuing and collaborative research effort with biologists on the hydrothermal emanations, primarily in Guaymas Basin, with follow up studies on material from the Northeastern Pacific (Middle Valley, Juan de Fuca and Gorda Ridges), African Rift Valley (Lake Tanganyika), and a hot spot under a continent (Yellowstone Park). The organic matter (petroleum) brought to the seabed by hydrothermal circulation represents the rapidly generated pyrolytic products from organic detritus at depth and is a carbon source for the hemosynthetic food web. This type of carbon cycling and its geological fate will be studied in a sedimented rift system which is hydrothermally.active, receiving primarily terrestrial organic detritus (Escanaba Trough). This will be done by coupling organic and isotope geochemistry to examine interrelationships between post.depositional pyrolytic alteration of organic matter (petroleum), biodegradation/weathering processes and chemosynthetic carbon fixation. Chemical reactions (e.g. aromatization, dehydration, isomerization) with temperature constraints also will be studied to define formation "windows" for different compound classes. The environmental fate of these compound classes will be examined to assess solubility, oxidative weathering and biodegradation. Key reactions and processes will be simulated in the laboratory by hydrous pyrolysis experiments. Carbon.14 dating of different organic matter fractions will place constraints on the sources and subbottom depths of the alteration of carbonaceous materials. Thus, molecular and isotopic signatures will be able to be used to trace the transfer of carbon from sources through these hydrothermal environments.