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

这是与生物学家就热液喷发进行的持续和合作的研究工作，主要是在瓜伊马斯盆地，并对东北太平洋(中谷、胡安德富卡和戈尔达海脊)、非洲裂谷(坦噶尼喀湖)和大陆下的一个热点(黄石公园)的物质进行后续研究。水热循环带到海底的有机物质(石油)代表着深层有机碎屑迅速产生的热解产物，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一个沉积的裂谷系统中进行研究，该系统是热液活动的，主要接收陆地有机碎屑(埃斯卡纳巴海槽)。这将通过有机和同位素地球化学相结合的方法来研究有机质(石油)沉积后热解蚀变、生物降解/风化过程和化学合成固碳之间的相互关系。还将研究有温度限制的化学反应(如芳构化、脱水、异构化)，以确定不同化合物类别的形成窗口。将检查这些化合物类别的环境命运，以评估溶解性、氧化风化和生物降解。关键反应和过程将在实验室通过水合热解实验进行模拟。碳14不同有机质组分的测年将对碳质物质蚀变的来源和海底深度造成限制。因此，分子和同位素特征将能够用来追踪碳通过这些热液环境从源头转移的过程。

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.