Controls on the Abundance of Carbon Species in Unsedimented Submarine Hydrothermal Systems: An Experimental Investigation

随着对大洋地壳热液沃茨大规模排放和循环的范围和性质的更多发现，从地下地球化学循环中描绘非生物化学在某些意义上变得越来越模糊，但在另一些意义上却明显地交织在一起。考虑有机化合物在水热流体的化学目前提出了许多不确定性和有趣的问题。本研究的刻意限制实验室实验方法将使用灵活的热液容器来研究一些关键的化学目标：i）在适合于大洋玄武岩热液蚀变期间经历的条件的温度和压力下测量方解石溶解度，ii）测定矿物催化的CO2非生物还原为CH4的速率，和iii）评价水的热力学活性对催化活性矿物对还原碳化合物的非生物形成的有效性的影响。对这些研究结果的解释这些研究对海洋中脊碳循环、过量二氧化碳的地质固存、极端环境中生命的存在甚至其起源等看似多种多样的主题产生了影响。

ABSTRACTOCE-0136954As more is discovered of the extent and nature of the large scale venting and circulation of hydrothermal waters through the oceanic crust, delineation of abiotic chemistries from subsurface biogeochemical cycles has become increasingly blurred in some senses, yet clearly intertwined in others. Consideration of the chemistry of organic compounds in aqueous hydrothermal fluids currently poses many uncertainties and intriguing questions. The deliberately constrained laboratory experimental approach of this study will use flexible-cell hydrothermal vessels to investigate a number of key chemical objectives: i) measurement of calcite solubility at temperatures and pressures appropriate to the conditions experienced during the hydrothermal alteration of oceanic basalts, ii) determination the mineral catalyzed rates of abiotic reduction of CO2 to CH4 and iii) evaluation of the influence of the thermodynamic activity of water on the effectiveness of catalytically active minerals on the abiotic formation of reduced carbon compounds.Interpretation of the results of these investigations has impact upon topics as seemingly diverse as the mid-ocean ridge carbon cycle, the geological sequestration of excess carbon dioxide, the existence of life in extreme environments and even its origin.