Hydrocarbons in Hydrothermal Vent Fluids: Mineral Catalyzed Metastability of Reduced Carbon Compounds at Elevated Temperatures and Pressures

摘要：Seyfried(0549457)：本研究利用新开发的热液流动反应器，对海底热液喷口高温高压下的碳还原反应机制和速率进行了研究。从大洋中脊的喷口喷出的热液为我们了解海水和海洋地壳的起源和演化提供了至关重要的线索。近年来，超镁铁质热液系统的喷口流体被发现含有丰富的、意想不到的溶解烃种类。实验允许将溶解气体（H2和CO2）和其他关键的含水物质加入到含有矿物反应物（催化剂）的反应池中，同时通过流出流体的有机化学变化来监测碳氢化合物形成的速率和过程。实验过程中溶解H2浓度和pH（酸度）。通过在单道和再循环模式下进行实验，有机污染可以最小化，而矿物表面的碳吸附可以最大化，便于通过高分辨率表面分析技术（XPS， TOF-SIMS和C-XANES）对矿物表面进行分析。矿物催化剂将包括广泛的氧化物、硫化物和硅酸盐，这些氧化物、硫化物和硅酸盐是超镁铁质热液系统海底反应带的典型特征，这是从这些系统的喷口流体化学中推断出来的。这项工作的更广泛影响包括通过UM/NSF REU流体在地球上的研究参与本科生。该项目为来自传统本科院校的优秀学生提供支持，让他们参与实验设计和分析来自拟议调查的运行产品。它还将涉及开发具有原位化学传感器的拟议热液流动反应器。

ABSTRACT: Seyfried (0549457)Intellectual Merit: This research constrains the mechanism and rate of carbon reduction reactions that abiotically create hydrocarbons in ultramafic seafloor hydrothermal systems using a newly developed hydrothermal flow-through reactor that can measure reactions at the high temperatures and pressures present at hydrothermal vents in the seafloor. Hydrothermal fluids issuing from vents at mid-ocean ridges provide clues critical to our understanding of the origin and evolution of seawater and the oceanic crust through time. Recently, vent fluids from ultramafic-hosted hydrothermal systems have been found to contain abundant and largely unexpected dissolved hydrocarbon species. The experiments allow dissolved gases (H2 and CO2) and other key aqueous species to be added to a reaction cell that contains mineral reactants (catalysts), while rates and processes of hydrocarbon formation are monitored simultaneously from changes in the organic chemistry of the out-flow fluid. Dissolved H2 concentrations and pH (acidity) during the experiments. By performing experiments in both single pass and recirculation modes, organic contamination can be minimized, while carbon adsorption on mineral surfaces can be maximized, facilitating analysis of mineral surfaces by high-resolution surface analytical techniques (XPS, TOF-SIMS, and C-XANES). Mineral catalysts will include a wide range of oxides, sulfides and silicates typical of subseafloor reaction zones in ultramafic-hosted hydrothermal systems, as inferred from reported vent fluid chemistry from these systems. Broader impacts of the work include involvement of undergraduate students in research through the UM/NSF REU Fluids in the Earth. This program provides support for high achieving students from traditionally undergraduate institutions to join in the experimental design and analysis of run products derived from of the proposed investigation. It will also involve development of the proposed hydrothermal flow reactor with in-situ chemical sensors.