Collaborative Research: Serpentinization and cycling of B, Nd and Sr in submarine hydrothermal systems: An experimental study on the effects of pH and temperature

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。热液蚀变洋壳记录了大洋中脊和俯冲带在热液循环期间海水与地幔之间的热量和质量转移。产生蛇纹石矿物的热液喷口系统与富含有机物的碱性流体相连，是为海底微生物生命提供能源的中心。这项研究使用硼、锶和钕元素浓度以及硼同位素分馏来考察水-岩反应在橄榄岩和其他常见于海底和下地壳的超镁铁质岩石转化为蛇纹石和其他矿物中的作用。这项工作涉及新颖的受控热液实验室实验，研究了pH、温度和矿物组成对硼同位素分馏的控制以及B-Sr-ND组合的迁移性和岩石-流体交换。之所以选择有针对性的地球化学元素，是因为它们是温度和流体pH条件的记录器，并允许将实验结果应用于化石热液系统和相关矿床。此外，这些测量将限制低温蛇纹岩作用对跨越火山弧的元素循环效率的影响，并加强我们对俯冲板块影响岛弧火山岩的地球化学通量的了解。这项工作的更广泛影响是支持两名早期职业研究人员，促进新的合作，支持学生，国际合作，以及支持处于EPSCoR状态的机构。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).Hydrothermally altered ocean crust provides a record of heat and mass transfer between seawater and the earth's mantle that takes place during hydrothermal circulation at mid ocean ridges and subduction zones. Hydrothermal vent systems that generate the mineral serpentine are linked to alkaline fluids enriched in organics and are central to generating the energy supply for microbial life at the seafloor. This research uses boron, strontium, and neodymium elemental concentrations as well as boron isotope fractionation to examine the role of water-rock reaction in the conversion of peridotites and other ultramafic rocks common on the seafloor and in the lower crust to serpentine and other minerals. The work involves novel, controlled, hydrothermal, laboratory experiments that examine the pH, temperature and mineral composition controls on boron isotope fractionation and combined B-Sr-Nd mobility and rock-fluid exchange. Targeted geochemical elements were picked because they are recorders of temperature and fluid pH conditions and allow application of the results of the experiments to fossil hydrothermal systems and associated ore deposits. Furthermore, the measurements will constrain the effects of low-temperature serpentinization on the efficiency of elemental recycling across volcanic arcs and enhance our understanding of geochemical fluxes from subducting slabs which impact island arc volcanics. Broader impacts of the work are support of two early career researchers, promotion of a new collaboration, support of students, international collaboration, and support of an institution in an EPSCoR state.