Collaborative Research: Experimental Study of Mineral-Fluid Fractionation of Non-Traditional Isotopes (Fe, Cu, Zn, S) with Implications for Seafloor Hydrothermal Systems

目前正在对海底热液喷口系统进行许多经验性研究，并正在进行越来越多的地球化学研究，以利用非常规稳定同位素（即，重元素如铁、锌、铜和硫）。为了允许这些经验研究的定量和预测结果，这些同位素的分馏因子必须是已知的。 然而，目前，没有实验工作，以获得这些系数和参数已进行。 这项研究建立了一个为期一年的概念验证研究，以表明分馏发生在这些系统中以系统的方式。新项目研究了温度，流体化学和反应速率对高温高压下硫化物矿物和流体之间非传统稳定同位素（Fe，Cu，Zn，S）分馏的影响。这项工作将包括相分离实验，以评估流体化学对蒸汽和盐水之间非传统稳定同位素分馏的作用。它将在平衡实验中使用同位素示踪剂来观察反应进程，并了解同位素系统学如何对反应速率和机制作出反应。硫同位素交换均匀和非均匀系统也将进行实验测试。这项工作的更广泛的影响包括通过发展动力学和分馏因素来建立科学的基础设施，这些因素对于预测含Fe，Cu，Zn和S的矿物稳定性的理论模型的发展至关重要。影响还包括研究生和本科生在国家的最先进的水岩相互作用的实验研究和早期职业PI从EPSCOR状态（路易斯安那州）的机构的参与。

Many empirical studies of hydrothermal vent systems on the seafloor and an increasing number of biogeochemical studies are being carried out to look at various mineralogical and biological processes using unconventional stable isotopes (i.e., those of heavy elements such as iron, zinc, copper, and sulfur). To allow quantitative and predictive results of these empirical studies, fractionation factors of these isotopes must be known. However, at present, no experimental work to derive these coefficients and parameters have been carried out. This research builds off a one-year proof-of-concept study to show that fractionation occurs in these systems in a systematic way. The new project examines the effects of temperature, fluid chemistry, and reaction rate on the fractionation of non-traditional stable isotopes (Fe, Cu, Zn, S) between sulfide minerals and fluids at elevated temperatures and pressures. The work will include phase separation experiments to assess the role of fluid chemistry on non-traditional stable isotope fractionation between vapor and brine. It will use isotope tracers in equilibrium experiments to look at reaction progress and to see how isotope systematics respond to reaction rates and mechanisms. Sulfur isotope exchange for homogeneous and heterogeneous systems will also be tested experimentally. Broader impacts of the work include building fundamental infrastructure for science via the development of kinetic and fractionation factors that are essential for the development of theoretical models for predicting stabilities of minerals containing Fe, Cu, Zn, and S. Impacts also include the engagement of graduate and undergraduate students in state-of-the-art experimental studies of water-rock interaction and the involvement of an early career PI from an institution in an EPSCOR State (Louisiana).