Quantifying Partitioning of Trace Elements into Seafloor Hydrothermal Deposits Using Paired Vent Fluids and Solids

热液喷口是海底硫化物矿藏的重要来源，但对微量元素如何融入热流体及其相应的硫化物烟囱的过程知之甚少。该项目将测量来自天然热液喷口系统的流体-烟囱对中的微量元素浓度。该项目的数据将增进我们对微量元素如何在流体和相应矿物之间转化的理解，并将被纳入旨在量化从热液喷口到深海的微量元素通量的研究，以及侧重于块状硫化物的形成和金属再动员的模拟研究。该项目将支持本科生和研究生的培训，并将通过制作教育视频广泛分享结果。过去，由于浓度非常低，缺乏喷口流体和固体的痕量元素数据，使用喷口流体和相应的烟囱衬里来测试分隔假说一直受到阻碍。最近利用改进的分析技术所做的努力使对微量元素分配的研究成为可能。该项目将使用天然热液喷口系统来研究微量元素从流体中分配到硫化物矿物中的情况，这些矿物在实验室难以再现的条件下，沿着烟囱管道的衬里沉淀，与热的喷口流体接触。将对一组流体-烟囱对(流体和烟囱同时采样)进行分析。将利用这个项目的数据和分析来检验下列两个假设：1)沿烟囱衬里的喷口流体中沉淀的矿物以一种特有的方式结合了一些微量元素，其分配主要是元素浓度的函数，并随pH、温度、氧化还原和配体浓度的变化而影响自由浓度和总浓度；2)海底硫化物沉积物记录了有关形成它们的流体的微量元素组成和降水时环境条件的关键信息；因此，痕量元素分布可用作环境条件，如pH、氧化还原、温度和/或金属浓度的替代。

Hydrothermal vents are an important source of sulfide mineral deposits to the ocean floor, but the processes of how trace elements get incorporated into the hot fluids and their corresponding sulfide chimneys is poorly understood. This project will measure trace element concentrations in fluid-chimney pairs from a natural hydrothermal vent system. The data from this project will enhance our understanding of how trace elements transition between the fluid and corresponding mineral, as well as be included into studies that aim to quantify trace element fluxes from hydrothermal vents to the deep ocean and modeling studies focused on formation of massive sulfides and metal remobilization. This project will support the training of undergraduate and graduate students, and results will be shared broadly through the creation of educational videos.Use of vent fluids and corresponding chimney linings to test hypotheses of partitioning has been hampered in the past by a lack of trace element data for both vent fluids and solids due to the very low concentrations. Recent efforts using improved analytical techniques now make investigations of trace element partitioning possible. This project will use a natural hydrothermal vent system to investigate trace element partitioning from fluids into sulfide minerals that precipitate along the linings of the chimney conduits, in contact with the hot vent fluids, at conditions difficult to reproduce in the laboratory. Analyses will be done on a set of fluid-chimney pairs (fluid and chimney sampled at the same time). Data and analyses from this project will be used to test the following two hypotheses: 1) Minerals precipitating from vent fluids along linings of chimneys incorporate some trace elements in a characteristic manner, with partitioning dominantly a function of element concentrations, and with pH, temperature, redox, and ligand concentration affecting free versus total concentrations; and 2) Seafloor sulfide deposits record critical information about both the trace element compositions of the fluids from which they formed, and about environmental conditions at the time of precipitation; thus, trace element distributions could be used as proxies for environmental conditions such as pH, redox, temperature, and/or metal concentrations.