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

使用成对的喷口流体和固体量化微量元素在海底热液矿床中的分配

• 批准号: 1536480
• 负责人: Margaret Tivey
• 金额: $ 18.9万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1536480&HistoricalAwards=false
• 关键词: Quantifying; Partitioning; Trace; Elements; into

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.

热液喷口是海底硫化物矿床的重要来源，但对微量元素如何进入热流体及其相应的硫化物烟囱的过程知之甚少。该项目将测量一个天然热液喷口系统的流体-烟囱对中的微量元素浓度。 该项目的数据将提高我们对微量元素如何在流体和相应矿物之间过渡的理解，并将其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形成和金属再活化的建模研究。该项目将支持对本科生和研究生的培训，并将通过制作教育录像广泛分享成果，过去，由于喷口流体和固体的浓度很低，缺乏微量元素数据，因此，利用喷口流体和相应的烟囱衬里来检验分隔假设一直受到阻碍。最近的努力，使用改进的分析技术，使调查微量元素分区。该项目将利用一个天然热液喷口系统，调查微量元素从流体中分离成硫化物矿物的情况，硫化物矿物在实验室难以重现的条件下，沿着与热喷口流体接触的烟囱管道衬里沉淀下来。将对一组流体-烟囱对（同时对流体和烟囱取样）进行分析。本项目的数据和分析将用于检验以下两个假设：1）从喷口流体中沿烟囱沿着沉淀的矿物以特有的方式掺入某些微量元素，分配主要是元素浓度的函数，pH值、温度、氧化还原和配体浓度影响游离浓度和总浓度; 2）海底硫化物矿床记录了关于形成这些矿床的流体的微量元素组成以及关于沉淀时的环境条件的重要信息;因此，痕量元素分布可用作环境条件如pH、氧化还原、温度和/或金属浓度的代表。