CAREER: Partitioning of Rare Earth Elements (REE) Between Minerals and Aqueous Fluids in Ore Deposits

职业：矿床中的矿物和水流体之间的稀土元素 (REE) 分配

• 批准号: 1845258
• 负责人: Alexander Gysi
• 金额: $ 57.75万
• 依托单位: Colorado School of Mines
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-07-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1845258&HistoricalAwards=false
• 关键词: CAREER; Partitioning; Rare; Earth; Elements; CAREER; Partitioning; Rare; Earth; Elements

The rare earth elements (REE) have similar but slightly different ionic radii and atomic masses, which permits studying the fundamental behavior of chemical elements and their incorporation in mineral structures in natural systems. Their magnetic properties make them important components in permanent magnets used in wind turbines, batteries of hybrid cars, and phosphors in energy efficient light. The REE composition of minerals is also used in geosciences to trace geological processes in the Earth's crust. Ore deposits commonly form at depth through the mobilization of metals in aqueous fluids and the mineralization in hydrothermal veins. The properties of both, the fluid and the minerals, will affect how the different REE are fractionated. Currently, we have much to discover about how to quantify systematically the trace element signatures of minerals with regards to fluid-rock interaction and ore-forming processes. This CAREER proposal explores how REE fractionate between aqueous fluids and minerals in ore deposits using laboratory experiments, numerical modeling and fluid inclusions trapped in natural minerals. The THERMO fluids project will be initiated with the preparation of a Fluids & Minerals summer school for undergraduate students, an open access booklet, and a dedicated hands-on thermodynamics tutorial webpage. A major aim of this project will be to provide an education platform and demonstrate the broader significance of thermodynamics in geosciences. Calcite, fluorite and apatite are common gangue minerals associated to REE and other mineral deposits. These minerals record geochemical signatures that may be used to determine temperature, fluid chemistry and potentially fluid pathways associated to ore-forming processes. This research involves a comprehensive series of hydrothermal experiments at 100 to 350 degrees C for determining the partitioning of REE between aqueous fluid-calcite, -apatite and -fluorite as a function of temperature and fluid composition (i.e., salinity, pH and ligand activity). The experimental data will be used to develop a new thermodynamic model for predicting and quantifying REE signatures in these hydrothermal minerals. To test the model, a set of mineral trace element compositions and fluid inclusions will be studied in peralkaline, carbonatite, and iron oxide-apatite hosted ore deposits in North America. The objective of the proposed research is to provide a framework for simulating the partitioning of trace metals associated to fluid-rock reactions in ore deposits and advance our capabilities of modeling and interpreting ore-forming processes.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

稀土元素（REE）具有相似但略有不同的离子半径和原子质量，该质量允许研究化学元素的基本行为及其在自然系统中的矿物结构中的基本行为。它们的磁性使它们在风力涡轮机，混合动力汽车的电池和能节能光中使用的永久磁铁中的重要组成部分。矿物质的REE组成也用于地球科学中，以追踪地质的地壳中的地质过程。矿石沉积通常是通过在水性流体中的金属和水热静脉中的矿化化而在深度形成的。流体和矿物质的性质都将影响不同的REE分馏的方式。目前，关于如何系统地量化矿物质的痕量元素特征，关于流体岩石相互作用和形成矿石的过程，我们有很多要发现的。该职业建议探讨了如何使用实验室实验，数值建模和被困在天然矿物质中的矿石沉积物中的水性液体和矿物质之间的分数。 Thermo Fluids项目将通过为本科生的液体和矿产暑期学校的准备，开放式访问手册以及专门的动手热力学教程网页。该项目的主要目的是提供一个教育平台，并证明热力学在地球科学中的广泛意义。方解石，氟石和磷灰石是与REE和其他矿物沉积有关的常见脉矿矿物。这些矿物质记录了可用于确定温度，流体化学和可能与矿石形成过程相关的流体途径的地球化学特征。这项研究涉及在100至350摄氏度下进行一系列全面的热液实验，以确定REE在水性流体 - 钙岩，-Apatite和-fluorite之间的分配，这是温度和液体组成的函数（即盐度，pH和配体活动）。实验数据将用于开发一种新的热力学模型，用于预测和量化这些热液矿物质中的REE特征。为了测试该模型，将研究一组矿物质元素组成和流体夹杂物，在北美的甲基盐，碳酸盐和氧化铁 - 氧化铁托管宿主沉积物中。拟议的研究的目的是提供一个框架，以模拟与矿床中与流体摇滚反应相关的痕量金属分配，并提高我们建模和解释矿石形成过程的能力。该奖项反映了NSF的法定任务，并通过使用基金会的知识优点和广泛的效果来评估NSF的法定任务，并通过评估值得进行评估。