Collaborative Research: CSEDI: Understanding the Role of Hydrogen and Melting in the Water Transport Across the Transition Zone-Lower Mantle Boundary

合作研究：CSEDI：了解氢和熔化在跨过渡带-下地幔边界的水传输中的作用

• 批准号: 2001381
• 负责人: Jung-Fu Lin
• 金额: $ 24.1万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-15 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2001381&HistoricalAwards=false
• 关键词: Collaborative; Research; CSEDI; Understanding; Role; Collaborative; Research; CSEDI; Understanding; Role

The aim of this project is to conduct new experimental and theoretical studies on the properties of mineral in the deep interior of Earth that will help us to understand the nature of global water circulation in Earth’s mantle. Not only on the surface, water (hydrogen) is present inside of Earth and slowly circulates. This global water circulation creates and maintains oceans on Earth. Based on a number of studies during the last a few decades, there is a clear idea about the water circulation in the shallow part of Earth’s interior. However, the nature of water circulation in the largest part of the mantle, the lower mantle, remains poorly constrained. A key in the global water circulation is the role of melting. Melting removes water from minerals to melt, and melt migrates a long distance to cause large-scale water transport. However, the nature of global water circulation in the deep mantle is very poorly understood mainly because our understanding of water in the minerals in the deep mantle is limited. The PI team will bring together a suite of theoretical and experimental methods to address these questions, and will train both graduate and undergraduate students at three institutions on a cross-cutting research project. The PIs will also engage in public outreach events.In this new project, the water solubility in bridgmanite (dominant lower mantle mineral) will be determined under the shallow lower mantle conditions from ~660 km to ~1000 km depth, and also the role of water (hydrogen) on electrical conductivity in bridgmanite will be investigated. Experimental studies will be made on clean single crystals of bridgmanite and the hydrogen content and solubility mechanisms will be studied using FTIR and SIMS. Electrical conductivity will be measured on these samples for different orientations using the AC impedance spectroscopy. First-principle computational studies will also be made on hydrogen solubility and mobility in bridgmanite to help interpreting the experimental results. These results will help us to develop a model of global water circulation and to test models against geophysical estimates of water distribution.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.

该项目的目的是对地球深层内部矿物质的特性进行新的实验和理论研究，这将有助于我们了解地球地幔中全球水流通的性质。不仅在地面上，水（氢）也存在于地球内部并缓慢循环。这种全球水循环在地球上创造并维持海洋。根据过去几十年来的许多研究，关于地球内部浅层部分的水循环有一个清晰的想法。然而，地幔最大部分的水循环性质仍然受到限制。全球水循环的关键是融化的作用。熔化可去除从矿物质到融化的水，并融化很长的距离，以引起大规模的水运输。然而，深地幔中全球水循环的性质非常鲜为人知，主要是因为我们对深层矿物质中水的理解受到限制。 PI团队将汇集一套理论和实验方法来解决这些问题，并将在三个机构的跨切割研究项目中培训三个机构的研究生和本科生。 PIS还将参加公共外展活动。在这个新项目中，将在浅层下层壁画条件下确定Bridgemanite（主要的下篮子矿物）的水溶解度，从〜660 km到〜1000 km的深度，还将研究水（氢）在Bridgemanite中的作用（氢）。将对Bridgemanite的清洁单晶进行实验研究，并将使用FTIR和SIMS研究氢含量和可溶机制。使用交流阻抗光谱法上将在这些样品上测量电导率。还将对Bridgemanite中的氢气和迁移率进行第一本计算研究，以帮助解释实验结果。这些结果将有助于我们开发全球水流通模型，并测试对水分配的地球物理估计的测试模型。该奖项反映了NSF的法定任务，并使用基金会的知识分子优点和更广泛的影响审查标准，通过评估被认为是珍贵的支持。