Study of water solubility in bridgmanite at the lower mantle conditions

下地幔条件下桥锰矿的水溶性研究

• 批准号: 1723185
• 负责人: Jiuhua Chen
• 金额: $ 36万
• 依托单位: Florida International University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-15 至 2022-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1723185&HistoricalAwards=false
• 关键词: Study; water; solubility; bridgmanite; lower

Nearly all minerals can take at least small amount of water in their structure although the capability of water uptake varies from mineral to mineral. Due to the huge mass of mantle dominant minerals, even very small solubility of water in the minerals may produce a massive water reservoir in Earth's interior. For example, 2-3 weight % solubility of water in the transition zone major minerals (wadsleyite and ringwoodite) results in a capability of water storage in this part of Earth's interior equivalent to two and a half total oceans on Earth's surface. Knowledge about the water solubility in difference minerals helps people understand fate of water brought into Earth's interior by subduction processes, deep water cycling and its influence on seismic wave propagation in the corresponding area. While water solubility in the upper mantle and transition zone minerals are well investigated, related studies on the lower mantle dominant mineral, bridgmanite, especially the influence of pressure and water fugacity, are very limited. This project will systematically study the capacity for water uptake in the bridgmanite crystal structure as a function of pressure and water fugacity. The research activities will be carried out mainly at Florida International University, a Minority Serving Institution (MSI) and the largest Hispanic Serving Institution (HSI) in mainland US. Progress of the research will be introduced to the undergraduate and graduate students through classes taught by the PI under the topic of how many oceans are there inside the Earth to draw the interest in science, technology, engineering, and mathematics (STEM) among students of underrepresented minorities. Such a natural connection has been proved very effective for the PI to attract students to become involved in Research Experiences for Undergraduates and/or Independent Research.The project will determine the parameters in the general formula in water concentration calculation for bridgmanite. The samples will be synthesized from a mixture of oxides and hydroxide (SiO2, MgO, FeO, Al2O3 and Mg(OH)2) with saturated water content. A multi-anvil press with hard tungsten carbide and sintered diamond anvils will be used to produce samples with large crystal size for water concentration characterizations. Both Fourier transform infrared spectroscopy (FTIR) and secondary ion mass spectrometry (SIMS) will be used for determining the water contents in the synthesized specimens, minimizing the uncertainty due to possible inclusions of H2O fluid or hydroxyl bearing phases. The project will characterize the water storage capability in the deep mantle, provide critical mineral physics data for geodynamic modeling, and therefore advance our knowledge and understanding in geophysics and geochemistry of Earth's deep interior. The project takes the advantage of new developments in the multi-anvil apparatus to reach pressures far higher than that at the top of the lower mantle using sintered diamond anvils. The larger sample size with respect to diamond anvil cell (DAC) experiments will ensure the quality of analytical characterization of water concentration in the recovered specimens. Comparative analyses using FTIR and SMIS will help for distinguishing the structural bound hydroxyls from molecular water in crystal inclusions.

几乎所有的矿物都可以在其结构中至少吸收少量的水，尽管不同的矿物吸收水分的能力不同。由于地幔中占主导地位的矿物质量巨大，即使是极小的水在矿物中的溶解度也可能在地球内部产生巨大的储水层。例如，过渡带主要矿物(瓦兹利石和环木石)中2-3重量%的水的溶解度导致地球内部这一部分的储水能力相当于地球表面上两个半海洋的总量。对不同矿物中水的溶解度的了解有助于人们了解通过俯冲过程进入地球内部的水的去向、深水循环及其对相应地区地震波传播的影响。虽然上地幔矿物和过渡带矿物中的水的溶解度得到了很好的研究，但对下地幔中的优势矿物--桥辉橄榄石，特别是压力和水逸度的影响的研究却非常有限。本项目将系统地研究水镁锰矿晶体结构中的吸水能力随压力和水逸度的变化。研究活动将主要在佛罗里达国际大学、少数族裔服务机构(MSI)和美国本土最大的拉美裔服务机构(HSI)进行。这项研究的进展将通过PI讲授的课程向本科生和研究生介绍，主题是地球内部有多少海洋，以吸引未被充分代表的少数族裔的学生对科学、技术、工程和数学(STEM)的兴趣。这种天然的联系已被证明是非常有效的PI吸引学生参与本科生的研究经验和/或独立研究。该项目将确定水镁石水分浓度计算的通用公式中的参数。样品将由饱和水分含量的氧化物和氢氧化物(二氧化硅、氧化镁、氧化铁、三氧化二铝和氢氧化镁)的混合物合成。采用硬质碳化钨和烧结金刚石顶锤的多锤头压力机将用于生产用于水浓度表征的大晶体尺寸的样品。傅里叶变换红外光谱(FTIR)和二次离子质谱仪(SIMS)都将用于测定合成样品中的水分含量，最大限度地减少由于可能包含H2O流体或含羟基相的不确定度。该项目将表征深部地幔的储水能力，为地球动力学模拟提供关键的矿物物理数据，从而增进我们对地球深部地球物理和地球化学的认识和理解。该项目利用了多砧座设备的新发展，以达到远高于使用烧结钻石砧座的下地幔顶部的压力。钻石砧座(DAC)实验的较大样本量将确保回收样品中水浓度的分析表征的质量。FTIR和SMIS的对比分析将有助于区分晶体包裹体中的结构结合羟基和分子水。

项目成果

Synthesis of nanopolycrystalline mesoporous diamond from periodic mesoporous carbon: Mesoporosity increases with increasing synthesis pressure

• DOI: 10.1016/j.scriptamat.2018.10.024
• 发表时间: 2019-03
• 期刊: Scripta Materialia
• 影响因子: 6
• 作者: Shah Najiba;Stephen J. Juhl;Manik Mandal;Cong Liu;A. Durygin;Jiuhua Chen;Y. Fei;N. Alem;K. Landskron

Study on the High-Pressure Behavior of Goethite up to 32 GPa Using X-Ray Diffraction, Raman, and Electrical Impedance Spectroscopy

• DOI: 10.3390/min10020099
• 发表时间: 2020-01
• 期刊: Minerals
• 影响因子: 2.5
• 作者: Ruilian Tang;Jiuhua Chen;Q. Zeng;Yan Li;Xue Liang;Bin Yang;Yu Wang

Is Earth’s Core Rusting?

地球核心生锈了吗？

• DOI: 10.1029/2022eo220201
• 发表时间: 2022
• 期刊: Eos
• 作者: Chen, Jiuhua;Esdaille, Shanece
• 通讯作者: Esdaille, Shanece

Probing the Electronic Band Gap of Solid Hydrogen by Inelastic X-Ray Scattering up to 90 GPa

通过高达 90 GPa 的非弹性 X 射线散射探测固体氢的电子带隙

• DOI: 10.1103/physrevlett.126.036402
• 发表时间: 2021
• 期刊: Physical Review Letters
• 影响因子: 8.6
• 作者: Li, Bing;Ding, Yang;Kim, Duck Young;Wang, Lin;Weng, Tsu-Chien;Yang, Wenge;Yu, Zhenhai;Ji, Cheng;Wang, Junyue;Shu, Jinfu
• 通讯作者: Shu, Jinfu