Structure and thermal elastic properties of calcium silicate perovskite

硅酸钙钛矿的结构与热弹性性能

• 批准号: 2127807
• 负责人: Bin Chen
• 金额: $ 50万
• 依托单位: University of Hawaii
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2127807&HistoricalAwards=false
• 关键词: Structure; thermal; elastic; properties; calcium

Calcium silicate perovskite (CaPv) occurs as the third most abundant phase in the Earth’s lower mantle, next to (Mg,Fe)SiO3 bridgmanite and (Mg,Fe)O. It is considered a candidate mineral to explain some lower-mantle seismic observations and anomalies, as well as the main host for large cations in the lower mantle. Seismic properties of CaPv at mantle conditions, however, remain poorly constrained, as there are often contradictory theoretical and experimental predictions and determinations in the literature. Experiments and calculations have revealed multiple crystal structures of CaPv, but its phase transition boundary and elastic properties in the pressure-temperature-composition (P-T-X) space of relevance to the mantle are still under debate. This project will contribute to the following fundamental questions: (1) the fate of subducted oceanic crust and CaPv’s roles in lower mantle mineralogy and seismology, and (2) the origin of mantle’s seismic anomalies and heterogeneity. The project will directly contribute to the training of one graduate student at in-house laboratory and large synchrotron facilities and will also actively involve two early-career scientists. The research team will continue to mentor undergraduate students or high school students, particularly traditionally underrepresented minorities, i.e., Native Hawaiians and other Pacific Islanders, to study geosciences and planetary sciences by active involvement in ongoing research. The results from the proposed project will be disseminated via publications, national and international meetings, public lectures and news media.The proposed project aims to accurately measure the crystal structure and identify the phase transition boundary of (Al,Ti)-bearing CaSiO3 pervoskite in the P-T-X space of Earth’s mantle, employing laser-heated and externally-heated diamond anvil cell (EHDAC) and synchrotron X-ray diffraction techniques. The team will approach this goal by developing in-situ methods of growing non-quenchable silicate single crystals, and combining single-crystal/multigrain X-ray diffraction measurements with a newly developed EHDAC setups to reach temperatures above 1200 K. The proposed research aims to (1) determine the crystal structure and phase transformations of pure and (Ti,Al)-bearing CaPv, and (2) measure the thermal equation of state of CaPv at pressure-temperature conditions relevant to Earth's transition zone and lower mantle. The proposed measurements on the crystallographic phase transitions and thermal elastic properties of CaSiO3 will break open a bottleneck on the quest into the mantle mineralogy, and thus offer new understanding of CaPv’s contribution in elucidating the lower-mantle seismic observations and anomalies.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.

钙硅酮钙钛矿（CAPV）是地球下地幔中第三大相位，接近（mg，fe）sio3 bridgegmanite和（mg，fe）o。它被认为是候选矿物质，可以解释一些较低的地震观测和异常，也是低地幔中大阳离子的主要宿主。但是，CAPV在地幔条件下的地震特性仍然受到限制，因为文献中通常存在矛盾的理论和实验预测和确定。实验和计算揭示了CAPV的多个晶体结构，但其相变边界和与地幔相关的压力 - 温度组合（P-T-X）中的弹性特性仍在争议中。该项目将有助于以下基本问题：（1）俯冲的海洋壳和CAPV在低地幔Mineraology和Seomismology中的作用，以及（2）Mantle地震异常和异质性的起源。该项目将直接为内部实验室和大型同步器设施的一名研究生培训做出贡献，还将积极涉及两名早期职业科学家。研究团队将继续指导本科生或高中生，特别是传统上代表性不足的少数民族，即夏威夷原住民和其他太平洋岛民，通过积极参与正在进行的研究来研究地球科学和行星科学。拟议项目的结果将通过出版物，国际和国际会议，公开讲座和新闻媒体进行分散。拟议的项目旨在准确测量晶体结构并确定（Al，Ti）casio3 casio3 pervoskite的相过渡边界，在地球的p-t-x space中使用激光和外部的diamond and-externely-nemond-nevil-Heatron and villon and villron和diamond-eflon， X射线衍射技术。 The team will approach this goal by developing in-situ methods of growing non-quenchable silicone single crystals, and combining single-crystal/multigrain X-ray diffraction measurements with a newly developed EHDAC setups to reach temperatures above 1200 K. The proposed research aims to (1) determine the crystal structure and phase transformations of pure and (Ti,Al)-bearing CaPv, and (2) measure the thermal equivalence of state在压力温度条件下与地球的过渡区和下地幔相关的CAPV。提出的关于CASIO3的晶体学期过渡和热弹性特性的测量将打破对地幔Mineraology的追求的打开瓶颈，从而为CAPV对CAPV的贡献提供了新的理解，以阐明较低的地震观察和宣传NSF的智力范围，并阐明了NSF的范围，这是NSF的范围，并具有宽广的构建范围。审查标准。

项目成果

Experimental Constraints on the Fate of Subducted Sedimentary Nitrogen in the Reduced Mantle

还原地幔中俯冲沉积氮去向的实验约束

• DOI: 10.1029/2022jb025169
• 发表时间: 2022
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Huang, Shengxuan;Wu, Xiang;Chariton, Stella;Prakapenka, Vitali B.;Liang, Lin;Zhang, Dongzhou;Yang, Yan;Chen, Bin;Qin, Shan
• 通讯作者: Qin, Shan

Water‐Induced Diamond Formation at Earth's Core‐Mantle Boundary

地核-地幔边界处的水诱发钻石形成

• DOI: 10.1029/2022gl098271
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Ko, Byeongkwan;Chariton, Stella;Prakapenka, Vitali;Chen, Bin;Garnero, Edward J.;Li, Mingming;Shim, Sang‐Heon
• 通讯作者: Shim, Sang‐Heon