报告题目：Investigation of Al³⁺and Fe³⁺substitution in bridgmanite by in-advanced high pressure technique in a large-volume press

报告人：刘兆东博士

Postdoc. Fellowship, Bayerisches Geoinstitut (BGI), University of Bayreuth, Germany

报告摘要：The pressure available of a typical large-volume press (LVP) is limited to 27 GPa due to the limitation of hardness of second-stage anvils of tungsten carbide (WC) anvils. Recent developments of high-pressure techniques using ultra-hard WC anvils can enable pressure reach up to 45 GPa under 2000 K. Especially, adapting sintered diamond (SD) anvils in the LVP can produce pressure up to 60 GPa under 2273 K, equivalent to intermediate regions (1500 km depth) of the lower mantle. These in-advanced high pressure techniquesin LVP can provide a relatively large specimen volume for precisely investigating sample’s physical and chemical properties under accurately controlled high-pressure and high-temperature conditions. Applying these high-pressure techniques in LVP, we conducted a series of HPHT experiments to clarify Al₂O₃and FeAlO₃incorporation into bridgmanite (MgSiO₃perovskite), the most abundant phase in the Earth’s lower mantle containing significant amounts of Fe and Al. We determined the pressure dependence of Al₂O₃solubilityin bridgmanite at pressures of 25-52 GPa and temperatures of 1700-2300 K, which provide good pressure references for LVP quench experiments at pressure above 30 GPa at various high temperatures. After that, we systematically investigate the effect of pressure and Al content on Al³⁺substitution mechanism in bridgmanite by electron probe microanalyzer(EPMA) and²⁷Al nuclear magnetic resonance to explain the geochemical storage such as water and argon in the lower mantle. Recently, we also studied the FeAlO₃incorporation in bridgmanite or LiNbO₃phase and synthesized large-size of 0.2-0.3 mm single crystals of FeAlO₃-bearing silicate LiNbO₃phase, which is converted from bridgmanite after decompression, to investigate its crystal chemistry using single crystal X-ray diffraction, EPMA, and Mössbauer spectra.

报告人简介：刘兆东博士，2009年本科毕业于山东潍坊学院物理系，2012年获得吉林大学凝聚态物理硕士学位，2015年在日本爱媛大学获得理学博士学位，2015年至今在德国拜罗伊特大学巴伐利亚州实验地球物理和化学研究所（BGI）做博士后研究。目前主要的研究领域包括：大压机的超高压技术的发展（采用超硬碳化钨和烧结金刚石作为二级顶硾)；超声波技术在大压机上的应用与发展；矿物的原位高温高压相变以及弹性性质研究；地幔矿物的物理和化学性质；大尺寸宝石级单晶和多晶矿物的合成和表征。目前在Geochem. Persp. Let., J. Geophys. Res., Phys. Earth Planet. Inter.等国际重要期刊发表论文多篇。

时间：2017年12月27日（周三）上午9:30

地点：前卫南区物理楼333讲学厅

举办单位：超硬材料国家重点实验室

物理学院

吉林省物理学会

中国物理学会高压物理专业委员会