High-pressure-temperature phase relations of basaltic crust under lower-mantle conditions: implications for chemical heterogeneity in the lower mantle

下地幔条件下玄武岩地壳的高压-温度相关系：对下地幔化学不均匀性的影响

• 批准号: 417186919
• 负责人: Dr. Takayuki Ishii, Ph.D.
• 金额: --
• 依托单位: Bayerisches Forschungsinstitut für Experimentelle Geochemie und Geophysik (BGI)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2020-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/417186919?language=en
• 关键词: pressure; temperature; phase; relations; basaltic

The chemical structure of the lower mantle remains under debate. The fate of subducting slabs is a key to answering the debate. In order to constrain dynamics of subducting slabs, phase relations of MORB under lower mantle conditions will be determined at pressures up to 50 GPa and temperatures of 1700, 2000 and 2300 K by means of the applicant’s original novel high-pressure generation technology of a Kawai-type multi-anvil press with tungsten carbide anvils. Using the compositions and proportions of constituent minerals in the MORB system determined in this project, density and seismic wave velocities of basaltic crust will be estimated. Based on these investigations, the roles of basaltic fragments of subducted slabs in mantle dynamics and possibility of the seismic detection of such fragments will be discussed.

下地幔的化学结构仍然存在争议。俯冲板块的命运是回答这一争论的关键。为了约束俯冲板块的动力学，将借助于申请人的具有碳化钨砧的Kawai型多砧压机的原始新颖高压产生技术，在高达50 GPa的压力和1700、2000和2300 K的温度下确定下地幔条件下的MORB的相关系。利用本项目确定的MORB系统中各组成矿物的成分和比例，估算玄武质地壳的密度和地震波速度。在此基础上，讨论了俯冲板片玄武岩碎块在地幔动力学中的作用以及地震探测这些碎块的可能性。