CSEDI Collaborative Res.: Composition and Seismic Structure of the Mantle Transition Zone

CSEDI协作研究：地幔过渡带的组成和地震结构

• 批准号: 0112256
• 负责人: Stephen Grand
• 金额: $ 16.5万
• 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: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2005-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0112256&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Res.; Composition; Seismic

Bass Grand The investigators propose a collaborative effort between a mineral physicist (J Bass, University of Illinois Urbana-Champaign) and a seismologist (S. Grand, University of Texas, Austin) aimed at elucidating the seismic structure and mineralogy of the Earth's transition zone, from 300-1000 km in depth. The seismic structure will be determined in several regions with unprecedented resolution of the velocity jumps across transition zone discontinuities and the seismic velocity gradients between the jumps. The available mineral elasticity data and phase relations for relevant mineral systems will be used to calculate the compositions and proportions of individual phases, and the properties of candidate mantle assemblages as a function of depth for a range of bulk compositions. Two key experiments on the high temperature and pressure elasticity of beta phase and aluminous perovskite will be done to fill in the most pressing gaps in the elasticity data base. A new waveform inversion code will be used to determine acceptable fits of mineralogic models directly to the seismic data within certain imposed constraints. For example, with the percent olivine component and size of discontinuities fixed, they can search for allowable models of gradients that satisfy seismic constraints. Other initial conditions will be tried as well. In this way the investigators propose to define both the structure of the transition zone and the range of mineralogical models which are compatible with the seismic data in a more formal quantitative way than has been done before. This research will involve one student working on mineral physics aspects of the project at UIUC, and a student working on the seismological aspects at UTA.

研究人员提议矿物物理学家（J Bass，伊利诺伊大学香槟分校）和地震学家（S. Grand，德克萨斯大学奥斯汀分校）合作，旨在阐明地球过渡带的地震结构和矿物学，深度300-1000公里。将以前所未有的分辨率跨越过渡带不连续性的速度跳跃和跳跃之间的地震速度梯度来确定几个区域的地震结构。相关矿物系统的可用矿物弹性数据和相关系将用于计算各个相的成分和比例，以及候选地幔组合的特性作为一系列散装成分深度的函数。将进行关于β相和铝钙钛矿高温高压弹性的两项关键实验，以填补弹性数据库中最紧迫的空白。新的波形反演代码将用于确定矿物学模型在某些施加的约束下直接与地震数据的可接受的拟合。例如，在橄榄石成分百分比和不连续性大小固定的情况下，他们可以搜索满足地震约束的允许梯度模型。其他初始条件也将被尝试。通过这种方式，研究人员建议以比以前更正式的定量方式定义过渡带的结构和与地震数据兼容的矿物学模型的范围。这项研究将涉及一名在 UIUC 从事该项目矿物物理方面工作的学生和一名在 UTA 从事地震学方面工作的学生。