Aluminum- and Iron-rich Perovskites and Post-perovskites and Earth's Deep Lower Mantle

富含铝和铁的钙钛矿和后钙钛矿以及地球深层下地幔

• 批准号: 0838017
• 负责人: Thomas Duffy
• 金额: $ 25.18万
• 依托单位: Princeton University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838017&HistoricalAwards=false
• 关键词: Aluminum; Iron; rich; Perovskites; Post

Understanding the deep interior of the Earth is a key ingredient in unraveling the processes involved in the origin and evolution of our planet. In addition, the geological activity that manifests itself so profoundly at the surface of the Earth has its ultimate origins in processes ongoing in the deep interior. Studying minerals under the extreme pressure-temperature conditions of the deepest Earth provides a means to test the limits of our understanding of basic physical and chemical properties of materials. The Earth's core-mantle boundary is particularly complex as it juxtaposes the churning liquid iron core against the hot but solid silicate minerals of the deep mantle at greater than a million times atmospheric pressure. In this work, we propose to recreate the conditions of Earth's deep mantle in the laboratory and study the detailed nature of the crystal structures that form under such conditions and their physical properties.The Earth's core-mantle boundary region (called D") is a thin layer (~200 km thick) lying just above the core that has long been of interest due to its unusual seismic properties. Perovskites (Pv) and post perovskites (pPv) are expected to be the major mineral phases of Earth's lower mantle and core-mantle boundary regions. Seismic evidence indicates the deep lower mantle exhibits considerable chemical heterogeneity and this may result from such phenomena as core-mantle interactions, partial melting in D", retained primordial material, or accumulation of subducting slabs. This chemical complexity will influence many key properties of the deep mantle including location and width of phase boundaries, density, sound velocities, element partitioning, and transport and thermal properties. In this project, the investigators will use synchrotron x-ray diffraction and scattering techniques to explore the behavior of iron- and aluminum-bearing perovskites and post-perovskites over a wide pressure range. They will synthesize a variety of phases at conditions up to 200 GPa and 2500 K and measure such properties as equations of state, compressibilities, phase boundaries, and Clapeyron slopes. This study of chemically complex systems at high pressures and temperatures will enable a better interpretation of seismically observed deep mantle structure in terms of the physical and chemical properties of realistic mineral assemblages. The proposed research will yield advances in understanding the geochemistry and thermoelastic properties of minerals of relevance for the Earth's deep mantle, and will impact the fields of mineral physics, geodynamics, seismology, and petrology.

了解地球的深层内部是揭示我们星球起源和演变所涉及的过程的关键要素。 另外，在地球表面如此深刻地表现出自己的地质活动具有最终的起源，这是深层内部正在进行的过程。 在最深地球的极端压力温度条件下研究矿物质提供了一种测试我们对材料基本物理和化学特性的理解的局限性的方法。 地球的核心壳边界特别复杂，因为它将搅拌的液态铁芯与深地幔的热但实心硅酸盐矿物并列，以大于100万倍的大气压力。 在这项工作中，我们建议在实验室中重新创建地球深地幔的条件，并研究在这种情况及其物理特性下形成的晶体结构的详细性质。地球的核心核心边界区域（称为d“）是薄层（〜200 km厚），这是在核心上方的核心（约200 km厚）。成为地球下地幔和核心掩护边界区域的主要矿物阶段。 这种化学复杂性将影响深层地幔的许多关键特性，包括相位边界的位置和宽度，密度，声速，元素分配以及运输和热性能。 在这个项目中，研究人员将使用同步加速器X射线衍射和散射技术来探索在较大的压力范围内铁和铝制钙晶的行为以及植物后的行为。 他们将在最高200 GPA和2500 K的条件下合成各种阶段，并测量诸如状态方程，压缩性，相边界和Clapeyron斜率之类的特性。 这项对高压和温度下化学复杂系统的研究将可以更好地解释地震观察到的深陆壁结构，从现实矿物组合的物理和化学特性方面。 拟议的研究将在理解地球矿物质相关性的地球化学和热弹性特性方面产生进展，并将影响矿物质物理学，地球动力学，地震学和岩石学领域。