CAREER: Visualizing Earth's Core-Mantle Interactions using Nanoscale X-ray Tomography

职业：使用纳米级 X 射线断层扫描可视化地球的核心-地幔相互作用

• 批准号: 1055454
• 负责人: Wendy Mao
• 金额: $ 48.63万
• 依托单位: Stanford University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-10-01 至 2018-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1055454&HistoricalAwards=false
• 关键词: CAREER; Visualizing; Earth; Core; Mantle

Core formation represents a pivotal event in the history of the Earth and other planetary bodies. A number of mechanisms have been proposed for how the core and mantle separate and interact; their validity, however, must be tested by direct experimental simulations which have not been previously possible. The investigator has been developing a new method to use nanoscale X-ray computed tomography (nanoXCT) to capture images of materials at high pressure. It is proposed to use this novel x-ray imaging technique to study how minute amounts of iron and silicate minerals interact at ultrahigh pressures and temperatures in order to shed light on the separation of Earth's rocky mantle from its iron-rich core. As a picture is worth a thousand words, x-ray imaging research is also easily accessible to students and to the broader public, and the visualization of how Earth's core and mantle materials interact presented in 3D movie format provides an attractive tool for education and outreach. In California, teaching Earth Science as part of the curriculum is only required in the 6th grade, so this is a critical time for young girls to develop an interest in science and a unique opportunity to engage all students in the fields of Geosciences. One of the main outreach activities is to develop a working partnership with a Girls' Middle School through the design of activities that will relate x-ray tomography to seismic tomography, which the students will already have been exposed to through the MARGINS program. The goal of this CAREER proposal is to improve our understanding of the Earth's deep interior focusing on developing high resolution nanoscale x-ray computed tomography (nanoXCT) to visualize Earth's core-mantle interactions. NanoXCT represents a powerful non-destructive, nanoscale resolution 3D probe which when coupled with a diamond anvil cell enables imaging of multiple minerals and amorphous phases (including melts) which are synthesized under extreme conditions. NanoXCT will be used to determine the texture and shape of molten iron and solid silicate minerals as they respond to the same intense pressures and temperatures found deep in the Earth will provide a test for potential mechanisms of core formation. Measurements of the shape of the melt pockets and channels formed by the putative partial melt which may exist in the layer just above the core-mantle boundary will provide insight into this complex region. With the added third dimension, higher resolution, and extension to very high pressures and temperatures, nanoXCT provides exciting new imaging opportunities for many fields beyond Earth Sciences.

地核的形成是地球和其他行星体历史上的一个关键事件。对于地核和地幔如何分离和相互作用，已经提出了一些机制;然而，它们的有效性必须通过以前不可能的直接实验模拟来测试。研究人员一直在开发一种新方法，使用纳米级X射线计算机断层扫描（nanoXCT）在高压下捕获材料的图像。建议使用这种新颖的X射线成像技术来研究微量的铁和硅酸盐矿物如何在超高压和超高温下相互作用，以揭示地球岩石地幔与富含铁的核心的分离。由于一张图片胜过千言万语，X射线成像研究也很容易为学生和更广泛的公众所接受，并且以3D电影格式呈现的地球核心和地幔物质如何相互作用的可视化为教育和推广提供了一个有吸引力的工具。在加州，教学地球科学作为课程的一部分，只需要在六年级，所以这是一个关键的时间，年轻女孩发展对科学的兴趣和独特的机会，让所有学生在地球科学领域。 主要的推广活动之一是与一所女子中学建立工作伙伴关系，设计活动，将X射线断层摄影术与地震断层摄影术联系起来，学生们已经通过MARGINS方案接触到了地震断层摄影术。这项职业计划的目标是提高我们对地球深部内部的理解，重点是开发高分辨率纳米级X射线计算机断层扫描（nanoXCT），以可视化地球的核幔相互作用。NanoXCT是一种功能强大的非破坏性纳米级分辨率3D探头，当与金刚石对顶砧单元耦合时，可以对在极端条件下合成的多种矿物和非晶相（包括熔体）进行成像。NanoXCT将用于确定熔融铁和固体硅酸盐矿物的质地和形状，因为它们对地球深处发现的相同强烈压力和温度的反应将为核心形成的潜在机制提供测试。 熔融袋和通道的形状的测量所形成的假定的部分熔体可能存在于层的核幔边界的上方，将提供洞察这个复杂的区域。随着增加的第三维，更高的分辨率和扩展到非常高的压力和温度，nanoXCT为地球科学以外的许多领域提供了令人兴奋的新成像机会。