CAREER: Chemical Heterogeneity in Earth's Lower Mantle

职业：地球下地幔的化学异质性

• 批准号: 0955824
• 负责人: Kanani Lee
• 金额: $ 60.22万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0955824&HistoricalAwards=false
• 关键词: CAREER; Chemical; Heterogeneity; Earth; Lower

The Earth's bulk composition is fundamental to the understanding of the formation and evolution of not only Earth but also other planets in our own and other solar systems. However, estimates of the composition of Earth's mantle, which comprises more than three-quarters of the Earth's volume and nearly two-thirds of its mass, remain controversial and elusive. The compositional makeup of this region is especially important for understanding chemical heterogeneity, which constrains deep structure and mixing and is crucial for inferring the thermo-chemical evolution of the Earth, from planet building and the magma ocean, to continental growth and the formation of the oceans and atmosphere. Investigations of natural rock assemblages that have compositions that include aluminum and calcium in addition to oxygen, silicon, magnesium and iron, have suggested that the upper and lower mantle are chemically distinct and that the transition zone may not only involve a change in mineral structure but may also mark a quasi-compositional boundary. There are several candidates for the 'natural' bulk Earth composition, and in this CAREER award she seeks to investigate the properties and signatures of these under extreme conditions. For example, two plausible lower-mantle compositions include one derived from the building blocks of the planet and another derived from parent bodies of ocean island basalts. Investigating the behavior of these compositions at high pressures and temperatures will test hypotheses on Earth's formation, elucidate the geochemistry of the deep mantle, and determine if mantle reservoirs of varying composition are seismologically identifiable. The proposed mineral physics research uses extreme experimental conditions designed to reproduce and 'probe' the Earth's deep interior, and the exploration of such inaccessible regions is readily disseminated to the public through multimedia and graphical approaches. In particular, the PI proposes a novel way of teaching Earth science through the use of comics, in both printed and digital form. In doing so, the PI will be able to make topics such as Earth formation and evolution more accessible to students in the New Haven Public Schools System, as well as to the general public through online publication. Another integral part of this proposal is the training of graduate and undergraduate students in high-pressure mineral physics research through laser-heated diamond-anvil cell experiments at national synchrotron facilities. This training will contribute to the education of the next generation of independent researchers who will possess a thorough knowledge of high-pressure experiments that impact our understanding of the transfer of mass and energy within our planet. The proposed research will be carried out at facilities of all scales (PI's laboratory, departmental, national and international laboratories) and results will be disseminated broadly through teaching, community outreach, seminars, conferences and peer-reviewed publications.

地球的整体组成不仅对理解地球的形成和演变至关重要，而且对理解我们自己和其他太阳系中其他行星的形成和演变也至关重要。然而，对地球地幔组成的估计仍然存在争议和难以捉摸，地幔占地球体积的四分之三以上，质量的近三分之二。 这一地区的成分构成对于理解化学异质性特别重要，化学异质性限制了深部结构和混合，对于推断地球的热化学演化至关重要，从行星建造和岩浆海洋到大陆生长以及海洋和大气的形成。 对天然岩石组合的研究表明，除了氧、硅、镁和铁之外，还包括铝和钙，这表明上地幔和下地幔在化学上是不同的，过渡区不仅可能涉及矿物结构的变化，而且可能标志着准成分边界。 有几个候选人的“自然”散装地球组成，并在这个职业奖，她试图调查这些极端条件下的属性和签名。 例如，有两种合理的下地幔成分，一种来自地球的构造块，另一种来自海洋岛屿玄武岩的母体。研究这些成分在高压和高温下的行为将测试地球形成的假设，阐明深部地幔的地球化学，并确定不同成分的地幔储层是否可以在地震学上识别。拟议的矿物物理学研究使用极端的实验条件，旨在再现和“探测”地球的深层内部，对这些无法进入的地区的探索很容易通过多媒体和图形方法向公众传播。特别是，PI提出了一种通过使用印刷和数字形式的漫画来教授地球科学的新方法。 通过这样做，PI将能够使地球形成和演化等主题更容易为纽黑文公立学校系统的学生以及通过在线出版物向公众提供。 这项建议的另一个组成部分是通过在国家同步加速器设施进行激光加热金刚石砧室实验，对研究生和本科生进行高压矿物物理学研究方面的培训。 这项培训将有助于下一代独立研究人员的教育，他们将拥有高压实验的全面知识，这些实验将影响我们对地球内部质量和能量转移的理解。 拟议的研究将在各种规模的设施（PI的实验室，部门，国家和国际实验室）进行，并将通过教学，社区宣传，研讨会，会议和同行评审的出版物广泛传播结果。