CAREER: Chemical Heterogeneity in Earth's Lower Mantle

地球的主体组成不仅对理解地球的形成和演化至关重要，而且对我们自己和其他太阳系中的其他行星的形成和演化也是如此。然而，对地幔的组成的估计仍然存在争议和难以捉摸。地幔的体积占地球体积的四分之三以上，质量占地球质量的近三分之二。该区域的组成对于了解化学不均质性特别重要，化学不均质性制约着深层结构和混合，对于推断地球从行星建造和岩浆海洋到大陆生长和海洋和大气的形成的热化学演化至关重要。对天然岩石组合的研究表明，上地幔和下地幔在化学上是不同的，过渡带可能不仅涉及矿物结构的变化，还可能标志着准成分边界。有几个候选的‘天然’块状地球成分，在这个职业奖项中，她试图研究这些元素在极端条件下的性质和特征。例如，两种看似合理的下地幔成分包括一种来自地球的构造块，另一种来自大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检验关于地球形成的假说，阐明深部地幔的地球化学，并确定不同成分的地幔储集层是否可在地震学上识别。拟议中的矿物物理研究使用了极端的实验条件，旨在重现和探测地球深处，对这种难以到达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将能够使纽黑文公立学校系统的学生以及通过在线出版的普通公众更容易接触到地球形成和进化等主题。这项提议的另一个组成部分是在国家同步加速器设施中通过激光加热的钻石砧座实验对研究生和本科生进行高压矿物物理研究方面的培训。这种培训将有助于教育下一代独立研究人员，他们将全面了解高压实验，这些实验影响了我们对地球内部质量和能量传递的理解。拟议的研究将在所有规模的设施(国际和平研究所实验室、部门实验室、国家实验室和国际实验室)进行，结果将通过教学、社区宣传、研讨会、会议和同行评议出版物广泛传播。

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.