CAREER: Studies of Magnesium Isotope Geochemistry

职业：镁同位素地球化学研究

• 批准号: 1056713
• 负责人: Fangzhen Teng
• 金额: $ 45.89万
• 依托单位: University of Arkansas
• 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: 2011-05-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1056713&HistoricalAwards=false
• 关键词: CAREER; Studies; Magnesium; Isotope; Geochemistry

The distribution of elements and isotopes in the Earth is important for understanding its formation and evolution. Compared to the 'building blocks' of the Earth, i.e., chondrites, the present solid Earth is highly heterogeneous, with a thin felsic crust, thick mafic mantle, liquid outer core and solid inner core. The extent to which these different reservoirs interacted with each other and evolved over time is still not well-constrained. This CAREER award investigates the origin, evolution and interactions between and among major Earth reservoirs through studies of magnesium isotope geochemistry by graduate and undergraduate students under the mentorship of the PI. The research results will be integrated with the educational process to promote student creativity and independent problem solving abilities, to broaden participation and increase the number of underrepresented undergraduate students in Geosciences and contribute to a broader community, through the development of application-oriented projects and new course design, through recruitment of African American students via a recently installed partnership for a Dual Degree Program between Fort Valley State University (FVSU) and University of Arkansas (UA), by providing research opportunities and summer research experiences for undergraduates and high-school students, and by providing professional development opportunities to community college teachers.Magnesium isotope geochemistry is still in its infancy. Few studies are available on Mg isotopic composition of the major solid Earth reservoirs and the degree to which Mg isotopes can fractionate during high-temperature geological processes. Following recent studies by the PI and other groups on the geochemical composition of the upper crust and the mantle, it is proposed to systematically investigate Mg isotopic variations in major Earth reservoirs and examine the processes and mechanisms that may produce these variations through studies of globally distributed, chemically diverse, well-characterized rocks and minerals. The results of the proposed research will advance the knowledge and state of the art of Mg isotope geochemistry and lay the foundation for using Mg isotopes as a tracer of crust-mantle interaction, as a high-precision geothermometry in igneous and metamorphic rocks, and as a speedometer to constrain the rates of crystal growth, cooling of magma and metamorphic events. Furthermore, the proposed research will enable the PI to establish for the first time a cutting-edge high-temperature geochemistry program at Arkansas and help UA to build the first PhD program in this area of research. The CAREER award will support one PhD student, one master student and multiple undergraduates, and support women and minorities to work in the lab (11 out of 16 students in the PI's lab are female, including one African American and one veteran). The PI will continue mentoring international young researchers, supporting community college teachers to work in the lab and serving the scientific community for Mg isotopic analysis. Results from the proposed work will be reported in conferences and peer-reviewed journals by students, postdocs and the PI, and eventually introduced into the PI's courses.

地球中元素和同位素的分布对于了解地球的形成和演化非常重要。与地球的“构件”（即球粒陨石）相比，目前的固体地球是高度异质的，具有薄的长英质地壳、厚的镁铁质地幔、液体外核和固体内核。这些不同的储层随着时间的推移相互作用和演化的程度仍然没有得到很好的限制。该职业奖通过研究生和本科生在 PI 的指导下对镁同位素地球化学的研究，研究主要地球储层之间的起源、演化和相互作用。研究成果将与教育过程相结合，通过开发应用型项目和新的项目，提高学生的创造力和独立解决问题的能力，扩大参与范围并增加地球科学领域代表性不足的本科生数量，并为更广泛的社区做出贡献。课程设计，通过最近建立的谷堡州立大学 (FVSU) 和阿肯色大学 (UA) 之间的双学位项目合作伙伴关系招募非裔美国学生，为本科生和高中生提供研究机会和暑期研究经验，并通过提供专业为社区大学教师提供发展机会。镁同位素地球化学仍处于起步阶段。关于主要固体地球储层的镁同位素组成以及高温地质过程中镁同位素分馏程度的研究很少。继PI等近期对上地壳和地幔地球化学成分的研究之后，提出通过研究全球分布的镁同位素变化，系统研究地球主要储层的镁同位素变化，并探讨可能产生这些变化的过程和机制。 、化学成分多样、特征良好的岩石和矿物。所提出的研究结果将推进镁同位素地球化学的知识和最新技术，并为使用镁同位素作为壳幔相互作用的示踪剂、作为火成岩和变质岩的高精度地温测量以及作为限制晶体生长、岩浆冷却和变质事件速率的速度计。此外，拟议的研究将使 PI 能够在阿肯色州首次建立尖端的高温地球化学项目，并帮助 UA 建立该研究领域的第一个博士项目。职业奖将支持一名博士生、一名硕士生和多名本科生，并支持女性和少数族裔在实验室工作（PI 实验室的 16 名学生中有 11 名是女性，其中包括一名非裔美国人和一名退伍军人）。 PI 将继续指导国际年轻研究人员，支持社区大学教师在实验室工作，并为科学界提供镁同位素分析服务。拟议工作的结果将由学生、博士后和 PI 在会议和同行评审期刊上报告，并最终引入 PI 的课程中​​。