CAREER: Studies of Magnesium Isotope Geochemistry

职业：镁同位素地球化学研究

• 批准号: 1340160
• 负责人: Fangzhen Teng
• 金额: $ 43.97万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-12-16 至 2017-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1340160&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理解地球的形成和演化具有重要意义。与地球的“积木”相比，地球是一个高度不均匀的固体，有一个薄的长英质地壳，厚的镁铁质地幔，液态的外核和固态的内核。这些不同的储层相互作用和随时间演变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的指导下进行镁同位素地球化学研究，调查主要地球水库之间的起源，演变和相互作用。研究成果将与教育过程相结合，以促进学生的创造力和独立解决问题的能力，扩大参与，增加在地球科学代表性不足的本科生的数量，并有助于更广泛的社区，通过开发以应用为导向的项目和新的课程设计，通过最近建立的山谷堡州立大学（FVSU）和阿肯色州大学（UA）之间的双学位项目合作伙伴关系招募非洲裔美国学生，通过为大学生和高中生提供研究机会和暑期研究经验，并通过为社区学院教师提供专业发展机会，镁同位素地球化学仍处于起步阶段。关于主要固体地球储集层的Mg同位素组成以及Mg同位素在高温地质过程中的断裂程度的研究很少。在PI和其他小组最近对上地壳和地幔的地球化学组成进行研究之后，建议系统地调查主要地球储层中的Mg同位素变化，并通过研究全球分布的、化学多样性的、特征良好的岩石和矿物来检查可能产生这些变化的过程和机制。该研究成果将促进镁同位素地球化学的认识和发展，为镁同位素作为壳幔相互作用的示踪剂、火成岩和变质岩中的高精度地质测温方法、晶体生长速率、岩浆冷却速率和变质事件的速度计奠定基础。此外，拟议中的研究将使PI首次在阿肯色州建立一个尖端的高温地球化学项目，并帮助UA在这一研究领域建立第一个博士项目。职业奖将支持一名博士生，一名硕士生和多名本科生，并支持妇女和少数民族在实验室工作（PI实验室的16名学生中有11名是女性，包括一名非洲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。