Collaborative Research: Tracing ca. 4 billion years of volatile cycling in magmas and fluids: insights from halogens in synthetic and natural zircons

合作研究：追踪大约。

• 批准号: 2240755
• 负责人: Dustin Trail
• 金额: $ 35.89万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2240755&HistoricalAwards=false
• 关键词: Collaborative; Research; Tracing; ca.; billion

Halogens (e.g., chlorine and fluorine) are key ingredients encountered in everyday life. They are found in consumer-based polymers (plastics), drinking water, toothpaste, swimming pools, cleaning supplies, and table salt. In the geosciences they represent one of the key components in ocean water; deeper into our planet, their concentration can affect whether a rock is a molten magma or crystalline at a given temperature. Halogens also affect the mobility and transport of critical elements in the crust like rare earth elements, cobalt, chromium, and copper etc. While researchers have some basic understanding of halogen interactions between the solid earth and the ocean/atmosphere, there is scant information about distribution and behavior of halogens during the very earliest times of our planet. These early times are important to understand because it is this information that serves as inputs into models that seek to understand the present and future state of Earth. This research will help to understand the complex connections between: (1) halogens inside of Earth’s rocks and (2) the ocean/atmosphere, and the movement between (1) and (2) through time. Since there is precious little information from the earliest Earth, the research team will rely upon a robust geochemical repository (the mineral zircon which resists physical and chemical weathering with ages that extend back to 4.4 billion years), carefully designed laboratory experiments, and mass spectrometry. This work will educate undergraduate/graduate students in mineralogy, state-of-the art experimental geochemistry/materials science, and mass spectrometry. These training opportunities have applications that extend beyond the geosciences. Halogen measurements of these Archean and Hadean zircons will be combined with high-temperature and high-pressure laboratory partitioning experiments to provide context for halogen-in-zircon geochemistry. Together, this information will be used to explore different halogen cycling models that may have prevailed on the early Earth, the outcome of which would have direct consequences for the composition of the early crust and possibly early Earth surface water chemistry. This research will yield the first ever detailed F and Cl partition coefficients between zircon-melt and zircon-fluid. Results will also be used to constrain the F and Cl contents of early Earth igneous systems (zircon-melt). In addition, zircon-fluid partition coefficients will be applied to a previously identified suite of ~3.9 billion- year-old zircons, which crystallized below the wet granite solidus and may record significant early Archean metamorphic or fluid-flow events. The partitioning studies will enable a broad characterization of halogen exchange between the crust-hydrosphere system and the mantle of the early Earth. Diffusion studies for Cl and F in zircon will be carried out to better establish the conditions under which zircon will retain primary Cl and F. Finally, new Cl- and F-in-zircon analyses will be undertaken, to better characterize terrestrial halogen cycling. The PI will train a PhD student in high P and T experimentation, electron microscopy, and mass spectrometry. Second, the course “Principles of Experimental Geochemistry”, will be offered as an upper division hybrid lecture- laboratory-based course designed as an active learning ‘studio’ format. Third, an undergraduate student will conduct laboratory research directly related to the objectives of this proposal, leading to a senior research thesis. And finally, the PI will design and build a simple petrographic microscope to enable mineral viewing in plane polarized and cross polarized light to develop a simple educational lesson, using the features of this microscope, for 8-12th grade students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

卤素（例如氯和氟）是日常生活中遇到的关键因素。它们是在基于消费者的聚合物（塑料），饮用水，牙膏，游泳池，清洁用品和餐盐中发现的。在地球科学中，它们代表了海水中的关键组成部分之一。深入我们的行星，它们的浓度会影响岩石在给定温度下是熔融岩浆还是结晶。卤素还会影响地壳中关键因素的活动性和运输，例如稀土元素，钴，铬和铜等。尽管研究人员对固体地球与海洋/大气之间的卤素相互作用有一些基本的了解，但在我们星球上很早的时候，关于卤素的分布和行为的信息很少。这些早期时期很重要，因为这是该信息是试图理解当前和未来地球状态的模型的输入。这项研究将有助于理解：（1）地球岩石内部和（2）海洋/大气层以及（1）和（2）之间的运动。由于最早的地球几乎没有宝贵的信息，因此研究团队将依靠强大的地球化学储存库（矿物锆石抵抗物理和化学风化的年龄，可追溯到44亿年），精心设计的实验室实验和质谱法。这项工作将教育矿物学，最先进的实验地球化学/材料科学和质谱学的本科/研究生。这些培训机会的应用超出了地球科学。这些大帝和hadean锆石的卤素测量将与高温和高压实验室分配实验相结合，为卤素内地球化学提供背景。总之，这些信息将用于探索可能在地球早期盛行的不同的卤素自行车模型，其结果将对早期地壳和可能早期地面地表水化学的组成产生直接影响。这项研究将产生锆石和锆石 - 流体之间的第一个详细的F和CL分区系数。结果还将用于约束地球火成岩系统（锆石融合）的F和CL含量。此外，锆石流体分区系数将应用于先前识别的约39亿年历史的锆石的套件，该套件在湿的花岗岩固体下面结晶，并可能记录大量早期的Archean变质或流体流动事件。分区研究将使地壳 - 水圈系统和早期地球架之间的卤素交换具有广泛的特征。将对锆石中CL和F进行扩散研究，以更好地确定锆石将保留原发性CL和F的条件。最后，将进行新的Cl-和F-In-Zircon分析，以更好地表征陆生卤素循环。 PI将在高P和T实验，电子显微镜和质谱法中训练一名博士生。其次，“实验地球化学原理”课程将作为上级混合讲座 - 基于实验室的课程，旨在作为主动学习的“ studio”格式。第三，一名本科生将与该提案的目标直接进行实验室研究，从而导致高级研究论文。 And finally, the PI will design and build a simple petrographic microscope to enable mineral viewing in plane polarized and cross polarized light to develop a simple educational lesson, using the features of this microscope, for 8-12th grade students.This award reflects NSF's statutory mission and has been deemed honestly of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.