CAREER: Accessory Minerals as Monitors of the Oxidation State of Magmas and Fluids and Enhancing Scientific Literacy Through Active Education

在几乎所有情况下，我们都无法直接测量控制地球内部岩浆和流体性质的关键变量。 由于它们的形成深度，或者因为这些岩浆早已凝固，留下了矿物，所以它们不能直接进入。 因此，需要使用所产生的矿物的化学性质作为替代物，以确定这些岩浆和流体的物理和化学特征。 一个关键的变量，仍然很少探索的副组矿物（如，锆石、独居石和磷灰石）是它们结晶的岩浆或流体的氧“压力”。 这项研究的目的是校准和了解这些矿物质的化学性质如何随着氧气压力的变化而变化。 这些校准将在实验室环境中进行，以便在精确控制的条件下合成矿物。这些实验将成为探索天然矿物形成环境的垫脚石。 副矿物锆石、独居石和磷灰石是专门针对的，因为它们是绝对时间的优秀记录器。 这是因为它们在结构上容纳了放射性元素，如铀和钍。 因此，例如，岩浆中氧压的变化可以作为时间的函数来探索。 氧气压力是地球研究中的一个重要变量，因为它影响矿物的饱和度和稳定性（包括经济上重要的矿物）以及岩浆的粘度。 正因为如此，量化过去系统的氧气压力，包括古代火山系统，将导致新的知识，可能有助于解释火山爆发的原因。 第二，火山爆发时存在的挥发物类型取决于氧气压力，这意味着整个地球历史上的岩浆释气部分影响了我们大气的组成。 第三，本研究将探讨这些矿物在氧化流体中的稳定性。 例如，独居石是地壳中轻稀土元素、钍和铀的主要来源。了解这种矿物的稳定性和溶解性也将有助于研究人员探索这些关键的发热和经济重要元素的流动性（稀土元素几乎存在于今天制造的所有现代电子产品中）。最后，年龄超过40亿年的矿物（锆石）是应用的关键目标，因为这个时期的岩石要么稀少，要么完全不存在。因此，这项工作将导致对早期地球上可能存在的环境和条件的新知识。 氧逸度缓冲实验将在罗切斯特大学的活塞气缸装置中进行。 在许多情况下，PI、研究生和本科生将通过激光烧蚀电感耦合等离子体质谱仪（LA-ICP-MS;也在罗切斯特大学）分析实验产品。 这将为本科生和研究生提供矿物合成和质谱技术方面的关键培训，其应用范围远远超出地质学/矿物学领域。 IPC-MS仪器已用于医学研究，生物学，化学和材料科学，因此学生将获得适用于STEM领域的有用技能。 此外，学生将接受X射线吸收近边结构（XANES）技术的培训;这项工作将在先进光子源，阿贡国家实验室进行。 实践培训将导致广泛的技能，高度适用于地球科学内外的许多领域。 该项目的更广泛影响来自实施主动学习的几项活动。 该奖项将使合作伙伴关系与NSF资助的诺伊斯计划授予华纳教育学院在罗切斯特大学。 PI将与纽约北部高需求城市地区选定的K-12数学和科学教师研究员合作-目前的毕业率低于50% -以提高科学素养，更好地理解人们学习的不同方式，让教师接触新的和不断发展的教学方法，并创造更有趣，更有意义的学习体验，对他们的学生来说是有效的。 最后，PI将设计一门新课程，探索与传统讲座相比已被证明有效的教学策略。 该课程还将围绕本提案中确定的研究问题进行建设。该奖项反映了NSF的法定使命，并且通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

In almost all cases, we cannot directly measure key variables that control the properties of magmas and fluids inside the Earth. They are not directly accessible due to their depth of formation, or because these magmas have long since solidified, leaving behind minerals. Thus, the chemistry of the resulting minerals need to be used as proxies, to determine the physical and chemical characteristics of these magmas and fluids. One key variable that remains poorly explored in the accessory group of minerals (e.g., zircon, monazite, and apatite) is the oxygen "pressure" of the magma or fluid from which they crystallized. The goal of this research is to calibrate and understand how the chemistry of these minerals changes in response to changes in the oxygen pressures. These calibrations will take place in a laboratory setting enabling the synthesis of minerals under precision-controlled conditions. Such experiments will serve as stepping stones to explore the formation environment of natural minerals. The accessory minerals zircon, monazite, and apatite are specifically targeted because they are excellent recorders of absolute time. This is so because they structurally accommodate radioactive elements such as uranium and thorium. Thus, changes in the oxygen pressure of a magma can, for example, be explored as a function of time. Oxygen pressure is an important variable in Earth studies because it influences mineral saturation and stability (including economically important minerals) and the viscosity of magmas. Because of this, quantifying the oxygen pressure of past systems, including ancient volcanic systems, will lead to new knowledge to that may help explain why volcanoes erupt. Second, the types of volatiles present during an eruption depends on oxygen pressure, and meaning that magmatic outgassing throughout Earth history has partially influenced the composition of our atmosphere. Third, this research will explore the stability of these minerals in the presence oxidized fluids. Monazite, for instance, is a major host of light rare earth elements, thorium, and uranium in the crust. Understanding the stability and solubility of this mineral will also help researchers explore the mobility of these key heat producing and economically important elements (rare earth elements are found in almost all modern electronics manufactured today). And finally, minerals (zircons) older than 4 billion years represent a key target for application because rocks from this time period are either sparse or altogether absent. This work will therefore result in new knowledge about the environments and conditions that may have prevailed on the earliest Earth. Oxygen fugacity buffered experiments will be conducted in piston cylinder devices at the University of Rochester. In many cases, experimental products will be analyzed by a Laser Ablation Inductively Couple Plasma Mass Spectrometer (LA-ICP-MS; also at the University of Rochester) by the PI, graduate, and undergraduate students. This will provide key training for undergraduates and graduate students in techniques involved in mineral synthesis and mass spectrometry, with applications that extend well beyond the geology/mineralogy field. (LA)-IPC-MS instruments have been used in medical research, biology, chemistry, and materials science, so students will come away with a useful skill set applicable across the STEM fields. In addition, students will receive training in X-ray Absorption Near Edge Structure (XANES) techniques; this work will be undertaken at the Advanced Photon Source, Argonne National Laboratory. The practical training will result in a broad skill set, highly applicable to many areas within and outside the geosciences. The broader impacts of this project come from several activities that implement active learning. This award will enable a partnership with NSF-Funded Noyce program awarded to the Warner School of Education at the University of Rochester. The PI will work with selected K-12 math and science teacher fellows in high-need urban districts in upstate New York - current graduate rates are below 50% - to increase science literacy, to create a better understanding of the different manners in which people learn, to expose teachers to new and evolving methods of teaching, and to create learning experiences that are more interesting, meaningful, and effective for their students. And finally, the PI will design a new course to explore teaching strategies that have been demonstrated to be effective when compared to a traditional lecture. The course will also be built around a research problem identified in this proposal.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.