GEO-CM: Prospecting for critical element deposits: an interdisciplinary approach using experimental geochemistry and field-informed modeling of sediment transport

钴、铌和锡等关键矿物是现代技术所需的重要资源。这些技术包括智能手机、电池、电动汽车和卫星。关键矿物是实现可持续能源经济所需的关键资源。然而，对这些矿物的需求可能很快就会超过现有的供应。此外，还存在国际供应链中断的风险。为了降低这些具有重大经济和国家安全影响的风险，该提案的目标是提高地球科学家在地球上发现更多这些关键矿产资源的能力。这个项目将创造新的工具来分析河流沉积物，主要有两个目标。首先，这项工作将确定上游是否有尚未发现的关键矿物。其次，该项目旨在定位这些矿物集中的上游地区。该项目将为一名博士生、一名博士后和多名本科生提供关键矿物研究方面的教育和培训。在本科地球材料课程中，一个重要的矿物模块将占大约2-3周的讲课时间。ppi还将与纽约州罗切斯特市的当地青年领导力和劳动力发展项目合作。该合作伙伴关系的目标是在夏季为来自代表性不足群体的学生提供环境研究和职业经验。想象一下，从河里捡一勺沙子；在那一勺中隐藏着关于整个流域岩石的信息。对沉积物颗粒的分析可能会揭示代用矿物中存在一种关键元素，表明该地区某处可能存在一种源岩。该项目探讨了两个问题：沉积物中矿物质中的微量元素浓度是否能识别出富含关键元素的潜在肥沃火成岩源？如果是这样，沉积物的运输历史是否可以用颗粒的物理特性（如形状和大小）来模拟，从而限制产生它的肥沃来源的可能位置？本工作的目的是通过结合高温室内实验对锆石、石英、金红石化学，这样它们就可以作为关键矿床的“指示矿物”，2)数值模拟和基于现场的沉积物示踪剂研究，将改进沉积物运输距离的预测和可行的关键矿物源岩的位置。对于第一个目标，该团队将使用实验地球化学在一种关键含元素矿物的存在下合成石英、锆石和金红石。这些实验将允许研究人员确定目标指示矿物中不同关键元素的阈值浓度，这将表明一个肥沃的来源。对于第二个目标，研究人员将使用耦合流体-颗粒数值模型，根据颗粒形状和大小建立新的泥沙输运距离统计分布。该团队还将使用带有rfid标签的岩石来跟踪两条天然河流中的沉积物运输，以确定沉积物的大小和形状如何影响它们在自然系统中的移动距离。这项基础性工作将为未来发展一个综合模型奠定基础，该模型仅从河流沉积物特性中预测关键矿物源岩的位置。这项建议的结果将超出矿产勘探；对沉积物从岩石中诞生到通过河流系统运输和降解的整个生命周期中所发生的过程，形成了一种新的观点，这对我们对地球物质和地球表面演化的基本理解具有重要意义。该奖项反映了美国国家科学基金会的法定使命，并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。

Critical minerals like cobalt, niobium, and tin are essential resources needed for modern technologies. These technologies include smartphones, batteries, electric vehicles, and satellites. Critical minerals are a key resource needed to move to a sustainable energy economy. However, the demand for these minerals could soon exceed the available supply. Additionally, there is a risk of disruptions in the international supply chain. To lower these risks, which carry significant economic and national security implications, the goal of this proposal is to increase geoscientists' abilities to find more of these critical mineral resources in the Earth. This project will create new tools to analyze river sediment with two main objectives. First, the work will determine whether critical minerals might be upstream that have not yet been discovered. Second, the project aims to locate places upstream where these minerals are concentrated. This project will provide education and training on critical mineral research to a PhD student, a postdoc, and multiple undergraduate students. A critical mineral module will make up approximately 2-3 weeks of lectures for an undergraduate Earth Materials course. The PIs will also partner with a local youth leadership and workforce development program in Rochester, NY. The goal of the partnership is to provide experience in environmental research and careers for students from underrepresented groups over the summer. Imagine collecting a scoop of sand from a river; hidden in that single scoop lies information about the rocks in the entire drainage basin. Analysis of the sediment grains may reveal the presence of a critical element of interest in a proxy mineral, indicating a source rock of possible interest somewhere in the area. This project explores two questions: Does the trace element concentration within minerals in sediment fingerprint a potentially fertile igneous source enriched in the critical element of interest? If it does, can the transport history of the sediment be modeled using physical properties of the grain such as shape and size to constrain the likely location of the fertile source that produced it? The goal of this work is to enhance prediction capabilities of undiscovered critical mineral-rich source rocks by using river sediments for prospecting by combining 1) high temperature laboratory experiments to characterize zircon, quartz, and rutile chemistry so that they can be used as “indicator minerals” for critical mineral deposits and 2) numerical modeling and field-based sediment tracer studies that will improve predictions of sediment transport distance and the location of viable critical mineral source rocks. For the first objective, the team will use experimental geochemistry to synthesize quartz, zircon, and rutile in the presence of a critical element bearing mineral. These experiments will allow the researchers to define the threshold concentrations of different critical elements in target indicator minerals that would suggest a fertile source. For the second objective, the investigators will use coupled fluid-granular numerical models to develop new statistical distributions of sediment transport distance depending on grain shape and size. The team will also use RFID-tagged rocks to track sediment transport in two natural rivers to determine how sediment size and shape affect their travel distances in natural systems. This fundamental work will set the stage for future development of a comprehensive model that predicts critical mineral source rock location from river sediment properties alone. Findings from this proposal will extend beyond mineral prospecting; developing a new view of the processes that occur during the lifetime of sediments, from birth within a rock to transport and degradation through a river system, has implications for the fundamental understanding of Earth materials and the evolution of Earth’s surface.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.