RII Track-4: Using Novel Applications of Luminescence Techniques to Evaluate Channel Mobility and Bedrock Valley Development

非技术描述河流系统通过侵蚀和沉积沉积物，记录了过去地球表面气候、水文、植被和构造过程的变化。虽然对基岩景观的垂直侵蚀进行了广泛的研究，但关于河流如何在基岩景观中横向侵蚀的问题上几乎没有达成共识。为了了解河流动态的变化如何塑造地球表面，确定形成基岩山谷的横向加宽间隔的持续时间是至关重要的。通过与沙漠研究所(DRI)的合作，PI将学习发光测年技术，这将使她能够确定横向侵蚀间隔的时间，并应用这些技术来推断沉积物的运移历史。确定过去和现在的河流切割时间对于预测正在进行的景观变化对居住和工作在堪萨斯州河流附近的人类的影响很重要，堪萨斯州是PI的家乡。PI的总部机构堪萨斯州立大学将受益于PI的专业发展，她与DRI扩展的合作网络，以及在研究和教学中纳入测年技术，以展示当地河流如何在十年和百年的时间尺度上变化，人类必须做好准备适应这些变化。技术描述控制基岩河流垂直切割的过程得到了广泛的研究和很好的表征；然而，控制横向侵蚀的基本过程还没有在实验室或现场量化。描述过去河道流动性并确定横向冲刷间隔长度的绝对时间限制的现场数据，对于更好地了解导致宽阔基岩山谷的条件至关重要。发光特性的分析是确定河流沉积的侧向侵蚀和垂直切割时期的关键工具。它还有可能阐明泥沙淤积期间的输运过程，如河道的流动性。在该项目期间进行的研究有可能改变我们对基岩河谷系统演化过程和时间的理解。两个主要项目目标支持总体目标：(1)学习单颗粒发光技术，以确定具有复杂运移历史的沉积物的沉积年龄；(2)解释发光特性，将其作为河流过程的替代指标，如河道迁移率。使用发光技术来解释地貌过程是一种新兴的应用，它有可能给人带来超越年代的洞察。当这个项目完成后，地貌界将更接近于将发光特性解释为运输过程的代理，以评估与基岩山谷形成时期相关的沉积物过去的河道流动性，并最终成为解释大量已测量但以前未经检查的数据的新方法。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical DescriptionBy eroding and depositing sediment, river systems record past changes in climate, hydrology, vegetation, and tectonic processes on the Earth's surface. While vertical erosion into bedrock landscapes has been extensively studied, there is little consensus on how rivers erode laterally in bedrock landscapes. It is crucial to establish the duration of lateral widening intervals that create bedrock valleys in order to understand how changes in river dynamics shape the Earth's surface. Through a collaboration with the Desert Research Institute (DRI), the PI will learn luminescence dating techniques that will allow her to establish the timing of lateral erosion intervals and apply these techniques to infer transport history of sediments. Determining the timing of past and current river incision is important for predicting the effect of ongoing landscape change on humans who live and work near rivers in Kansas, the PI's home state. The PI's home institution, Kansas State University, will benefit from the professional development of the PI, her extended collaborative network with DRI, and the incorporation of dating techniques in research and teaching to demonstrate how local rivers change on decadal and centennial time scales that humans must be prepared to adapt to.Technical DescriptionThe processes that control vertical incision in bedrock rivers are widely studied and well characterized; however, the fundamental processes that control lateral erosion have not been quantified in the laboratory or in the field. Field data that describes past channel mobility and defines absolute time constraints on the length of lateral erosion intervals are vital for better understanding the conditions that result in wide bedrock valleys. Analysis of luminescence properties is a key tool for dating fluvial deposits to determine periods of lateral erosion and vertical incision. It also has the potential to illuminate transport processes, such as channel mobility, during periods of sediment deposition. Research conducted during this project has the potential to transform our understanding about the processes and timing of the evolution of bedrock valley systems. Two main project objectives support the overarching goals: (1) learning single-grain luminescence techniques to date the depositional age of sediments with complex transport histories; (2) interpreting luminescence properties as a proxy for fluvial processes, such as channel mobility. Using luminescence techniques to interpret geomorphic processes is an emerging application that has the potential to give insight beyond dating. When this project is complete, the geomorphology community will be closer to interpreting luminescence properties as proxies of transport processes to assess past channel mobility from sediment deposited in association with periods of bedrock valley formation and ultimately a new way of interpreting a wealth of measured, but previously unexamined data.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.