EAR-PF: Investigating the effects of bedrock dip angle on knickpoint morphology and evolution via flume experimentation and numerical modeling

Kristin Chilton博士被授予NSF EAR博士后奖学金，以研究河床上岩石裂缝(裂缝)的方向如何影响岩石通过瀑布(也称为临时瀑布)流动而被侵蚀(磨损)的难易程度。关键点通常是河流内集中侵蚀的区域，该项目将涉及创造性设计的实验，以检验裂缝在控制河流侵蚀成岩石方面的作用。这项研究的结果将使科学家能够更好地预测地球表面将如何随着时间的推移而变化，从我们今天看到的景观中解读气候和地质历史，并改进重要基础设施的安全和寿命的工程设计。这项工作将在弗吉尼亚理工大学和西弗吉尼亚大学分别与导师凯尔·斯特罗姆博士和查尔斯·肖布博士合作进行。奇尔顿博士的项目还将为本科生参与学术研究提供机会，通过夏季推广计划支持STEM领域的多样性，并通过关注河流侵蚀过程的教育视频和博客文章向更广泛的受众介绍地球科学主题。该项目的主要目标是测试不连续面(可以是裂缝、节理或层面)的方向如何影响点点内基岩块的水力采摘，从而影响点点形态和演化。这将通过一系列水槽实验来实现，这些实验将使用堆叠的瓷砖来模拟不同倾角的层状沉积基岩，并持续监测拐点形态、后退速度和拔毛事件。然后，水槽实验的结果将被整合到数字景观演变模型中，以将影响扩展到更广泛的空间和时间尺度。这项调查将填补我们对基岩河道形态和河流切割过程的基本控制的理解上的一个关键空白，通过结合特定的基岩特征来提高景观演变模型的稳健性，并通过表征对点点形式和速度的潜在控制来帮助确保适当地将点点作为气候和隆起历史的指示器。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。

Dr. Kristin Chilton has been awarded an NSF EAR Postdoctoral Fellowship to investigate how the orientation of rock fractures (cracks) in river beds influences the ease with which that rock is eroded (worn away) by flowing over waterfalls (also called knickpoints). Knickpoints are often zones of concentrated erosion within rivers and this project will involve creatively designed experiments that examine the role of cracks in controlling river erosion into rock. The results of this study will allow scientists to better predict how Earth’s surface will change over time, interpret climatic and geologic histories from the landscapes we see today, and improve engineering designs for the safety and longevity of important infrastructure. The work will be carried out at Virginia Tech and West Virginia University in collaboration with mentors, Dr. Kyle Strom and Dr. Charles Shobe, respectively. Dr. Chilton’s project will also provide opportunities for undergraduate involvement in academic research, support diversity in STEM fields through summer outreach programs, and introduce a broader audience to Earth science topics via educational videos and blog posts focused on river erosion processes. The primary goal of this project is to test how the orientation of discontinuities (which can be fractures, joints, or bedding planes) influences hydraulic plucking of bedrock blocks within knickpoints, and therefore knickpoint morphology and evolution. This will be accomplished via a series of flume experiments, which will use stacked porcelain tiles to simulate layered sedimentary bedrock at various dip orientations, coupled with continuous monitoring of knickpoint morphology, retreat rate, and plucking events. The results of the flume experiments will then be integrated into numerical landscape evolution models to expand implications to broader spatial and temporal scales. This investigation will fill a critical gap in our understanding of the fundamental controls on bedrock channel morphology and fluvial incision processes, improve robustness of landscape evolution models by incorporating specific bedrock characteristics, and help ensure appropriate interpretation of knickpoints as indicators of climatic and uplift history by characterizing a potential control on knickpoint form and celerity.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.