CAREER: Tectonically dead but geomorphologically alive: Investigating the role of hard rocks as triggers of widespread, long-term landscape change in continent interiors

虽然对人类来说似乎是静态的，但流域-以及它们所承载的河流网络-逐渐和/或突然改变了配置，在数千年至数百万年的时间尺度上增长，缩小，甚至消失。河流网络的重组已经保持了神秘的斯台普斯景观在大陆内部超过世纪。当远离任何活跃的地质断层时，人们对触发它们的原因、它们启动的频率或它们演化的速度知之甚少。在这个项目中，首席研究员将评估河流出口附近的抗性岩石触发和调节大陆内部广泛的河流网络重组的假设。由于人类社会依赖水来发展和繁荣，因此限制河流过去、当前和未来分布的潜在调节因素对于了解地球表面和地下水资源的可用性和可持续性至关重要。通过这个项目的发现，首席研究员将创建一个沉浸式的，协作的教学计划，以培养一个多元化的本科生和研究生群体的主题和技术的高环境相关性。这项工作将促进科学知识在美国、巴西的高等教育中的整合，以及在纽约大都会地区的合作高中中的整合。尽管处于构造死亡的环境中，大陆内部的景观充满了排水网络重组和持续地形变化的证据。目前，没有统一的机制系统地解释了空间分布，规模，模式和时间的排水分水岭迁移和河流捕获事件在这些景观。该研究项目将从机制上将（i）流域分水岭迁移率和（ii）河流捕获事件的频率-幅度与下游数百公里的岩性变化联系起来。首席研究员的研究小组将（i）使用宇宙成因核素限制巴西东南部构造死亡的巴拉那盆地东部大型相邻流域之间的流域面积交换率，（ii）将这些比率与岩石性质的盆地对差异直接联系起来（即岩石的可蚀性、抗拉强度和抗压强度），以及（iii）利用Landlab库将经验证据与景观演变的数值模拟相结合。使用这个综合的现场+实验室+数值模拟三位一体，研究结果将系统地解释独立于外部，难以约束的触发器的大陆内部排水重组率。该项目还将通过定量地貌学的无障碍，脚手架培训机会，在科学发现和本科教育之间创建一个无缝的门户。该奖项反映了NSF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。

Though seemingly static to humans, watersheds – and the river networks they host – gradually and/or abruptly change configuration, growing, shrinking, and even disappearing over timescales of thousands to millions of years. River network reorganizations have remained enigmatic staples of landscapes in the interiors of continents for over a century. When far from any active geologic faults, little is known about what triggers them, how frequently they initiate, or how fast they evolve. In this project, the principal investigator will evaluate the hypothesis that resistant rocks near the outlets of rivers trigger and regulate the widespread river network reorganization in continent interiors. As human societies depend on water to develop and thrive, constraining the underlying regulators of past, current, and future distributions of rivers is fundamental to understanding the availability and sustainability of water resources on the Earth’s surface and subsurface. Through this project’s discoveries, the principal investigator will create an immersive, collaborative teaching initiative to train a diverse group of undergraduate and graduate students in topics and techniques of high environmental relevance. The work will foster the integration of scientific knowledge in higher education in the US, Brazil, and in collaborating high schools of the New York Metro area.Despite being in tectonically dead settings, landscapes in continent interiors are rife with evidence of drainage network reorganization and ongoing topographic change. Currently, no unifying mechanism systematically explains the spatial distribution, magnitudes, modes, and timing of drainage divide migration and river capture events in those landscapes. This research project will mechanistically link (i) rates of drainage divide migration and (ii) frequency-magnitudes of river capture events to lithologic changes of up to hundreds of kilometers downstream. The principal investigator’s research group will (i) constrain drainage area exchange rates between large neighboring drainage basins of the tectonically dead eastern Paraná Basin in southeast Brazil using cosmogenic nuclides, (ii) directly link those rates to basin-pair differences in rock properties (i.e. rock erodibilities, tensile, and compressive strengths), and (iii) integrate the empirical evidence with numerical modeling of landscape evolution using the Landlab library. Using this integrated Field + Laboratory + Numerical Modeling triad, the research results will systematically explain rates of drainage reorganization in continent interiors independent of external, hard-to-constrain triggers. Τhe project will also create a seamless doorway between scientific discovery and undergraduate education through accessible, scaffolded training opportunities in Quantitative Geomorphology. The activities will inspire and empower the participating, underrepresented student populations to tackle environmental challenges.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.