Collaborative Research: Identifying Sediment Sources and Routing of Transcontinental Drainages During Intraplate Deformation

合作研究：识别板内变形过程中的沉积物来源和跨大陆排水系统的路线

• 批准号: 1742951
• 负责人: Jeffrey Rahl
• 金额: $ 9.89万
• 依托单位: Washington and Lee University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1742951&HistoricalAwards=false
• 关键词: Collaborative; Research; Identifying; Sediment; Sources

The largest rivers in the world often start in mountain ranges on one side of a continent and bring sediment to deltas on the opposite side of the continent. The factors that allow these long-lived rivers to maintain or re-establish their courses in the face of changing geological conditions are largely unexplored. This project will study how transcontinental rivers change with time in response to the formation of mountain ranges or basins in the rivers' pathways. Understanding how rivers respond: whether they find a way through or around the developing mountains or basins, and how quickly they re-establish their prior courses, is critical to accurately interpreting the sedimentary record in their deltas. In addition to providing greater insight into continental-scale rivers, this project will provide STEM training for graduate and undergraduate students and support research infrastructure and analytical facilities at a large state university and a small private university. Further, the project will provide an opportunity for hands-on STEM training for ~30 middle school students per year under the guidance of a university professor. Research will focus on the "Ancestral Rocky Mountains" (ARM) and associated basins, which developed primarily in Utah, Colorado, Texas, and New Mexico 320-280 million years ago. These basins archive changes associated with disruption and reintegration of a continental-scale river in response to ARM evolution. This project will combine traditional and cutting-edge methods including field observations of sedimentary strata, U-Pb radiometric dating, analysis of Hf isotopes, and (U-Th)/He radiometric dating of zircons and monazite minerals in sandstones and igneous rocks to determine where sediment came from and how it changed through time. In addition, (U-Th)/He radiometric dating on zircon minerals in igneous rocks will be used to determine when the mountain ranges developed. These data will link changes in sediment sources to mountain and basin development through time. This will be augmented by development of new software to help determine the sources, and proportion of each source, for sediment based on radiometric dating of minerals in sandstones.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.

世界上最大的河流往往起源于大陆一侧的山脉，并将沉积物带到大陆另一侧的三角洲。 使这些长寿的河流能够在不断变化的地质条件下保持或重建其河道的因素在很大程度上尚未探索。 该项目将研究横贯大陆的河流如何随着时间的推移而变化，以应对河流路径中山脉或盆地的形成。 了解河流如何回应：它们是否能穿过或绕过正在形成的山脉或盆地，以及它们能多快地重新建立它们先前的路线，对于准确地解释它们三角洲的沉积记录至关重要。 除了提供对大陆规模河流的更深入了解外，该项目还将为研究生和本科生提供STEM培训，并支持大型州立大学和小型私立大学的研究基础设施和分析设施。 此外，该项目将在一名大学教授的指导下，每年为约30名中学生提供动手STEM培训的机会。 研究将集中在“祖先落基山脉”（ARM）和相关的盆地，其中主要是在犹他州，科罗拉多，得克萨斯州和新墨西哥州3.2亿至2.8亿年前发展。 这些流域档案的变化与中断和重新整合的一个大陆规模的河流，以响应ARM的演变。 该项目将结合联合收割机传统的和先进的方法，包括沉积地层的实地观察，U-Pb放射性测年，Hf同位素分析，以及砂岩和火成岩中锆石和独居石矿物的（U-Th）/He放射性测年，以确定沉积物的来源及其随时间的变化。 此外，（U-Th）/He放射性测年的火成岩中的锆石矿物将被用来确定何时山脉的发展。 这些数据将把沉积物来源的变化与山区和盆地的长期发展联系起来。这将通过开发新的软件来增强，以帮助确定来源，以及每种来源的比例，沉积物的基础上放射性测年的矿物在砂岩中。这个奖项反映了NSF的法定使命，并已被认为是值得的支持，通过评估使用基金会的知识价值和更广泛的影响审查标准。