The birth of longitudinal rivers in orogenic systems

山脉地带的大型水系对侵蚀、向海洋输送泥沙以及物种的分布和演变起着重要的控制作用。这些河流是高度流动的系统，了解调节其发展和演变的过程是地球表面过程中的基本问题。该提案将通过研究由这些河流输送的现代和古代沉积物，解决导致哥伦比亚北部安第斯山脉主要纵向河流系统增长的时机和因素。该项目的数据将为俄克拉荷马大学的一门新课程奠定基础。练习旨在向学生介绍可转移的技能，包括基本的编码、绘图和地理空间软件的使用。这些练习将在网上提供(免费)，供其他人在教学或研究中使用或修改。此外，该项目将支持和培训本科生和研究生以及一名博士后学者，并继续加强与国际科学家的合作。更具体地说，这项提案将结合现代地貌学、来源特征和盆地分析，解决安第斯山脉北部马格达莱纳河和考卡河的增长问题。地貌指数将被用来识别现代排水不稳定的区域，10Be侵蚀率将允许评估显著交界点的侵蚀率沿走向的变化。三个次平行山脉(西部、中部和东部科迪勒拉斯)的独特沉淀物来源有助于利用来源追踪排水网络随时间的变化。这些独特的沉积物源区将使用现代河沙上的物源代理来表征。上中新世-上新世地层也将获得物源记录。在感兴趣的沉积区间中互层的火山和火山碎屑物质将使强大的年代地层学得以发展。改进的年代地层框架和新的物源数据集将使人们能够识别随着时间的推移水系网络的上游变化。现代地貌指标和物源记录的结合将检验构造分流导致安第斯山脉北部纵向河流诞生的基本假设。样本的子集将成为一系列教学模块的基础，这些模块将作为教学工具公开提供给更广泛的地球科学界。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。

Large river systems in mountain belts exert important controls on erosion, sediment flux to oceans, as well as the distribution and evolution, of species. These rivers are highly mobile systems and understanding the processes that modulate their development and evolution are fundamental questions in earth surface processes. This proposal will address the timing and factors that caused the growth of major longitudinal river systems in the northern Andes Mountains of Colombia by studying the modern and ancient sediment transported by these rivers. Data from this project will form the foundation for a new course at the University of Oklahoma. Exercises will be designed to introduce students to transferable skills including basic coding, plotting, and use of geospatial software. These exercises will be available online (at no charge) for others to use or modify in teaching or research. Additionally, this project will support and train undergraduate and graduate students and a postdoctoral scholar, and continue to enhance collaborations with international scientists. More specifically, this proposal will address growth of the Magdalena and Cauca Rivers in the northern Andes Mountains using combination of modern geomorphology, source characterization, and basin analysis. Geomorphic indices will be used to identify areas of modern drainage instability, and 10Be erosion rates will allow for assessment of along-strike variations of erosion rates over notable knick-points. Unique sediment sources in three sub-parallel mountain ranges (Western, Central, and Eastern Cordilleras) facilitate the use of provenance to track shifts in drainage networks through time. These distinctive sediment source regions will be characterized using provenance proxies on modern river sands. Provenance records will also be obtained in upper Miocene-Pliocene strata. Interbedded volcanic and volcaniclastic materials in the sedimentary intervals of interest will enable development of a robust chronostratigraphy. The refined chronostratigraphic framework and new provenance datasets will allow identification of upstream shifts in drainage networks through time. Integration of modern geomorphic proxies and provenance records will test the principal hypothesis that structural diversion led to the birth of longitudinal rivers in the northern Andes. A subset of the samples will be the basis for a series of teaching modules, which will be publicly available to the broader geoscience community as teaching tools.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.