Collaborative Research: Cosmogenic nuclide chronology and paleohydraulic modeling of late Pleistocene Missoula floods

对该项目的非技术性描述，解释了该项目的意义和重要性华盛顿州和俄勒冈州的沟渠地带是壮观的地质学地标。它们是在上一个冰河时代结束时形成的，当时冰川密苏拉湖的大坝决口，一场灾难性的洪水冲刷了这片土地，洪水流入哥伦比亚河。最近的调查表明，洪水事件不止一次；该项目将使用新的测年技术，对洪水事件的年龄和数量提供更密切的限制。然后，该项目将结合水力学模型使用这些结果来评估这些洪水事件的大小和持续时间以及对景观的影响。这一结果可以用来研究大洪水对世界其他地区地形的影响。该项目将支持来自代表性不足群体的女性博士生的教育。项目的技术描述通过确定该地区的景观发育年龄，新的采样点具有战略意义地定位，以解决与洪水历史有关的一些具体问题，这些问题可以通过拟议的建模情景进行评估，包括：(1)有多少景观是一次大洪水的退潮阶段与多个年龄段洪水的产物？(2)冰的进退时间与洪水事件的年龄有何关系？(3)目前的洪水景观是否都与冰川湖米苏拉湖的排水有关？这一新的地质年代学将指示不同年代的晚更新世大洪水所采取的各种不同的流动路径，不同流动事件的不同淹没程度，甚至可能是产生流动的不同源区。为了评估这些预期结果的影响，一个模型将计算来自邻近冰盖的冰川均衡调整产生的随时间变化的地形，然后使用一个水力模型，该模型求解自由表面流动的全二维、深度平均的动量和连续性方程。

A non-technical description of the project, which explains the project's significance and importanceThe Channeled Scablands of Washington and Oregon are spectacular landmarks of geology. They were formed at the end of the last ice age when Glacial Lake Missoula breached its dam and a catastrophic flood carved the landscape as the water made its way to the Columbia River. Recent investigations have shown there was more than one flood episode; this project will use new dating techniques to provide a closer constraint on the ages and number of flood events. The project will then use these results in conjunction with a hydraulic model to evaluate the size and duration of these flood events and the effects on the landscape. The results could be used to examine the impact of large floods on topography in other parts of the world. The project will support the education of a female PhD student from an underrepresented group.A technical description of the projectBy establishing the age of landscape development in this region, the new sampling sites strategically located to address a number of specific questions related to flood history that can be assessed with the proposed modeling scenarios, including: (1) How much of the landscape is the product of waning stages of one large flood versus of multiple-age floods? (2) How does the timing of advance and retreat the ice relate to ages of flood events? (3) Are all present flood landscapes related to the draining of glacial Lake Missoula? This new geochronology will indicate a variety of different flow paths taken by different-aged late Pleistocene mega-floods, different inundation levels for various flow events, and possibly even different source regions for generating the flows. To evaluate the implications of these anticipated results, a model will calculate time-varying topography resulting from glacial isostatic adjustment from the adjacent ice sheet, and then use a hydraulic model which solves the full two-dimensional, depth-averaged momentum and continuity equations for free-surface flow.