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。华盛顿和俄勒冈州的伤疤是地质学上壮观的地标。它们形成于上一个冰河时代末期，当时米苏拉冰川湖决堤，洪水涌入哥伦比亚河，造成了巨大的破坏。最近的调查表明，有一个以上的洪水事件，该项目将使用新的测年技术，以提供一个更密切的限制洪水事件的年龄和数量。然后，该项目将使用这些结果与水力模型相结合，以评估这些洪水事件的规模和持续时间以及对景观的影响。研究结果可用于研究大洪水对世界其他地区地形的影响。该项目将支持一名来自代表性不足群体的女博士生的教育。项目的技术说明通过确定该地区景观发展的年龄，新的采样点的位置具有战略意义，以解决与洪水历史相关的一些具体问题，这些问题可以通过拟议的建模方案进行评估，包括：（1）有多少景观是一次大洪水的衰退阶段的产物，而不是多次洪水的产物？(2)冰川进退的时间与洪水事件的年代有何关系？(3)所有目前的洪水景观都与冰川湖米苏拉的排水有关吗？这种新的地质年代学将表明不同年龄的晚更新世特大洪水所采取的各种不同的流动路径，各种流动事件的不同淹没水平，甚至可能是产生流动的不同来源地区。为了评估这些预期结果的影响，一个模型将计算随时间变化的地形，从邻近的冰盖冰川均衡调整，然后使用水力模型，解决了完整的二维，深度平均动量和连续性方程的自由表面流。

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.