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

合作研究：宇宙成因核素年代学和晚更新世米苏拉洪水的古水力模型

• 批准号: 1530097
• 负责人: Peter Clark
• 金额: $ 2.52万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-01 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1530097&HistoricalAwards=false
• 关键词: Collaborative; Research; Cosmogenic; nuclide; chronology

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.

对该项目的非技术描述，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般的斯卡兰是地质学的壮观地标。它们形成于最后一个冰河时代末期，当时米苏拉冰川湖决堤，一场灾难性的洪水在流入哥伦比亚河的过程中雕刻了这片景观。最近的调查显示，有不止一次的洪水事件；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紧密的约束。然后，该项目将利用这些结果结合水力模型来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弱势群体的女博士生的教育。通过确定该地区景观发展的年代，新的采样地点战略性地定位于解决与洪水历史相关的一些具体问题，这些问题可以通过提议的建模情景进行评估，包括：(1)与多次洪水相比，有多少景观是一次大洪水减弱阶段的产物？(2)冰川前进和后退的时间与洪水事件的年代有何关系？(3)目前所有的洪水景观是否都与密苏拉冰湖的排水有关？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源区。为了评估这些预期结果的意义，一个模型将计算由邻近冰盖的冰川均衡调整引起的时变地形，然后使用一个水力模型来解决自由表面流动的完整二维、深度平均动量和连续性方程。