Origin of the Columbia River Basalts and Uplift of the Wallowa Mountains

黄石热点大约起源于16.5亿年前，当时集中在俄勒冈州东北部的玄武岩洪水喷发。这一事件的起源尚不清楚，它对岩石圈的总体影响也不清楚。这项研究将帮助我们了解黄石热点是如何开始的，以及大陆岩石圈内的过程。一些观测结果似乎与羽流假说不一致：没有爆发前的隆起，岩浆裂缝发生在一个狭窄但长达700公里的区域，岩浆活动的主要焦点发生在远离当前黄石热点轨道的地方。这是一个特别适合进行这项研究的地点；没有其他任何地方有这么大的、暴露良好的、年轻的、可进入的大陆生长区域。研究人员将在瓦洛瓦地区部署25个站的远震站，与USArray的部署相协调，对俄勒冈州东北部及附近地区的基本地壳和上地幔结构进行成像。这是最大的玄武岩喷发发生的地区，也是在这里见证了一次显著的隆起事件，形成了一个以瓦洛瓦岩体为中心的牛眼状浮雕。地震调查将通过一组集中的地球动力学模型来增强，以一种在现实流变行为约束下强制质量和热量守恒以及力平衡的方式来测试一系列假设。本提案的研究计划旨在改进用于理解地球过程的方法，通过使用地球动力学计算机模型来定量关联假设和一系列观测，并通过在岩石圈尺度分辨率的国家阵列（USArray）中嵌入地壳尺度分辨率的远震阵列来研究一个区域。该项目将通过合作、参与不同学科、将一系列研究结果整合为一致的结果，为学生和博士后的未来做好准备。

The Yellowstone hotspot initiated about 16.5 m.y. ago with a flood basalt eruption concentrated in NE Oregon. The origin of this event is not clear, nor is its overall effect on the lithosphere. This study will help us to understand how the Yellowstone hotspot began and the processes within the continental lithospheric. Several observations seem inconsistent with the plume hypothesis: there was no pre-eruptive uplift, magmatic fissuring occurred from a narrow but 700 km-long zone, and the main focus of magmatism occurred far off of the current Yellowstone hotspot track. This is a particularly suitable location for this study; nowhere else is there such a large, well-exposed, young and accessible area of continental growth interior to the continent. The investigators will deploy 25-station teleseismic stations coordinated with the USArray deployment in the Wallowa area to image basic crustal and upper mantle structure in NE Oregon and nearby regions. This is the region from which the greatest basalt eruption occurred, and it is that which witnessed a remarkable uplift event that created a bull's eye pattern of relief with the Wallowa pluton at its center. The seismic investigation will be augmented with a focused set of geodynamic models to test a range of hypotheses in a manner that enforces mass and heat conservation and force balance under the constraints of realistic rheologic behavior.The research plan of this proposal is designed to improve on the methods used to understand Earth processes by using geodynamic computer models to quantitatively relate hypotheses and a range of observations, and by studying a region with a teleseismic array of crustal-scale resolution embedded within a national array (USArray) of lithospheric-scale resolution. This project will prepare students and post-docs for the future through collaborations, participation in a diverse set of disciplines, and integration of the range of findings into consistent results.