Collaborative Research: Testing competing models for the origin and magma transport dynamics of the Columbia River LIP

合作研究：测试哥伦比亚河 LIP 的起源和岩浆输送动力学的竞争模型

• 批准号: 1946292
• 负责人: Martin Streck
• 金额: $ 32.58万
• 依托单位: Portland State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-02-15 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946292&HistoricalAwards=false
• 关键词: Collaborative; Research; Testing; competing; models

The Pacific Northwest of the United States is an area that has been impacted by volcanic eruptions for millions of years. Particularly notable are the many huge eruptions that produced the Columbia River Basalts (CRB) between 17 and 6 million years ago. The CRB lavas inundated Oregon and Washington, producing thick stacks of lava, in places of thousands of feet or more, and covering in excess of 150,000 square miles. Such voluminous lava outpourings are Earth’s biggest volcanic events and understanding them is key to understanding fundamental aspects of the dynamic behavior of our planet. Lavas of the CRB were fed from fissure eruptions similar to those observed today on Hawaii, Iceland, or at other areas with active basalt volcanism, but much much larger in scale. In recent years, it has become clear the magmas feeding such events can travel long distances laterally underground, instead of vertically from an underlying melt source prior to their eruption. This study will address whether CRB magmas travelled in the subsurface for long distances, and where the magma storage sites were located, to better understand where magmas from the deep Earth interior ( 40 km) ascended to the surface.This study will combine geochronological, geochemical, and rock magnetic techniques to examine magma flow within Columbia River feeder dikes, and thus will test models of magma transport. Along-strike variations in the age, chemistry, and flow direction in the ~400 km-long Columbia River dike system will be examined to constrain regional-scale magma transport dynamics in the plumbing system of this Large Igneous Province (LIP). This multidisciplinary approach will provide the first dataset of magnetic flow for Columbia River LIP dikes and to supply new and critical constraints on the timing and dynamics of magma emplacement in the province, which are currently lacking. Key questions related to Columbia River LIP magmatism that can be addressed with the new data include: 1) Did Columbia River LIP magmas originate from the inferred inception position of the Yellowstone hotspot at the Nevada-Oregon border? 2) Were there discrete zones of magma storage, from which magma travelled laterally away to feed flood lavas? 3) Over what timescales were dike swarms emplaced, and did the site of magmatism progressively migrate northward away from the Yellowstone hotspot? This project will support graduate and undergraduate students at two institutions, and build an international collaboration with faculty and students at the University of Auckland, NZ. The PI team will also run field workshops for local high school teachers in both Oregon and Washington.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.

美国西北太平洋地区是一个数百万年来一直受到火山爆发影响的地区。特别值得注意的是1700万至600万年前产生哥伦比亚河玄武岩（CRB）的许多巨大喷发。CRB熔岩淹没了俄勒冈州和华盛顿，在数千英尺或更高的地方产生了厚厚的熔岩，覆盖了超过15万平方英里。如此大量的熔岩喷发是地球上最大的火山事件，了解它们是了解我们星球动态行为的基本方面的关键。CRB的熔岩来自裂缝喷发，类似于今天在夏威夷、冰岛或其他活跃的玄武岩火山活动地区观察到的，但规模要大得多。近年来，人们已经清楚地看到，这些事件的岩浆可以在地下横向移动很长的距离，而不是在喷发前从下面的熔体源垂直移动。这项研究将解决是否CRB岩浆在地下旅行了很长一段距离，岩浆储存地点的位置，以更好地了解岩浆从地球深部内部（40公里）上升到surface.This研究将联合收割机地质年代学，地球化学和岩石磁学技术来检查岩浆流内哥伦比亚河馈线堤防，从而将测试模型的岩浆运输。沿走向变化的年龄，化学成分和流动方向的约400公里长的哥伦比亚河堤防系统将被检查，以限制区域规模的岩浆运输动力学的管道系统的大火成岩省（LIP）。这种多学科的方法将提供第一个数据集的磁流哥伦比亚河LIP堤防，并提供新的和关键的限制岩浆侵位的时间和动力学在该省，这是目前缺乏的。与哥伦比亚河LIP岩浆活动相关的关键问题可以用新数据来解决，包括：1）哥伦比亚河LIP岩浆是否起源于内华达州-俄勒冈州边界黄石热点的推断起始位置？2)是否存在岩浆储存的离散区域，岩浆从这些区域横向移动，供给泛滥熔岩？3)岩墙群在什么样的时间尺度上就位，岩浆活动的地点是否逐渐向北迁移远离黄石热点？该项目将支持两个机构的研究生和本科生，并与新西兰奥克兰大学的教师和学生建立国际合作。PI团队还将在俄勒冈州和华盛顿为当地高中教师举办实地研讨会。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。