Collaborative Research: Synthesizing arc-scale geochemical, petrologic, and geophysical datasets to investigate causes of volcanic diversity in the Cascade Arc

俯冲带——地球的一个板块被推到另一个板块下方的位置——是地球上火山最活跃的环境之一。几十年来对俯冲带的研究已经深入了解了产生岩浆喷发的总体过程、单个火山如何产生喷发的岩浆以及许多相关问题。尽管取得了这些进展，但一个复杂且基本上尚未解决的问题是导致同一俯冲带内火山喷发的岩浆数量和成分普遍存在巨大变化的原因。这些是否反映了地幔深处或上覆地壳中作用的过程？解决这个问题对于了解岩浆的产生和火山危害具有重要意义，因为全世界有近十亿人生活在火山的危险之中。利用 NSF 近期投资（例如 MARGINS、GeoPRISMS 和 EarthScope 计划）获得的现有大型数据集，也有可能实现科学突破。然而，迄今为止，解决这个问题已被证明具有挑战性，部分原因是某些地点缺乏关键数据，但很大程度上是因为缺乏合适的工具和方法，使我们能够定量综合和比较现有的大型数据集。因此，这是一项多学科研究，旨在对整个喀斯喀特俯冲带空间尺度上的现有大型地球物理和成分数据集进行定量比较，通过热量和密度等常见的密集变量集联系起来，以确定弧内岩浆多样性的主要驱动因素。该项目以成功的概念验证项目为基础，展示了该方法的前景（Till 等，2019），该项目将测试有关地幔岩浆通量与地壳特征和地壳岩浆储存深度在产生喷发成分和通量变化以及控制第四纪喀斯喀特弧沿走向的地壳地球物理状态方面的相对作用的假设。该项目有潜力改变我们对这些重要区域的理解，并将产生许多重要的更广泛的影响，包括促进三个机构的三个 PI 之间的跨学科合作，为地球科学界广泛且轻松地提供专家数据集，支持本科生体验式学习活动。具体来说，它将与来自亚利桑那州立大学、俄勒冈州立大学和康奈尔大学的研究团队实施一项新的多年本科研究计划 CONVEcT 计划（中央俄勒冈火山教育和培训网络）。该奖项反映了 NSF 的法定使命，并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，被认为值得支持。

Subduction zones – locations where one of the Earth’s tectonic plates are pushed beneath another – are one of the most volcanically active environments on the planet. Decades of study on subduction zones have provided insight into the overarching processes that produce the magmas erupted, how the erupted magmas are produced at individual volcanoes, and a number of related questions. Despite this progress, a complex and largely unsolved problem is the cause of ubiquitous and dramatic variations in the amount and composition of magmas that erupt at volcanoes within the same subduction zone. Do these reflect processes acting deep within the Earth’s mantle, or in the overlying crust? Addressing this problem has important implications for understanding magma production and volcanic hazards, as worldwide almost a billion people live at risk from volcanoes. There is also a potential for scientific breakthrough by utilizing the existing large data sets acquired from recent NSF investments such as the MARGINS, GeoPRISMS, and EarthScope programs. However, addressing the question has proven challenging to date in part because of a lack of critical data for some locations, but largely because of the lack of suitable tools and approaches that allow us to quantitatively synthesize and compare the existing large data sets. Thus, this is a multidisciplinary study to conduct a quantitative comparison of existing large geophysical and compositional datasets at the spatial scales of the entire Cascades subduction zone, linked through sets of common intensive variables such as heat and density, to determine the primary drivers of intra-arc magmatic diversity. Building on a successful Proof of Concept project that demonstrates the promise of the approach (Till et al., 2019), the project will test hypotheses about the relative roles of mantle magmatic flux vs. crustal characteristics and crustal magma storage depths in producing variations in erupted compositions and fluxes, and in controlling the geophysical state of the crust along strike in the Quaternary Cascades arc. The project has the potential to transform our understanding of these important regions and will produce a number of important broader impacts including, catalyzing interdisciplinary collaborations between three PI’s at three institutions, producing expert datasets widely and easily available to the Earth Science community, supporting undergraduate experiential learning activities. Specifically, it will implement a new multi-year undergraduate research program CONVEcT program (Central Oregon Network for Volcano Education and Training) with research cohorts from Arizona State, Oregon State and Cornell Universities.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.