Collaborative Research: Tectonic Links, Magma Fluxes, and Single Mineral Geochemistry in Plutonic Systems From 5-30 km Depth, Cascades Core, Washington

合作研究：5-30千米深的深成岩系中的构造联系、岩浆流动和单矿物地球化学，华盛顿州喀斯喀兹岩芯。大陆岩浆弧是地幔岩浆大量增加的地方，这些岩浆有助于驱动地壳的熔融、增厚和重组。我们对白垩纪和更古老的大陆岩浆弧的大部分了解都来自于对深成岩的物理和化学研究，而派生数据强烈影响着地壳生长和演化的模型。与可以分析单个喷发单元的现代弧不同，深成岩记录了更丰富的历史，尽管复杂，并且比单独的火山岩记录的岩浆流量占总岩浆流量的比例要大得多。关键问题涉及中间成分岩浆如何以及以多大的速度通过地壳柱，以及地壳如何容纳这些潜在的大流量？回答这些问题的关键是了解大量结晶岩浆或深成岩浆和熔岩是如何构成的。为了解决这些问题，建议开展合作研究，以更好地了解弧下岩浆管道系统。该项目的重点是北喀斯喀兹大陆岩浆弧的根部，它由三个暴露良好的侵入体组成，侵入体位于地壳的不同深度。综合野外填图、构造分析、矿物地球化学、高精度地质年代学和耦合同位素研究将被用来[1]确定深成岩浆代表不同来源的单一岩浆批次或部分结晶岩浆的复杂混合物的程度，[2]估计熔体产生、迁移和喷发的岩浆通量速率和时间尺度，以及[3]评估区域构造应变和岩浆形成之间的潜在联系。这项多学科的合作研究有望为理解岩浆管道系统和大陆岩浆弧中深成岩的形成做出重大贡献。这项研究将支持麻省理工学院和南加州大学的博士生，至少两名上海州立大学的硕士研究生，以及所有四所院校的多名本科生助理。BPTH SJSU PIs已经监督了2个由他们最近的拨款支持的理工科研究项目，Paterson在南加州大学教授了一个正式的研究课程，有20名本科生参与了NSF支持的研究。来自上海州立大学和南加州大学的研究生将参观肯特在俄亥俄州立大学的实验室进行自己的分析，而麻省理工学院的研究生将访问上海州立大学并协助进行虾类分析。上海州立大学的四名硕士学生已经前往麻省理工学院，在皮博林和他的学生的指导下进行U-Pb测年，这种类型的互动预计将继续下去。所有的私人助理都会常规地将他们的研究纳入课堂讲课，并在实验室课程中使用研究样本。最重要的是，PI正在向一大批新生展示强烈的跨学科和协作工作的力量。

Collaborative Research: Tectonic links, magma fluxes, and single mineral geochemistry in plutonic systems from 5-30 km depth, Cascades core, WashingtonIntellectual Merit. Continental magmatic arcs are the site of massive additions of mantle derived magmas which serve to drive melting, thickening, and reorganization of the crust. Much of what we know about Cretaceous and older continental magmatic arcs results from studies of the physics and chemistry of plutonic rocks, and the derivative data strongly influence models of crustal growth and evolution. In contrast to modern arcs where single eruptive units may be analyzed, plutons record a much richer, albeit complex, history and represent a much greater percentage of the total magmatic flux than volcanic rocks alone. Critical questions concern how and at what rate intermediate composition magmas move through the crustal column, and how the crust accommodates these potentially large fluxes? Key to answering these questions is to understand how large masses of crystallized magmas or plutons and batholiths are constructed. To address these questions, collaborative research is proposed to better understand sub-arc magmatic plumbing systems. This project focuses on the roots of a continental magmatic arc in the North Cascades that comprises three well-exposed intrusive bodies emplaced at different depths in the crust. Integrated field mapping, structural analysis, mineral geochemistry, high-precision geochronology and coupled isotopic studies will be employed to [1] determine the degree to which plutons represent single magma batches or complex mixtures of partially crystallized magmas of different origins, [2] estimate magma flux rates and timescales for melt generation, transport, and eruption of intermediate composition magmas, and [3] evaluate potential linkages between regional tectonic strain and magma formation. This multidisciplinary collaborative research is expected to contribute significantly to understanding of magma plumbing systems and the formation of plutons in continental magmatic arcs.Broader Impacts. This research will support Ph.D. students at MIT and USC, and at least 2 M.S. students at SJSU, and multiple undergraduate student assistants at all 4 institutions. Bpth SJSU PIs have supervised 2 B.S. research projects supported by their most recent grants, and Paterson teaches a formal research class at USC that has involved 20 undergraduates in NSF-supported research. Graduate students from SJSU and USC will visit Kent's lab at OSU to conduct their own analyses, and the MIT graduate student will visit SJSU and assist in SHRIMP analyses. Four M.S. students at SJSU have gone to MIT to carry out U-Pb dating under the tutelage of PI Bowring and his students, and this type of interaction is expected to continue. All of the PIs routinely incorporate their research in class lectures and use research samples in lab courses. Most importantly, The PI's are demonstrating to a large cross section of new students the power of strongly interdisciplinary and collaborative work.