Collaborative Research: Origin of Crust and the Temporal and Spatial Scales of Mantle Melting at the Endeavour Segment, Juan de Fuca Ridge

摘要0623161/0623255/0623156（吉尔/迈克尔/拉莫斯）学术成就：这项研究考察了洋壳是如何在中速洋中脊扩张中心形成的，熔体和热液系统在这种环境中是如何相互作用的，以及火山和热液喷口与它们下面的地幔熔体在时间和空间上的关系。 将综合地球物理、地质和地球化学数据，以全面了解该系统。 已收集的胡安德富卡扩张脊海底火山岩的主要和微量元素化学以及相应的放射性同位素、挥发物含量和U系列元素构成地球化学数据集的核心。 调查的目标是：测试在海底扩张期间地幔铅垂移动时，洋壳2A层是否形成离轴，并评估反映岩浆成分和脱气不均匀性的海底喷发玄武岩的不均匀性是否与上覆热液系统的成分和强度变化有关。这项工作促进了华盛顿州、加州和俄克拉荷马州的学术机构和科学家之间的合作。 影响包括支持早期职业科学家和支持国家科学基金会资助的RIDGE 2000计划的目标。 研究生和本科生将接受最先进的分析技术培训，这项工作支持在中央华盛顿大学建立U系列分析实验室，扩大其研究基础设施。将通过RIDGE 2000教育和外联办公室向K-12教师及其学生开展公共外联活动。

ABSTRACT 0623161/0623255/0623156 (Gill/Michael/Ramos)Intellectual Merit: This research examines how ocean crust is formed at intermediate rate mid-ocean ridge spreading centers, how melts and hydrothermal systems interact in this setting, and at what scale in time and space the volcanics and hydrothermal vents relate to mantle melts beneath them. Geophysical, geological, and geochemical data will be integrated to obtain a holistic picture of the system. Major and trace element chemistry of already collected seafloor volcanic rocks from the Juan de Fuca spreading ridge, as well as corresponding radiogenic isotopes, volatile contents, and U-series elements form the core of the geochemical data set. Objectives under investigation are: testing whether layer 2A of the ocean crust forms off-axis as mantle plumbing moves during seafloor spreading and evaluating whether heterogeneities in basalts, that are erupted on the seafloor that reflect heterogeneities in magma composition and degassing, can be tied to variations in the composition and intensity of the overlying hydrothermal systems.Broader Impacts: The work fosters collaboration between academic institutions and scientists in Washington state, California, and Oklahoma. Impacts include support of an early career scientist and support the objectives of the NSF-funded RIDGE2000 Program. Graduate and undergraduate students will be trained in state-of-the-art analytical techniques, and the work supports the set-up of a U-series analytical laboratory at Central Washington University expanding its infrastructure for research. Public outreach to K-12 teachers and their students will be carried out through the RIDGE2000 Education and Outreach Office.