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 (Gill/Michael/Ramos)智力成果：这项研究研究了洋壳如何在中速洋中脊扩张中心形成、熔体和热液系统如何在这种环境下相互作用，以及火山和热液喷口在时间和空间上与它们下方的地幔熔体相关。 地球物理、地质和地球化学数据将被整合以获得系统的整体情况。 已收集的胡安德富卡扩张脊海底火山岩的主量和微量元素化学，以及相应的放射性同位素、挥发物含量和 U 系列元素构成了地球化学数据集的核心。 正在研究的目标是：测试海底扩张过程中地幔管道移动时洋壳第 2A 层是否形成离轴，并评估海底喷发的玄武岩的异质性（反映岩浆成分和脱气的异质性）是否与上覆热液系统的成分和强度的变化有关。更广泛的影响：这项工作促进了华盛顿州、加利福尼亚州和俄克拉荷马州的学术机构和科学家之间的合作。 影响包括对早期职业科学家的支持以及对 NSF 资助的 RIDGE2000 计划目标的支持。 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 RIDGE2000 教育和外展办公室对 K-12 教师及其学生进行公共外展。

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.