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

摘要/ ABSTRACT摘要：0623161/0623255/0623156 （Gill/Michael/Ramos）学术成果：本研究探讨了洋中脊扩张中心的中速洋壳如何形成，熔融体与热液系统如何在此背景下相互作用，以及火山和热液喷口与其下地幔熔融在何种时间和空间尺度上的关系。地球物理、地质和地球化学数据将被整合，以获得该系统的整体图像。Juan de Fuca扩张脊已采集的海底火山岩主微量元素化学以及相应的放射性成因同位素、挥发性含量和u系列元素构成了地球化学数据集的核心。研究的目的是：测试海底扩张过程中地幔管道移动时，海洋地壳的2A层是否形成离轴，评估海底喷发的玄武岩的非均质性是否与上覆热液系统的组成和强度变化有关，这些玄武岩反映了岩浆组成和脱气的非均质性。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。影响包括支持早期职业科学家和支持nsf资助的RIDGE2000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，这项工作将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。对K-12教师和学生的公众宣传将通过RIDGE2000教育和外展办公室进行。

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.