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)学术价值：这项研究考察了洋壳是如何以中等速度形成大洋中脊扩张中心的，在这种背景下熔岩和热液系统是如何相互作用的，以及火山和热液喷口在多大规模的时间和空间上与它们下面的地幔熔融有关。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景。已从胡安德·富卡扩张脊采集的海底火山岩的常量元素和微量元素化学，以及相应的放射性同位素、挥发分含量和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：测试在海底扩张过程中，当地幔管道移动时，洋壳的2A层是否偏离轴线形成，并评估在海底喷发的玄武岩中反映出岩浆成分和脱气不均质性的不均质性，是否与上面热液系统的组成和强度的变化有关。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何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。将通过RIDGE2000教育和外展办公室向K-12教师及其学生进行公众宣传。

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.