Collaborative Research: The role of water in the melting of oceanic mantle

摘要 0623238/ 0623208（Kelley/Hauri）智力优异。地幔熔融过程和熔岩的形成受H2O的强烈影响，但水在不同构造环境中的作用明显不同。 这项研究探讨了水在远离俯冲或羽流影响的正常洋中脊融化状态中的作用，以及在受俯冲影响的洋中脊中的作用。这些假设将通过已经掌握的大洋中脊和弧后盆地玄武岩玻璃的地球化学分析进行检验。这项研究将使用离子探针（西姆斯）开发挥发性物质（例如，H2O、CO2等）和微量元素的玻璃熔岩从两个海底扩张制度：正常的大洋中脊（东太平洋隆起）和四个弧后盆地之间的过渡脊和俯冲带系统（伍德拉克，N。斐济、马努斯和北方劳盆地）。利用这些数据，将利用MELTS建立一个H2O对正常洋中脊下融化过程影响的综合模型。 然后将在四个弧后盆地的框架内对该模型进行测试。结果最终将导致一个更清晰的模型，说明H2O如何影响地幔熔融过程，地幔温度和挥发物含量如何影响洋壳的组成和结构，以及H2O如何在整个地球上地幔中分布和传输。这项研究支持了罗得岛大学的一位早期职业女性PI，该大学位于EPSCoR州。 该项目还促进国家和国际合作，并支持一名研究生谁将获得独特的，动手分析和建模经验。暑期本科实习生也将通过NSF REU计划参与研究。 这项工作与国家科学基金会资助的RIDGE科学计划和目标兼容。

ABSRACT 0623238/ 0623208 (Kelley/Hauri)Intellectual Merit. The process of mantle melting and the generation of lavas are strongly influenced by H2O, but water plays apparently different roles depending on tectonic setting. This research addresses the role of water in the melting regime of a normal mid-ocean ridge far from the influence of subduction or plumes, as well as in ridges influenced by subduction. Hypotheses will be tested with geochemical analyses of mid-ocean ridge and back-arc basin basalt glasses that are already in-hand. This study will use the ion probe (SIMS) to develop high-spatial-resolution data sets of volatile (e.g., H2O, CO2, etc.) and trace elements for glasses from lavas from two seafloor spreading regimes: a normal mid-ocean ridge (East Pacific Rise) and four back-arc basins that transition between ridge and subduction zone systematics (the Woodlark, N. Fiji, Manus and Northern Lau basins). Using the data, a comprehensive model of the influence of H2O on the melting processes beneath normal mid-ocean ridges will be developed using MELTS. The model will then be tested within the framework of the four back-arc basins. Results ultimately should lead to a clearer model of how H2O influences the mantle melting process, how mantle temperature and volatile contents impact the composition and structure of the oceanic crust, and how H2O is distributed and transported throughout the earth's upper mantle.Broader Impacts. This research supports an early career female PI at the University of Rhode Island, which is in an EPSCoR state. The project also fosters national and international collaboration and supports one graduate student who will gain unique, hands-on analytical and modeling experience. Summer undergraduate interns will also be engaged in the research through an NSF REU program. The work is compatible with the NSF-funded RIDGE science plans and objectives.