Collaborative Research: A multidisciplinary study of hotspot - ridge interaction in the Easter microplate - Salas y Gomez system

合作研究：复活节微板 - Salas y Gomez 系统中热点 - 脊相互作用的多学科研究

• 批准号: 0752669
• 负责人: Richard Kingsley
• 金额: $ 9.5万
• 依托单位: University of Rhode Island
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-03-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0752669&HistoricalAwards=false
• 关键词: Collaborative; Research; multidisciplinary; study; hotspot

OCE-0752478, OCE-0752669Intellectual Merit: A substantial number of hotspots (concentrations of seafloor volcanoes that are believed to be associated with upwelling plumes of magma from the Earth's mantle) that are located within the interiors of oceanic plates (e.g., Kerguelen, Reunion, Galapagos) appear to directly influence the chemistry of the basalts found at mid-ocean ridges located at the boundaries of the plate, as evidenced by similarities in the chemistry of basalts produced at the hotspot and the proximal portion of the ridge, and anomalous crustal thickness along the ridge. However, the pattern of flow in the upper mantle that would allow such interaction remains poorly understood. This project will characterize mantle flow and melting in off-axis hotspot - ridge systems using a multidisciplinary modeling approach in which melting models are coupled to numerical geodynamic models to allow prediction of melt chemistry. The resulting coupled model will be applied particularly to the Easter - Salas y Gomez Seamount Chain (ESC) - Easter Microplate (EMP) system, with synthetic melt compositions used along with model-predicted geophysical parameters (e.g., crustal thickness, gravity) to constrain mantle flow through direct comparison to observational data. The ESC-EMP system is an ideal natural laboratory for studying interaction between a hotspot and a nearby mid-ocean ridge: the geometry of the ESC-EMP system is simple, there is recent volcanism along the portion of the ESC between the hotspot and the spreading center, and a comprehensive geochemical database for the region already exists. The project consists of two primary tasks. The first task is to model the existing geochemical data to constrain source and melting parameters relevant to the ESC-EMP system. These results will then be incorporated into a 3-D geodynamic model of hotspot-ridge systems to examine mantle flow in the ESC-EMP system. Geodynamic model predictions (e.g., spatial variations in melt chemistry, crustal thickness, gravity) will then be compared to observational data to constrain the temperature and composition of the Easter-Salas y Gomez hotspot as well as the manner in which material flows from the hotspot to the ridge axis (i.e., radial dispersion vs. channeled flow) . As a byproduct of the geodynamic modeling exercise, a series of 3-D benchmark tests relevant to mantle flow will be developed and applied to two numerical modeling packagesBroader Impacts: The inherently cross-disciplinary approach outlined in this proposal, coupling geochemistry with geodynamic modeling, will contribute to the professional development of the Principal Investigators, who are both recent PhDs. The project will also provide funding for a Boston University graduate student, who, while advised by Hall, would interact extensively with Kingsley, presenting the student with an excellent opportunity to work at the interface between geodynamics and geochemistry from the very start of their career. Results of benchmarking of the models for free- and forced-convection scenarios relevant to the upper mantle will be made available to the community at large through publication and online documentation. Furthermore, the simpler benchmark scenarios will become an integral part of an advanced undergraduate/introductory graduate level course on computational fluid dynamics in the Earth sciences currently being developed by Hall, in conjunction with fellow BU professor Sergio Fagherazzi. In addition, Hall will use the results of the project as a case study highlighting a multidisciplinary approach to understanding the Earth's interior, in the undergraduate geodynamics course he will be teaching at BU. Finally, the algorithms developed to model melting and predict melt chemistry, as well as to post-process these results, will be made available to the community through a website hosted at BU and possibly also through the Computational Infrastructure for Geodynamics (CIG) program

OCE-0752478、OCE-0752669知识产权优点：位于大洋板块内部的大量热点（海底火山的集中，据信与地幔上涌的岩浆羽流有关）（例如，Kerguelen、Reunion、加拉帕戈斯）似乎直接影响了位于板块边界的大洋中脊上发现的玄武岩的化学成分，这一点可以从热点和海脊近端部分产生的玄武岩的化学成分相似性以及沿海脊沿着的异常地壳厚度得到证明。然而，上地幔中允许这种相互作用的流动模式仍然知之甚少。该项目将采用多学科建模方法，将熔融模型与数值地球动力学模型相结合，以预测熔融化学，描述离轴热点-脊系统中的地幔流动和熔融特征。由此产生的耦合模型将特别应用于复活节-萨拉斯-戈麦斯海山链（ESC）-复活节微板块（EMP）系统，其中使用合成熔体成分沿着模型预测的地球物理参数（例如，地壳厚度、重力），通过与观测数据的直接比较来约束地幔流动。ESC-EMP系统是研究热点和附近洋中脊之间相互作用的理想天然实验室：ESC-EMP系统的几何形状简单，热点和扩张中心之间的ESC部分沿着最近有火山活动，该地区已经存在全面的地球化学数据库。该项目包括两项主要任务。第一个任务是对现有的地球化学数据进行建模，以约束与ESC-EMP系统相关的源和熔融参数。这些结果将被纳入一个3-D的地球动力学模型的热点脊系统研究地幔流的ESC-EMP系统。地球动力学模型预测（例如，然后将熔融化学、地壳厚度、重力的空间变化）与观测数据进行比较，以限制Easter-Salasy Gomez热点的温度和成分以及物质从热点流向脊轴的方式（即，径向分散与通道流）。作为地球动力学建模工作的副产品，将开发一系列与地幔流相关的3-D基准测试，并将其应用于两个数值建模包。更广泛的影响：本提案中概述的固有的跨学科方法，将地球化学与地球动力学建模相结合，将有助于首席研究员的专业发展，他们都是最近的博士。该项目还将为波士顿大学的一名研究生提供资金，他在霍尔的建议下，将与金斯利进行广泛的互动，为学生提供一个极好的机会，从职业生涯的一开始就在地球动力学和地球化学之间的界面工作。与上地幔有关的自由对流和强迫对流情景的模型基准测试结果将通过出版物和在线文件向广大社区提供。此外，更简单的基准情景将成为一个先进的本科生/介绍性研究生水平的课程，计算流体动力学在地球科学目前正在开发的霍尔，与同事BU教授塞尔吉奥Fagherazzi。此外，霍尔将使用该项目的结果作为一个案例研究，突出了多学科的方法来了解地球的内部，在本科地球动力学课程，他将在BU教学。最后，为模拟熔融和预测熔融化学以及后处理这些结果而开发的算法将通过BU托管的网站以及可能的地球动力学计算基础设施（CIG）计划向社区提供