Collaborative Research: NSFGEO-NERC: Magnetotelluric imaging and geodynamical/geochemical investigations of plume-ridge interaction in the Galapagos

岩浆是如何从地幔流向地表的，人们知之甚少。它是缓慢地流过地幔，还是快速地流过富含融水的通道？回答这个问题将有助于了解海底火山形成的位置以及它们喷发的频率。该项目将在加拉帕戈斯群岛获取新的地球物理和地质数据。这个地区从主群岛一直到几百公里外的洋中脊都有火山活动。研究人员将把新的数据与理论模型结合起来，测试岩浆流动的不同模型。研究结果对留尼旺岛、亚速尔群岛、复活节岛以及全球俯冲带等其他地区也很重要。更广泛的影响包括支持和培训研究生和博士后学者，为早期职业科学家提供参与研究巡航的机会，与加拉帕戈斯群岛的查尔斯达尔文基金会合作，以及向公众和K-12学生提供服务。这是一个由美国国家科学基金会地球科学理事会（NSF/GEO）和英国国家环境研究委员会（NERC）通过NSF/GEO-NERC牵头机构协议共同资助的项目。该协议允许美国/英国提交一份联合提案，并由其调查员拥有最大比例预算的机构进行同行评审。在成功地共同确定一个奖项推荐后，每个机构资助预算的比例，以支持各自国家机构的科学家。提出的工作旨在通过综合多学科研究，显著提高对软流圈中熔体输送和熔体局部化过程的理解。作为一个案例研究，该项目将侧重于加拉帕戈斯群岛的地幔柱/洋中脊的相互作用，以神秘的沃尔夫-达尔文线条为例。建议的工作包括三个关键部分：(1)利用大地电磁数据集进行新的海洋电阻率成像，以成像熔体分布（部署90个海底宽带MT站点）；(2)加拉帕戈斯北部和西加拉帕戈斯扩张中心现有和新打捞样品的地球化学分析（主要元素和微量元素、挥发性含量、Sr、Nd、Pb和Fe同位素）；(3)建立两相熔体通道化的地球动力学模型，以约束熔体局部化的物理可行性。这些结果将综合起来产生一个新的全球羽脊相互作用和软流圈熔体输送的总体模式。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

How magma flows from the Earth’s mantle to the surface is poorly understood. Does it flow slowly through the mantle, or quickly through melt-rich channels? Answering this question will help understand where seafloor volcanoes form and how frequently they erupt. The project will acquire new geophysical and geological data in the Galapagos islands. This region has volcanism all the way from the main archipelago to the mid-ocean ridge a few hundred km away. The investigators will combine the new data with theoretical modeling to test different models for magma flow. The results will be important for other locations such as Reunion Island, Azores Islands, and Easter Island as well as global subduction zones. Broader impacts include support and training of a graduate student and postdoctoral scholar, opportunities for early career scientists to participate in the research cruise, collaboration with the Charles Darwin Foundation in Galapagos, and outreach to the public and K-12 students. This is a project jointly funded by the National Science Foundation’s Directorate for Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award recommendation, each Agency funds the proportion of the budget that supports scientists at institutions in their respective countries.The proposed works aims to significantly improve the understanding of melt transport in the asthenosphere, and melt localization processes, through an integrated multidisciplinary study. As a case study, the project will focus upon mantle plume/mid-ocean ridge interaction in the Galapagos which is exemplified by the enigmatic Wolf-Darwin Lineament. The proposed work includes three key components: (1) New marine resistivity imaging using magnetotelluric data sets for imaging melt distribution (with deployment of 90 ocean bottom broadband MT sites); (2) Geochemical analysis (major and trace elements, volatile content, Sr, Nd, Pb and Fe isotopes) of existing and new dredge samples along the northern Galapagos lineaments and Western Galapagos Spreading Center; and (3) Geodynamical modeling of two-phase melt channelization to constrain the physical viability of melt localization. These results will be integrated to generate a new global model for plume-ridge interaction and asthenospheric melt transport in general.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.