EAPSI:3-D Numerical Modeling of the 35-40E mid-ocean ridge segment along the Southwest Indian Ridge

大洋中脊是地球火山活动的一大部分，也是重大地震发生的地方。然而，大洋中脊只是更大的对流地幔系统的表面表达，人们对这种地幔知之甚少。该项目旨在解释地幔如何向地球表面提供物质，以及地幔如何在地表附近运动。地球动力学模拟是目前研究大洋中脊地幔过程和揭示那里的地质历史的唯一方法之一。地质观测使建模更加逼真。在这个项目中，将把从西南印度洋海脊采集的岩石的性质与许多模拟的岩浆成分进行比较，然后利用这些成分来寻找观测到的岩石来源下的地幔性质。这将使我们对海脊以及热点-海脊相互作用区有更好的了解。与东京大学冲野博士的团队合作，将允许利用新技术来追踪海脊的岩浆来源，并解释沿海脊轴线的不均一性。2007年和2009年，在西南印度洋海脊35-40度的一段区域收集了地幔衍生岩石和地球物理数据。这一段距离马里恩热点最近，与全球其他热点脊区不同，因为它经历了低岩浆流量，岩石的化学成分与其他热点脊区发现的岩石非常不同。COMSOL多物理将用于计算分段的物理属性。将使用Melts软件对地球化学示踪进行正演模拟，以推断源岩的几何形状、成分和熔融路径。使用MatLab对产生的模型的重力和磁场进行正演模拟，将使我们能够进一步限制地幔熔体的密度、深度和几何形状，从而更好地了解地幔系统作为一个整体。将地球化学和地球物理数据结合到模型中，代表了山脊模拟过程的根本进步，并将地球动力学模型与观测数据相结合。该NSF EAPSI奖是与日本科学促进会合作资助的。

Mid-ocean ridges are where a large part of the Earth's volcanism, and significant earthquakes occur. However, the mid-ocean ridges are just the surface expression of the larger convecting mantle system and this mantle is poorly understood. This project aims to explain how the mantle supplies material to the surface of the Earth, and how the mantle moves near the surface. Geodynamic modeling is one of the only ways that currently exists to investigate the mantle processes at mid-ocean ridges and to uncover the geologic history there. Geological observations make modeling more realistic. In this project, the properties of rocks collected from the Southwest Indian Ridge will be compared with many simulated magma compositions, which will then be used to find the properties of the mantle beneath the observed rocks' source. This will grant a better understanding of the ridges in general, as well as hotspot-ridge interaction zones. Collaboration with Dr. Okino's group at the University of Tokyo, will allow for the utilization of novel techniques in order to trace the magma source of the ridge and to explain heterogeneity along the ridge axis.In 2007 and 2009, 35-40 degrees segment of the Southwest Indian Ridge where mantle-derived rocks and geophysical data were collected. This segment is the nearest to the Marion hotspot and is anomalous from other hotspot-ridge regions around the globe in that it experiences a low magma flux, and the rocks have a very different chemical composition from rocks found at other hotspot-ridge regions. COMSOL Multiphysics© will be used for calculation of the physical properties of the segment. MELTS software will be used to forward model the geochemical tracing to infer source geometry and composition and melt pathways. Forward modeling of the gravity and magnetic fields of the produced models using MATLAB will allow us to further constrain the density, depth and geometry of the mantle melt regime, leading to a better understanding of the mantle system as a whole. Incorporating the geochemical, and geophysical data to the model represents a fundamental advancement of the ridge modeling process and combining geodynamic models with observational data. This NSF EAPSI award is funded in collaboration with the Japan Society for the Promotion of Science.